RunContext refactor + sync updates

.cursor/plans/script_naming_refactor_424e3277.plan.md

@@ -0,0 +1,272 @@
+---
+name: Script Naming Refactor
+overview: Remove the `emitLegacyScripts` option entirely and implement a new, deterministic script naming convention where each script type has exactly one file extension. Add period encoding to the Windows encoding system and default that setting to true.
+todos:
+  - id: path-encoding
+    content: Add %DOT% to CHAR_ENCODINGS, add %% escape for literal %, default encoding to true
+    status: completed
+  - id: middleware-enum
+    content: Add LocalScript, LegacyScript, LocalScriptDir, LegacyScriptDir middleware variants
+    status: completed
+  - id: script-type
+    content: Simplify ScriptType enum and update snapshot_lua logic
+    status: completed
+  - id: sync-rules
+    content: Add .local.lua/.luau and .legacy.lua/.luau sync rules and init paths
+    status: completed
+  - id: remove-emit-legacy
+    content: Remove emitLegacyScripts from Project, InstanceContext, and all usages
+    status: completed
+  - id: syncback-runcontext
+    content: Update get_best_middleware to check RunContext for Script class
+    status: completed
+  - id: file-extensions
+    content: Update extension_for_middleware with new script types
+    status: completed
+  - id: meta-suffixes
+    content: Add .local and .legacy to meta file suffix stripping
+    status: completed
+  - id: web-api
+    content: Update web/api.rs for new script naming conventions
+    status: completed
+  - id: update-tests
+    content: Update snapshot files and test cases
+    status: completed
+isProject: false
+---
+
+# Script Naming Convention Refactor
+
+## New File Extension Mapping
+
+
+| Script Type                | File Extension |
+| -------------------------- | -------------- |
+| Script (RunContext.Server) | `.server.luau` |
+| Script (RunContext.Client) | `.client.luau` |
+| Script (RunContext.Plugin) | `.plugin.luau` |
+| Script (RunContext.Legacy) | `.legacy.luau` |
+| LocalScript                | `.local.luau`  |
+| ModuleScript               | `.luau`        |
+
+
+## Key Changes
+
+### 1. Add Period Encoding, Percent Escaping, and Default to True
+
+Update `[src/path_encoding.rs](src/path_encoding.rs)`:
+
+1. Add `(".", "%DOT%")` to `CHAR_ENCODINGS`
+2. Add `%%` as escape sequence for literal `%` (encode first, decode last)
+
+```rust
+const CHAR_ENCODINGS: &[(&str, &str)] = &[
+    (".", "%DOT%"),  // NEW
+    ("<", "%LT%"),
+    // ... rest unchanged
+];
+
+pub fn encode_path_name(name: &str) -> String {
+    // ... handle leading/trailing spaces ...
+    
+    // FIRST: Escape existing % as %% (before adding new % signs)
+    let mut encoded_middle = middle.replace("%", "%%");
+    
+    // THEN: Encode special characters (which add new % signs)
+    for (char, encoded) in CHAR_ENCODINGS {
+        encoded_middle = encoded_middle.replace(char, encoded);
+    }
+    // ...
+}
+
+pub fn decode_path_name(name: &str) -> String {
+    // ...
+    // FIRST: Decode %NAME% patterns
+    for (char, encoded) in CHAR_ENCODINGS {
+        result = result.replace(encoded, char);
+    }
+    
+    // LAST: Unescape %% back to %
+    result = result.replace("%%", "%");
+    // ...
+}
+```
+
+This ensures round-tripping works correctly:
+
+- `My%DOT%Thing` encodes to `My%%DOT%%Thing`, decodes back to `My%DOT%Thing`
+- `My.Thing` encodes to `My%DOT%Thing`, decodes back to `My.Thing`
+
+Change the default for `encode_windows_invalid_chars` to `true` in `[src/syncback/mod.rs](src/syncback/mod.rs)` `SyncbackRules::encode_windows_invalid_chars()`:
+
+```rust
+pub fn encode_windows_invalid_chars(&self) -> bool {
+    self.encode_windows_invalid_chars.unwrap_or(true)  // Changed from false to true
+}
+```
+
+Also update the `decode_windows_invalid_chars` logic in `[src/serve_session.rs](src/serve_session.rs)` to default to `true`.
+
+### 2. Add New Middleware Variants
+
+In `[src/snapshot_middleware/mod.rs](src/snapshot_middleware/mod.rs)`, add new variants:
+
+- `LocalScript` - for `.local.lua/.luau` files (LocalScript class)
+- `LegacyScript` - for `.legacy.lua/.luau` files (Script with RunContext.Legacy)
+- `LocalScriptDir` - for `init.local.lua/.luau` directories
+- `LegacyScriptDir` - for `init.legacy.lua/.luau` directories
+
+### 3. Update ScriptType Enum
+
+In `[src/snapshot_middleware/lua.rs](src/snapshot_middleware/lua.rs)`, simplify to:
+
+```rust
+pub enum ScriptType {
+    Server,   // Script + RunContext.Server
+    Client,   // Script + RunContext.Client  
+    Plugin,   // Script + RunContext.Plugin
+    Legacy,   // Script + RunContext.Legacy
+    Local,    // LocalScript
+    Module,   // ModuleScript
+}
+```
+
+Remove `LegacyServer`, `LegacyClient`, `RunContextServer`, `RunContextClient` - these were for the dual-mode system.
+
+### 4. Update Default Sync Rules
+
+In `[src/snapshot_middleware/mod.rs](src/snapshot_middleware/mod.rs)` `default_sync_rules()`:
+
+```rust
+vec![
+    sync_rule!("*.server.lua", ServerScript, ".server.lua"),
+    sync_rule!("*.server.luau", ServerScript, ".server.luau"),
+    sync_rule!("*.client.lua", ClientScript, ".client.lua"),
+    sync_rule!("*.client.luau", ClientScript, ".client.luau"),
+    sync_rule!("*.plugin.lua", PluginScript, ".plugin.lua"),
+    sync_rule!("*.plugin.luau", PluginScript, ".plugin.luau"),
+    sync_rule!("*.legacy.lua", LegacyScript, ".legacy.lua"),     // NEW
+    sync_rule!("*.legacy.luau", LegacyScript, ".legacy.luau"),   // NEW
+    sync_rule!("*.local.lua", LocalScript, ".local.lua"),        // NEW
+    sync_rule!("*.local.luau", LocalScript, ".local.luau"),      // NEW
+    sync_rule!("*.{lua,luau}", ModuleScript),  // Unchanged - catches remaining
+    // ... rest unchanged
+]
+```
+
+### 5. Update Init Path Handling
+
+In `[src/snapshot_middleware/mod.rs](src/snapshot_middleware/mod.rs)` `get_dir_middleware()`:
+
+```rust
+vec![
+    (Middleware::ModuleScriptDir, "init.luau"),
+    (Middleware::ModuleScriptDir, "init.lua"),
+    (Middleware::ServerScriptDir, "init.server.luau"),
+    (Middleware::ServerScriptDir, "init.server.lua"),
+    (Middleware::ClientScriptDir, "init.client.luau"),
+    (Middleware::ClientScriptDir, "init.client.lua"),
+    (Middleware::LocalScriptDir, "init.local.luau"),     // NEW
+    (Middleware::LocalScriptDir, "init.local.lua"),       // NEW
+    (Middleware::LegacyScriptDir, "init.legacy.luau"),   // NEW
+    (Middleware::LegacyScriptDir, "init.legacy.lua"),     // NEW
+    (Middleware::CsvDir, "init.csv"),
+]
+```
+
+### 6. Remove emitLegacyScripts Entirely
+
+Files to modify:
+
+- `[src/project.rs](src/project.rs)` - Remove `emit_legacy_scripts` field from `Project`
+- `[src/snapshot/metadata.rs](src/snapshot/metadata.rs)` - Remove from `InstanceContext`, remove `with_emit_legacy_scripts()`
+- `[src/snapshot_middleware/util.rs](src/snapshot_middleware/util.rs)` - Remove `emit_legacy_scripts_default()`
+- `[src/snapshot_middleware/project.rs](src/snapshot_middleware/project.rs)` - Remove `set_emit_legacy_scripts()` call
+- `[src/serve_session.rs](src/serve_session.rs)` - Remove emit_legacy_scripts usage
+
+### 7. Update Syncback Middleware Selection
+
+In `[src/syncback/mod.rs](src/syncback/mod.rs)` `get_best_middleware()`:
+
+```rust
+middleware = match inst.class.as_str() {
+    "Script" => {
+        // Check RunContext to determine which middleware
+        match inst.properties.get(&ustr("RunContext")) {
+            Some(Variant::Enum(e)) => match e.to_u32() {
+                // Legacy = 0, Server = 1, Client = 2, Plugin = 3
+                0 => Middleware::LegacyScript,
+                1 => Middleware::ServerScript,
+                2 => Middleware::ClientScript,
+                3 => Middleware::PluginScript,
+                _ => Middleware::ServerScript, // fallback
+            },
+            _ => Middleware::LegacyScript, // No RunContext = Legacy behavior
+        }
+    }
+    "LocalScript" => Middleware::LocalScript,
+    "ModuleScript" => Middleware::ModuleScript,
+    // ... rest unchanged
+}
+```
+
+### 8. Update File Name Extensions
+
+In `[src/syncback/file_names.rs](src/syncback/file_names.rs)` `extension_for_middleware()`:
+
+```rust
+Middleware::ServerScript => "server.luau",
+Middleware::ClientScript => "client.luau",
+Middleware::PluginScript => "plugin.luau",
+Middleware::LegacyScript => "legacy.luau",   // NEW
+Middleware::LocalScript => "local.luau",      // NEW
+Middleware::ModuleScript => "luau",
+```
+
+### 9. Update Meta File Suffix Stripping
+
+In `[src/snapshot_middleware/lua.rs](src/snapshot_middleware/lua.rs)` `syncback_lua()` and `[src/snapshot_middleware/meta_file.rs](src/snapshot_middleware/meta_file.rs)`:
+
+Add `.local` and `.legacy` to the suffix stripping logic.
+
+### 10. Update Web API (Two-Way Sync)
+
+In `[src/web/api.rs](src/web/api.rs)`:
+
+- Update script handling to use new naming conventions
+- Remove all `emit_legacy_scripts` references and conditional logic
+
+### 11. Update Test Files
+
+- Delete test projects in `rojo-test/build-tests/nested_runcontext/` that test emitLegacyScripts
+- Update all snapshot files (`.snap`) that contain `emit_legacy_scripts: true/false`
+- Update test cases in `src/snapshot_middleware/lua.rs` to use the new single behavior
+
+### 12. Clean Up Comments
+
+Remove all legacy references and comments about the old dual-mode system throughout the codebase.
+
+## Files to Modify (Summary)
+
+Core changes:
+
+- `src/path_encoding.rs` - Add period encoding (`%DOT%`) and `%%` escape for literal `%`
+- `src/syncback/mod.rs` - Default encode_windows_invalid_chars to true, update middleware selection
+- `src/serve_session.rs` - Default decode_windows_invalid_chars to true
+- `src/snapshot_middleware/mod.rs` - Add middleware variants, update sync rules
+- `src/snapshot_middleware/lua.rs` - Simplify ScriptType, update logic
+- `src/snapshot/metadata.rs` - Remove emit_legacy_scripts
+- `src/project.rs` - Remove emit_legacy_scripts field
+- `src/syncback/mod.rs` - Update middleware selection with RunContext check
+- `src/syncback/file_names.rs` - Add new extensions
+- `src/snapshot_middleware/util.rs` - Remove emit_legacy_scripts_default
+- `src/snapshot_middleware/project.rs` - Remove emit_legacy_scripts propagation
+- `src/serve_session.rs` - Remove emit_legacy_scripts usage
+- `src/web/api.rs` - Update for new conventions
+- `src/snapshot_middleware/meta_file.rs` - Add new suffix handling
+
+Test updates:
+
+- ~40 snapshot files need `emit_legacy_scripts` line removed and `decode_windows_invalid_chars` changed to `true`
+- Test functions need updating to not pass emit_legacy_scripts parameter
+

plugin/src/ChangeBatcher/encodeInstance.lua

@@ -8,6 +8,12 @@
 	- All other instances -> .model.json files or directories
 	
 	Children are recursively encoded and included.
+	
+	DUPLICATE HANDLING:
+	- Instances with duplicate-named siblings at ANY level of the path are skipped
+	- This matches the behavior in ref_properties.rs::is_path_unique
+	- A path is ambiguous if duplicates exist anywhere from the instance to the root
+	- A warning is logged when duplicates are encountered
 ]]
 
 local Packages = script.Parent.Parent.Parent.Packages
@@ -41,9 +47,65 @@ local DIRECTORY_CLASSES = {
 	AdGui = true,
 }
 
+-- Finds duplicate names among a list of instances
+-- Returns a set of names that appear more than once
+local function findDuplicateNames(children: { Instance }): { [string]: boolean }
+	local nameCounts: { [string]: number } = {}
+	local duplicates: { [string]: boolean } = {}
+
+	for _, child in children do
+		local name = child.Name
+		nameCounts[name] = (nameCounts[name] or 0) + 1
+		if nameCounts[name] > 1 then
+			duplicates[name] = true
+		end
+	end
+
+	return duplicates
+end
+
+-- Checks if an instance has duplicate-named siblings
+local function hasDuplicateSiblings(instance: Instance): boolean
+	local parent = instance.Parent
+	if not parent then
+		return false
+	end
+
+	local siblings = parent:GetChildren()
+	local duplicates = findDuplicateNames(siblings)
+	return duplicates[instance.Name] == true
+end
+
+-- Checks if the path to an instance is unique by walking up the tree.
+-- Returns false if ANY ancestor (including the instance itself) has duplicate siblings.
+-- This matches the behavior of is_path_unique in ref_properties.rs
+local function isPathUnique(instance: Instance): boolean
+	local current = instance
+
+	while current do
+		-- Check if current has duplicate-named siblings
+		if hasDuplicateSiblings(current) then
+			return false
+		end
+
+		-- Move up to parent
+		current = current.Parent
+
+		-- Stop at game (DataModel) - we've reached the root
+		if current and current == game then
+			break
+		end
+	end
+
+	return true
+end
+
 -- Forward declaration for recursion
 local encodeInstance
 
+-- Track skipped duplicates for logging
+local skippedDuplicateCount = 0
+
 -- Encode Attributes if present on any instance
 local function encodeAttributes(instance, properties)
 	-- Try to get Attributes - this works for all instance types
@@ -64,7 +126,21 @@ local function encodeAttributes(instance, properties)
 	end
 end
 
-encodeInstance = function(instance, parentId)
+encodeInstance = function(instance, parentId, _skipPathCheck)
+	-- Check if the entire path to this instance is unique (unless we're in a recursive call)
+	-- For top-level instances, we check the entire ancestor chain for duplicates
+	-- For children, the parent already verified the path is unique up to that point,
+	-- so we only need to check siblings at each level (done in the recursion below)
+	if not _skipPathCheck and not isPathUnique(instance) then
+		skippedDuplicateCount += 1
+		Log.warn(
+			"Skipped instance '{}' ({}) - path contains duplicate-named siblings (cannot reliably sync)",
+			instance:GetFullName(),
+			instance.ClassName
+		)
+		return nil
+	end
+
 	local properties = {}
 
 	-- Always try to encode Attributes for any instance type
@@ -111,10 +187,25 @@ encodeInstance = function(instance, parentId)
 	end
 	-- For directory classes (Folder, Configuration, etc.), we only encode Attributes (done above)
 
-	-- Recursively encode children
+	-- Recursively encode children, skipping those with duplicate names
 	local children = {}
-	for _, child in ipairs(instance:GetChildren()) do
+	local childInstances = instance:GetChildren()
-		local encodedChild = encodeInstance(child, nil) -- parentId will be resolved server-side
+	local childDuplicates = findDuplicateNames(childInstances)
+
+	for _, child in ipairs(childInstances) do
+		-- Skip children with duplicate names
+		if childDuplicates[child.Name] then
+			skippedDuplicateCount += 1
+			Log.warn(
+				"Skipped child instance '{}' ({}) - has duplicate-named siblings (cannot reliably sync)",
+				child:GetFullName(),
+				child.ClassName
+			)
+			continue
+		end
+
+		-- Pass true to skip duplicate check since we already checked above
+		local encodedChild = encodeInstance(child, nil, true)
 		if encodedChild then
 			table.insert(children, encodedChild)
 		end
@@ -129,4 +220,20 @@ encodeInstance = function(instance, parentId)
 	}
 end
 
-return encodeInstance
+-- Wrapper function that resets the duplicate count and returns the final count
+local function encodeInstanceWithDuplicateTracking(instance, parentId)
+	skippedDuplicateCount = 0
+	local result = encodeInstance(instance, parentId, false)
+
+	-- Log summary if any duplicates were skipped
+	if skippedDuplicateCount > 0 then
+		Log.warn(
+			"Skipped {} location(s) with duplicate-named siblings during pull (cannot reliably sync)",
+			skippedDuplicateCount
+		)
+	end
+
+	return result, skippedDuplicateCount
+end
+
+return encodeInstanceWithDuplicateTracking

rojo-test/build-test-snapshots/end_to_end__tests__build__client_in_folder.snap

@@ -7,9 +7,10 @@ expression: contents
     <Properties>
       <string name="Name">client_in_folder</string>
     </Properties>
-    <Item class="LocalScript" referent="1">
+    <Item class="Script" referent="1">
       <Properties>
         <string name="Name">localScript</string>
+        <token name="RunContext">2</token>
         <string name="Source">-- This is a Lua client script</string>
       </Properties>
     </Item>

rojo-test/build-test-snapshots/end_to_end__tests__build__client_init.snap

@@ -3,9 +3,10 @@ source: tests/tests/build.rs
 expression: contents
 ---
 <roblox version="4">
-  <Item class="LocalScript" referent="0">
+  <Item class="Script" referent="0">
     <Properties>
       <string name="Name">client_init</string>
+      <token name="RunContext">2</token>
       <string name="Source">return "From folder/init.client.lua"</string>
     </Properties>
   </Item>

rojo-test/build-test-snapshots/end_to_end__tests__build__issue_546.snap

@@ -1,13 +1,13 @@
 ---
 source: tests/tests/build.rs
-assertion_line: 98
 expression: contents
 ---
 <roblox version="4">
-  <Item class="LocalScript" referent="0">
+  <Item class="Script" referent="0">
     <Properties>
       <string name="Name">issue_546</string>
       <bool name="Disabled">true</bool>
+      <token name="RunContext">2</token>
       <string name="Source">print("Hello, world!")</string>
     </Properties>
   </Item>

rojo-test/build-test-snapshots/end_to_end__tests__build__script_meta_disabled.snap

@@ -11,7 +11,7 @@ expression: contents
       <Properties>
         <string name="Name">hello</string>
         <bool name="Disabled">true</bool>
-        <token name="RunContext">0</token>
+        <token name="RunContext">1</token>
         <string name="Source">-- This script should be marked 'Disabled'</string>
       </Properties>
     </Item>

rojo-test/build-test-snapshots/end_to_end__tests__build__server_in_folder.snap

@@ -10,7 +10,7 @@ expression: contents
     <Item class="Script" referent="1">
       <Properties>
         <string name="Name">serverScript</string>
-        <token name="RunContext">0</token>
+        <token name="RunContext">1</token>
         <string name="Source">-- This is a Lua server script</string>
       </Properties>
     </Item>

rojo-test/build-test-snapshots/end_to_end__tests__build__server_init.snap

@@ -6,7 +6,7 @@ expression: contents
   <Item class="Script" referent="0">
     <Properties>
       <string name="Name">server_init</string>
-      <token name="RunContext">0</token>
+      <token name="RunContext">1</token>
       <string name="Source">return "From folder/init.server.luau"</string>
     </Properties>
   </Item>

rojo-test/build-test-snapshots/end_to_end__tests__build__sync_rule_complex.snap

@@ -1,6 +1,5 @@
 ---
 source: tests/tests/build.rs
-assertion_line: 104
 expression: contents
 ---
 <roblox version="4">
@@ -11,13 +10,14 @@ expression: contents
     <Item class="Script" referent="1">
       <Properties>
         <string name="Name">bar</string>
-        <token name="RunContext">0</token>
+        <token name="RunContext">1</token>
         <string name="Source">-- Hello, from bar (a Script)!</string>
       </Properties>
     </Item>
-    <Item class="LocalScript" referent="2">
+    <Item class="Script" referent="2">
       <Properties>
         <string name="Name">baz</string>
+        <token name="RunContext">2</token>
         <string name="Source">-- Hello, from baz (a LocalScript)!</string>
       </Properties>
     </Item>

rojo-test/build-tests/nested_runcontext/default.project.json

@@ -1,13 +0,0 @@
-{
-  "name": "nested_runcontext",
-  "emitLegacyScripts": false,
-  "tree": {
-    "$className": "Folder",
-    "folder1": {
-      "$path": "folder1"
-    },
-    "folder2": {
-      "$path": "folder2"
-    }
-  }
-}

rojo-test/build-tests/nested_runcontext/folder2/default.project.json

@@ -1,7 +0,0 @@
-{
-  "name": "nested_runcontext",
-  "emitLegacyScripts": true,
-  "tree": {
-    "$path": "folder3"
-  }
-}

rojo-test/serve-test-snapshots/end_to_end__tests__serve__scripts_all-2.snap

@@ -1,7 +1,6 @@
 ---
 source: tests/tests/serve.rs
 expression: "read_response.intern_and_redact(&mut redactions, root_id)"
-
 ---
 instances:
   id-2:
@@ -25,7 +24,7 @@ instances:
     Parent: id-2
     Properties:
       RunContext:
-        Enum: 0
+        Enum: 1
       Source:
         String: "-- Hello, from bar!"
   id-4:
@@ -41,4 +40,3 @@ instances:
         String: Updated foo!
 messageCursor: 1
 sessionId: id-1
-

rojo-test/serve-test-snapshots/end_to_end__tests__serve__scripts_all.snap

@@ -1,7 +1,6 @@
 ---
 source: tests/tests/serve.rs
 expression: "read_response.intern_and_redact(&mut redactions, root_id)"
-
 ---
 instances:
   id-2:
@@ -25,7 +24,7 @@ instances:
     Parent: id-2
     Properties:
       RunContext:
-        Enum: 0
+        Enum: 1
       Source:
         String: "-- Hello, from bar!"
   id-4:
@@ -41,4 +40,3 @@ instances:
         String: "-- Hello, from foo!"
 messageCursor: 0
 sessionId: id-1
-

rojo-test/serve-test-snapshots/end_to_end__tests__serve__sync_rule_complex_all.snap

@@ -1,6 +1,5 @@
 ---
 source: tests/tests/serve.rs
-assertion_line: 284
 expression: "read_response.intern_and_redact(&mut redactions, root_id)"
 ---
 instances:
@@ -28,18 +27,20 @@ instances:
     Parent: id-2
     Properties:
       RunContext:
-        Enum: 0
+        Enum: 1
       Source:
         String: "-- Hello, from bar (a Script)!"
   id-4:
     Children: []
-    ClassName: LocalScript
+    ClassName: Script
     Id: id-4
     Metadata:
       ignoreUnknownInstances: false
     Name: baz
     Parent: id-2
     Properties:
+      RunContext:
+        Enum: 2
       Source:
         String: "-- Hello, from baz (a LocalScript)!"
   id-5:
@@ -77,4 +78,3 @@ instances:
         String: "Hello, from qux (a .rojo file that's turned into a StringValue)!"
 messageCursor: 0
 sessionId: id-1
-

src/path_encoding.rs

@@ -1,15 +1,20 @@
-//! Encoding and decoding utilities for Windows-invalid filename characters.
+//! Encoding and decoding utilities for special filename characters.
 //!
-//! Windows does not allow the following characters in file names:
+//! This module encodes characters that are problematic in file names:
-//! < > : " / \ | ? *
+//! - Windows-invalid characters: < > : " / \ | ? *
+//! - Periods (.) to prevent conflicts with file extension parsing
+//! - Leading/trailing spaces
+//! - Literal percent signs (%) to allow round-tripping
 //!
-//! Windows also does not allow leading/trailing spaces in file names.
+//! Characters are encoded using a %NAME% format (e.g., `<` becomes `%LT%`,
-//!
+//! `.` becomes `%DOT%`). Literal `%` is escaped as `%%` (like printf).
-//! This module provides functions to encode these characters using a %NAME%
-//! format (e.g., `<` becomes `%LT%`) and decode them back.
 
-/// Mapping of Windows-invalid characters to their encoded representations.
+use std::collections::HashMap;
+use std::sync::OnceLock;
+
+/// Mapping of special characters to their encoded representations.
 const CHAR_ENCODINGS: &[(&str, &str)] = &[
+    (".", "%DOT%"),
     ("<", "%LT%"),
     (">", "%GT%"),
     (":", "%COLON%"),
@@ -21,13 +26,27 @@ const CHAR_ENCODINGS: &[(&str, &str)] = &[
     ("*", "%STAR%"),
 ];
 
+/// Returns a map from encoded pattern (e.g., "DOT") to decoded char (e.g., ".").
+fn get_decode_map() -> &'static HashMap<&'static str, &'static str> {
+    static DECODE_MAP: OnceLock<HashMap<&'static str, &'static str>> = OnceLock::new();
+    DECODE_MAP.get_or_init(|| {
+        let mut map = HashMap::new();
+        for (char, encoded) in CHAR_ENCODINGS {
+            // Strip the leading and trailing % from the pattern
+            let pattern = &encoded[1..encoded.len() - 1];
+            map.insert(pattern, *char);
+        }
+        map
+    })
+}
+
 const SPACE_ENCODING: &str = "%SPACE%";
 
-/// Encodes Windows-invalid characters in a file name.
+/// Encodes special characters in a file name.
 ///
-/// This replaces characters like `<`, `>`, `:`, `"`, `/`, `\`, `|`, `?`, `*`
+/// This replaces characters like `.`, `<`, `>`, `:`, `"`, `/`, `\`, `|`, `?`, `*`
-/// with their encoded representations like `%LT%`, `%GT%`, etc.
+/// with their encoded representations like `%DOT%`, `%LT%`, `%GT%`, etc.
-/// Leading and trailing spaces are encoded as `%SPACE%`.
+/// Literal `%` is escaped as `%%`. Leading and trailing spaces are encoded as `%SPACE%`.
 pub fn encode_path_name(name: &str) -> String {
     // Count leading and trailing spaces first (before any modifications)
     let leading_spaces = name.len() - name.trim_start_matches(' ').len();
@@ -36,8 +55,10 @@ pub fn encode_path_name(name: &str) -> String {
     // Get the middle part (without leading/trailing spaces)
     let middle = &name[leading_spaces..name.len() - trailing_spaces];
 
-    // Encode invalid characters in the middle part
+    // First: escape % as %% (before adding new % signs from encodings)
-    let mut encoded_middle = middle.to_string();
+    let mut encoded_middle = middle.replace('%', "%%");
+
+    // Then: encode special characters
     for (char, encoded) in CHAR_ENCODINGS {
         encoded_middle = encoded_middle.replace(char, encoded);
     }
@@ -49,11 +70,13 @@ pub fn encode_path_name(name: &str) -> String {
     format!("{}{}{}", encoded_prefix, encoded_middle, encoded_suffix)
 }
 
-/// Decodes encoded Windows-invalid characters back to their original form.
+/// Decodes encoded special characters back to their original form.
 ///
-/// This replaces encoded representations like `%LT%`, `%GT%`, etc. back
+/// This replaces encoded representations like `%DOT%`, `%LT%`, `%GT%`, etc.
-/// to their original characters `<`, `>`, etc.
+/// back to their original characters `.`, `<`, `>`, etc.
-/// `%SPACE%` at the start/end is decoded back to spaces.
+/// `%%` is decoded to literal `%`. `%SPACE%` at the start/end is decoded back to spaces.
+///
+/// Uses a proper left-to-right parser to correctly handle `%%` escaping.
 pub fn decode_path_name(name: &str) -> String {
     let mut result = name.to_string();
 
@@ -71,15 +94,83 @@ pub fn decode_path_name(name: &str) -> String {
         result = result[..result.len() - SPACE_ENCODING.len()].to_string();
     }
 
-    // Decode invalid characters in the middle
+    // Parse and decode the middle part
-    for (char, encoded) in CHAR_ENCODINGS {
+    let decoded_middle = decode_patterns(&result);
-        result = result.replace(encoded, char);
-    }
 
     // Rebuild with actual spaces
     let prefix = " ".repeat(leading_spaces);
     let suffix = " ".repeat(trailing_spaces);
-    format!("{}{}{}", prefix, result, suffix)
+    format!("{}{}{}", prefix, decoded_middle, suffix)
+}
+
+/// Parses an encoded string left-to-right, properly handling `%%` escapes and `%NAME%` patterns.
+fn decode_patterns(input: &str) -> String {
+    let decode_map = get_decode_map();
+    let chars: Vec<char> = input.chars().collect();
+    let mut output = String::with_capacity(input.len());
+    let mut i = 0;
+
+    while i < chars.len() {
+        if chars[i] == '%' {
+            // Check for %% (escaped percent)
+            if i + 1 < chars.len() && chars[i + 1] == '%' {
+                output.push('%');
+                i += 2;
+                continue;
+            }
+
+            // Try to match a %NAME% pattern
+            if let Some((decoded, consumed)) = try_decode_pattern(&chars, i, decode_map) {
+                output.push_str(&decoded);
+                i += consumed;
+                continue;
+            }
+        }
+
+        // Regular character, just copy it
+        output.push(chars[i]);
+        i += 1;
+    }
+
+    output
+}
+
+/// Tries to decode a %NAME% pattern starting at position `start`.
+/// Returns Some((decoded_string, chars_consumed)) if successful, None otherwise.
+fn try_decode_pattern(
+    chars: &[char],
+    start: usize,
+    decode_map: &HashMap<&str, &str>,
+) -> Option<(String, usize)> {
+    // Must start with %
+    if chars.get(start) != Some(&'%') {
+        return None;
+    }
+
+    // Find the closing %
+    let mut end = start + 1;
+    while end < chars.len() && chars[end] != '%' {
+        // Pattern names are uppercase letters only
+        if !chars[end].is_ascii_uppercase() {
+            return None;
+        }
+        end += 1;
+    }
+
+    // Must have found a closing %
+    if end >= chars.len() || chars[end] != '%' {
+        return None;
+    }
+
+    // Extract the pattern name (without the % delimiters)
+    let pattern_name: String = chars[start + 1..end].iter().collect();
+
+    // Look up the pattern
+    if let Some(&decoded) = decode_map.get(pattern_name.as_str()) {
+        Some((decoded.to_string(), end - start + 1))
+    } else {
+        None
+    }
 }
 
 #[cfg(test)]
@@ -88,15 +179,15 @@ mod tests {
 
     #[test]
     fn test_encode_all_chars() {
-        let input = r#"<>:"/\|?*"#;
+        let input = r#".<>:"/\|?*"#;
-        let expected = "%LT%%GT%%COLON%%QUOTE%%SLASH%%BACKSLASH%%PIPE%%QUESTION%%STAR%";
+        let expected = "%DOT%%LT%%GT%%COLON%%QUOTE%%SLASH%%BACKSLASH%%PIPE%%QUESTION%%STAR%";
         assert_eq!(encode_path_name(input), expected);
     }
 
     #[test]
     fn test_decode_all_chars() {
-        let input = "%LT%%GT%%COLON%%QUOTE%%SLASH%%BACKSLASH%%PIPE%%QUESTION%%STAR%";
+        let input = "%DOT%%LT%%GT%%COLON%%QUOTE%%SLASH%%BACKSLASH%%PIPE%%QUESTION%%STAR%";
-        let expected = r#"<>:"/\|?*"#;
+        let expected = r#".<>:"/\|?*"#;
         assert_eq!(decode_path_name(input), expected);
     }
 
@@ -154,4 +245,67 @@ mod tests {
         let decoded = decode_path_name(&encoded);
         assert_eq!(decoded, original);
     }
+
+    #[test]
+    fn test_encode_period() {
+        let input = "My.Script";
+        let expected = "My%DOT%Script";
+        assert_eq!(encode_path_name(input), expected);
+    }
+
+    #[test]
+    fn test_decode_period() {
+        let input = "My%DOT%Script";
+        let expected = "My.Script";
+        assert_eq!(decode_path_name(input), expected);
+    }
+
+    #[test]
+    fn test_roundtrip_with_period() {
+        let original = "My.Module.Name";
+        let encoded = encode_path_name(original);
+        let decoded = decode_path_name(&encoded);
+        assert_eq!(decoded, original);
+    }
+
+    #[test]
+    fn test_encode_percent() {
+        let input = "My%Thing";
+        let expected = "My%%Thing";
+        assert_eq!(encode_path_name(input), expected);
+    }
+
+    #[test]
+    fn test_decode_percent() {
+        let input = "My%%Thing";
+        let expected = "My%Thing";
+        assert_eq!(decode_path_name(input), expected);
+    }
+
+    #[test]
+    fn test_roundtrip_with_percent() {
+        let original = "My%Thing";
+        let encoded = encode_path_name(original);
+        let decoded = decode_path_name(&encoded);
+        assert_eq!(decoded, original);
+    }
+
+    #[test]
+    fn test_percent_encoding_pattern_roundtrip() {
+        // This tests that a name containing what looks like an encoding pattern
+        // round-trips correctly and doesn't get incorrectly decoded
+        let original = "My%DOT%Thing";
+        let encoded = encode_path_name(original);
+        assert_eq!(encoded, "My%%DOT%%Thing");
+        let decoded = decode_path_name(&encoded);
+        assert_eq!(decoded, original);
+    }
+
+    #[test]
+    fn test_combined_period_and_percent() {
+        let original = "My.%Thing.Other";
+        let encoded = encode_path_name(original);
+        let decoded = decode_path_name(&encoded);
+        assert_eq!(decoded, original);
+    }
 }

src/project.rs

@@ -110,12 +110,6 @@ pub struct Project {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub serve_address: Option<IpAddr>,
 
-    /// Determines if Rojo should emit scripts with the appropriate `RunContext`
-    /// for `*.client.lua` and `*.server.lua` files in the project instead of
-    /// using `Script` and `LocalScript` Instances.
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub emit_legacy_scripts: Option<bool>,
-
     /// A list of globs, relative to the folder the project file is in, that
     /// match files that should be excluded if Rojo encounters them.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
@@ -573,7 +567,6 @@ mod test {
                 "$path": "src", // Comment after value
             },
             "servePort": 34567,
-            "emitLegacyScripts": false,
             // Test glob parsing with comments
             "globIgnorePaths": [
                 "**/*.spec.lua", // Ignore test files
@@ -601,7 +594,6 @@ mod test {
         // Verify the parsed values
         assert_eq!(project.name, Some("TestProject".to_string()));
         assert_eq!(project.serve_port, Some(34567));
-        assert_eq!(project.emit_legacy_scripts, Some(false));
 
         // Verify glob_ignore_paths were parsed correctly
         assert_eq!(project.glob_ignore_paths.len(), 2);

src/serve_session.rs

@@ -110,10 +110,9 @@ impl ServeSession {
             .syncback_rules
             .as_ref()
             .map(|rules| rules.encode_windows_invalid_chars())
-            .unwrap_or(false);
+            .unwrap_or(true);
 
-        let mut instance_context =
+        let mut instance_context = InstanceContext::new();
-            InstanceContext::with_emit_legacy_scripts(root_project.emit_legacy_scripts);
         instance_context.set_decode_windows_invalid_chars(decode_windows_invalid_chars);
 
         log::trace!("Generating snapshot of instances from VFS");

src/snapshot/metadata.rs

@@ -8,11 +8,7 @@ use anyhow::Context;
 use serde::{Deserialize, Serialize};
 
 use crate::{
-    glob::Glob,
+    glob::Glob, path_serializer, project::ProjectNode, snapshot_middleware::Middleware, RojoRef,
-    path_serializer,
-    project::ProjectNode,
-    snapshot_middleware::{emit_legacy_scripts_default, Middleware},
-    RojoRef,
 };
 
 /// Rojo-specific metadata that can be associated with an instance or a snapshot
@@ -142,32 +138,26 @@ impl Default for InstanceMetadata {
 pub struct InstanceContext {
     #[serde(skip_serializing_if = "Vec::is_empty")]
     pub path_ignore_rules: Arc<Vec<PathIgnoreRule>>,
-    pub emit_legacy_scripts: bool,
     #[serde(skip_serializing_if = "Vec::is_empty")]
     pub sync_rules: Vec<SyncRule>,
-    /// Whether to decode Windows-invalid characters in file names.
+    /// Whether to decode special characters in file names.
-    /// Characters like `%LT%`, `%GT%`, `%COLON%`, etc. will be decoded
+    /// Characters like `%DOT%`, `%LT%`, `%GT%`, `%COLON%`, etc. will be decoded
-    /// back to `<`, `>`, `:`, etc. in instance names sent to the plugin.
+    /// back to `.`, `<`, `>`, `:`, etc. in instance names sent to the plugin.
-    #[serde(default)]
+    /// Defaults to true.
+    #[serde(default = "decode_windows_invalid_chars_default")]
     pub decode_windows_invalid_chars: bool,
 }
 
+fn decode_windows_invalid_chars_default() -> bool {
+    true
+}
+
 impl InstanceContext {
     pub fn new() -> Self {
         Self {
             path_ignore_rules: Arc::new(Vec::new()),
-            emit_legacy_scripts: emit_legacy_scripts_default().unwrap(),
             sync_rules: Vec::new(),
-            decode_windows_invalid_chars: false,
+            decode_windows_invalid_chars: true,
-        }
-    }
-
-    pub fn with_emit_legacy_scripts(emit_legacy_scripts: Option<bool>) -> Self {
-        Self {
-            emit_legacy_scripts: emit_legacy_scripts
-                .or_else(emit_legacy_scripts_default)
-                .unwrap(),
-            ..Self::new()
         }
     }
 
@@ -206,10 +196,6 @@ impl InstanceContext {
         self.sync_rules.clear();
     }
 
-    pub fn set_emit_legacy_scripts(&mut self, emit_legacy_scripts: bool) {
-        self.emit_legacy_scripts = emit_legacy_scripts;
-    }
-
     /// Returns the middleware specified by the first sync rule that
     /// matches the provided path. This does not handle default syncing rules.
     pub fn get_user_sync_rule(&self, path: &Path) -> Option<&SyncRule> {

src/snapshot/tests/snapshots/librojo__snapshot__tests__apply__add_property.snap

@@ -12,8 +12,7 @@ metadata:
   ignore_unknown_instances: false
   relevant_paths: []
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot/tests/snapshots/librojo__snapshot__tests__apply__remove_property_after_patch.snap

@@ -10,8 +10,7 @@ metadata:
   ignore_unknown_instances: false
   relevant_paths: []
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot/tests/snapshots/librojo__snapshot__tests__apply__remove_property_initial.snap

@@ -12,8 +12,7 @@ metadata:
   ignore_unknown_instances: false
   relevant_paths: []
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot/tests/snapshots/librojo__snapshot__tests__apply__set_name_and_class_name.snap

@@ -10,8 +10,7 @@ metadata:
   ignore_unknown_instances: false
   relevant_paths: []
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot/tests/snapshots/librojo__snapshot__tests__compute__add_child.snap

@@ -11,8 +11,7 @@ added_instances:
         ignore_unknown_instances: false
         relevant_paths: []
         context:
-          emit_legacy_scripts: true
+          decode_windows_invalid_chars: true
-          decode_windows_invalid_chars: false
         specified_id: ~
         middleware: ~
         schema: ~

src/snapshot_middleware/csv.rs

@@ -383,7 +383,7 @@ Ack,Ack!,,An exclamation of despair,¡Ay!"#,
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_csv_init(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/root/init.csv"),
             "root",
@@ -421,7 +421,7 @@ Ack,Ack!,,An exclamation of despair,¡Ay!"#,
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_csv_init(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/root/init.csv"),
             "root",

src/snapshot_middleware/lua.rs

@@ -21,14 +21,12 @@ use super::{
 
 #[derive(Debug)]
 pub enum ScriptType {
-    Server,
+    Server, // Script + RunContext.Server
-    Client,
+    Client, // Script + RunContext.Client
-    Module,
+    Module, // ModuleScript
-    Plugin,
+    Plugin, // Script + RunContext.Plugin
-    LegacyServer,
+    Legacy, // Script + RunContext.Legacy
-    LegacyClient,
+    Local,  // LocalScript
-    RunContextServer,
-    RunContextClient,
 }
 
 /// Core routine for turning Lua files into snapshots.
@@ -47,26 +45,12 @@ pub fn snapshot_lua(
         .items;
 
     let (class_name, run_context) = match script_type {
-        ScriptType::Server => {
+        ScriptType::Server => ("Script", run_context_enums.get("Server")),
-            if context.emit_legacy_scripts {
+        ScriptType::Client => ("Script", run_context_enums.get("Client")),
-                ("Script", run_context_enums.get("Legacy"))
-            } else {
-                ("Script", run_context_enums.get("Server"))
-            }
-        }
-        ScriptType::Client => {
-            if context.emit_legacy_scripts {
-                ("LocalScript", None)
-            } else {
-                ("Script", run_context_enums.get("Client"))
-            }
-        }
         ScriptType::Module => ("ModuleScript", None),
         ScriptType::Plugin => ("Script", run_context_enums.get("Plugin")),
-        ScriptType::LegacyServer => ("Script", run_context_enums.get("Legacy")),
+        ScriptType::Legacy => ("Script", run_context_enums.get("Legacy")),
-        ScriptType::LegacyClient => ("LocalScript", None),
+        ScriptType::Local => ("LocalScript", None),
-        ScriptType::RunContextServer => ("Script", run_context_enums.get("Server")),
-        ScriptType::RunContextClient => ("Script", run_context_enums.get("Client")),
     };
 
     let contents = vfs.read_to_string_lf_normalized(path)?;
@@ -101,8 +85,9 @@ pub fn snapshot_lua(
 /// Attempts to snapshot an 'init' Lua script contained inside of a folder with
 /// the given name.
 ///
-/// Scripts named `init.lua`, `init.server.lua`, or `init.client.lua` usurp
+/// Scripts named `init.lua`, `init.server.lua`, `init.client.lua`, `init.local.lua`,
-/// their parents, which acts similarly to `__init__.py` from the Python world.
+/// `init.legacy.lua`, or `init.plugin.lua` usurp their parents, which acts similarly
+/// to `__init__.py` from the Python world.
 pub fn snapshot_lua_init(
     context: &InstanceContext,
     vfs: &Vfs,
@@ -115,9 +100,8 @@ pub fn snapshot_lua_init(
 
     if dir_snapshot.class_name != "Folder" {
         anyhow::bail!(
-            "init.lua, init.server.lua, and init.client.lua can \
+            "init scripts can only be used if the instance produced by the \
-             only be used if the instance produced by the containing \
+             containing directory would be a Folder.\n\
-             directory would be a Folder.\n\
              \n\
              The directory {} turned into an instance of class {}.",
             folder_path.display(),
@@ -177,6 +161,8 @@ pub fn syncback_lua<'sync>(
                 .strip_suffix(".server")
                 .or_else(|| file_stem.strip_suffix(".client"))
                 .or_else(|| file_stem.strip_suffix(".plugin"))
+                .or_else(|| file_stem.strip_suffix(".local"))
+                .or_else(|| file_stem.strip_suffix(".legacy"))
                 .unwrap_or(file_stem);
             let meta_name = if meta_name.is_empty() {
                 if snapshot.encode_windows_invalid_chars() {
@@ -211,7 +197,9 @@ pub fn syncback_lua_init<'sync>(
         ScriptType::Server => "init.server.luau",
         ScriptType::Client => "init.client.luau",
         ScriptType::Module => "init.luau",
-        _ => anyhow::bail!("syncback is not yet implemented for {script_type:?}"),
+        ScriptType::Plugin => "init.plugin.luau",
+        ScriptType::Legacy => "init.legacy.luau",
+        ScriptType::Local => "init.local.luau",
     });
 
     let contents = if let Some(Variant::String(source)) = new_inst.properties.get(&ustr("Source")) {
@@ -248,7 +236,7 @@ mod test {
     use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
-    fn class_module_from_vfs() {
+    fn module_from_vfs() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/foo.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -256,7 +244,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/foo.lua"),
             "foo",
@@ -271,30 +259,7 @@ mod test {
     }
 
     #[test]
-    fn runcontext_module_from_vfs() {
+    fn plugin_from_vfs() {
-        let mut imfs = InMemoryFs::new();
-        imfs.load_snapshot("/foo.lua", VfsSnapshot::file("Hello there!"))
-            .unwrap();
-
-        let vfs = Vfs::new(imfs);
-
-        let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
-            &vfs,
-            Path::new("/foo.lua"),
-            "foo",
-            ScriptType::Module,
-        )
-        .unwrap()
-        .unwrap();
-
-        insta::with_settings!({ sort_maps => true }, {
-            insta::assert_yaml_snapshot!(instance_snapshot);
-        });
-    }
-
-    #[test]
-    fn plugin_module_from_vfs() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/foo.plugin.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -302,7 +267,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/foo.plugin.lua"),
             "foo",
@@ -317,7 +282,7 @@ mod test {
     }
 
     #[test]
-    fn class_server_from_vfs() {
+    fn server_from_vfs() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/foo.server.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -325,7 +290,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/foo.server.lua"),
             "foo",
@@ -340,30 +305,7 @@ mod test {
     }
 
     #[test]
-    fn runcontext_server_from_vfs() {
+    fn client_from_vfs() {
-        let mut imfs = InMemoryFs::new();
-        imfs.load_snapshot("/foo.server.lua", VfsSnapshot::file("Hello there!"))
-            .unwrap();
-
-        let vfs = Vfs::new(imfs);
-
-        let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
-            &vfs,
-            Path::new("/foo.server.lua"),
-            "foo",
-            ScriptType::Server,
-        )
-        .unwrap()
-        .unwrap();
-
-        insta::with_settings!({ sort_maps => true }, {
-            insta::assert_yaml_snapshot!(instance_snapshot);
-        });
-    }
-
-    #[test]
-    fn class_client_from_vfs() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/foo.client.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -371,7 +313,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/foo.client.lua"),
             "foo",
@@ -386,19 +328,42 @@ mod test {
     }
 
     #[test]
-    fn runcontext_client_from_vfs() {
+    fn local_from_vfs() {
         let mut imfs = InMemoryFs::new();
-        imfs.load_snapshot("/foo.client.lua", VfsSnapshot::file("Hello there!"))
+        imfs.load_snapshot("/foo.local.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
 
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
+            &InstanceContext::new(),
             &vfs,
-            Path::new("/foo.client.lua"),
+            Path::new("/foo.local.lua"),
             "foo",
-            ScriptType::Client,
+            ScriptType::Local,
+        )
+        .unwrap()
+        .unwrap();
+
+        insta::with_settings!({ sort_maps => true }, {
+            insta::assert_yaml_snapshot!(instance_snapshot);
+        });
+    }
+
+    #[test]
+    fn legacy_from_vfs() {
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.legacy.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
+
+        let vfs = Vfs::new(imfs);
+
+        let instance_snapshot = snapshot_lua(
+            &InstanceContext::new(),
+            &vfs,
+            Path::new("/foo.legacy.lua"),
+            "foo",
+            ScriptType::Legacy,
         )
         .unwrap()
         .unwrap();
@@ -420,7 +385,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua_init(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/root/init.lua"),
             "root",
@@ -452,7 +417,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua_init(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/root/init.lua"),
             "root",
@@ -467,7 +432,7 @@ mod test {
     }
 
     #[test]
-    fn class_module_with_meta() {
+    fn module_with_meta() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/foo.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -486,7 +451,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/foo.lua"),
             "foo",
@@ -501,41 +466,7 @@ mod test {
     }
 
     #[test]
-    fn runcontext_module_with_meta() {
+    fn server_with_meta() {
-        let mut imfs = InMemoryFs::new();
-        imfs.load_snapshot("/foo.lua", VfsSnapshot::file("Hello there!"))
-            .unwrap();
-        imfs.load_snapshot(
-            "/foo.meta.json",
-            VfsSnapshot::file(
-                r#"
-                    {
-                        "ignoreUnknownInstances": true
-                    }
-                "#,
-            ),
-        )
-        .unwrap();
-
-        let vfs = Vfs::new(imfs);
-
-        let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
-            &vfs,
-            Path::new("/foo.lua"),
-            "foo",
-            ScriptType::Module,
-        )
-        .unwrap()
-        .unwrap();
-
-        insta::with_settings!({ sort_maps => true }, {
-            insta::assert_yaml_snapshot!(instance_snapshot);
-        });
-    }
-
-    #[test]
-    fn class_script_with_meta() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/foo.server.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -554,7 +485,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
             &vfs,
             Path::new("/foo.server.lua"),
             "foo",
@@ -569,41 +500,7 @@ mod test {
     }
 
     #[test]
-    fn runcontext_script_with_meta() {
+    fn server_disabled() {
-        let mut imfs = InMemoryFs::new();
-        imfs.load_snapshot("/foo.server.lua", VfsSnapshot::file("Hello there!"))
-            .unwrap();
-        imfs.load_snapshot(
-            "/foo.meta.json",
-            VfsSnapshot::file(
-                r#"
-                    {
-                        "ignoreUnknownInstances": true
-                    }
-                "#,
-            ),
-        )
-        .unwrap();
-
-        let vfs = Vfs::new(imfs);
-
-        let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
-            &vfs,
-            Path::new("/foo.server.lua"),
-            "foo",
-            ScriptType::Server,
-        )
-        .unwrap()
-        .unwrap();
-
-        insta::with_settings!({ sort_maps => true }, {
-            insta::assert_yaml_snapshot!(instance_snapshot);
-        });
-    }
-
-    #[test]
-    fn class_script_disabled() {
         let mut imfs = InMemoryFs::new();
         imfs.load_snapshot("/bar.server.lua", VfsSnapshot::file("Hello there!"))
             .unwrap();
@@ -624,43 +521,7 @@ mod test {
         let vfs = Vfs::new(imfs);
 
         let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(true)),
+            &InstanceContext::new(),
-            &vfs,
-            Path::new("/bar.server.lua"),
-            "bar",
-            ScriptType::Server,
-        )
-        .unwrap()
-        .unwrap();
-
-        insta::with_settings!({ sort_maps => true }, {
-            insta::assert_yaml_snapshot!(instance_snapshot);
-        });
-    }
-
-    #[test]
-    fn runcontext_script_disabled() {
-        let mut imfs = InMemoryFs::new();
-        imfs.load_snapshot("/bar.server.lua", VfsSnapshot::file("Hello there!"))
-            .unwrap();
-        imfs.load_snapshot(
-            "/bar.meta.json",
-            VfsSnapshot::file(
-                r#"
-                    {
-                        "properties": {
-                            "Disabled": true
-                        }
-                    }
-                "#,
-            ),
-        )
-        .unwrap();
-
-        let vfs = Vfs::new(imfs);
-
-        let instance_snapshot = snapshot_lua(
-            &InstanceContext::with_emit_legacy_scripts(Some(false)),
             &vfs,
             Path::new("/bar.server.lua"),
             "bar",

src/snapshot_middleware/meta_file.rs

@@ -55,13 +55,14 @@ impl AdjacentMetadata {
         // Use the file stem from the actual path (which has encoded chars)
         // rather than the decoded name, so meta files are found correctly
         // when encodeWindowsInvalidChars is enabled.
-        // Strip known script type suffixes (.server, .client, .plugin) to get
+        // Strip known script type suffixes to get the base name for the meta file.
-        // the base name for the meta file.
         let file_stem = path.file_stem().and_then(|s| s.to_str()).unwrap_or("");
         let base_name = file_stem
             .strip_suffix(".server")
             .or_else(|| file_stem.strip_suffix(".client"))
             .or_else(|| file_stem.strip_suffix(".plugin"))
+            .or_else(|| file_stem.strip_suffix(".local"))
+            .or_else(|| file_stem.strip_suffix(".legacy"))
             .unwrap_or(file_stem);
         let meta_path_json = path.with_file_name(format!("{base_name}.meta.json"));
         let meta_path_jsonc = path.with_file_name(format!("{base_name}.meta.jsonc"));

src/snapshot_middleware/mod.rs

@@ -53,10 +53,7 @@ use self::{
     yaml::snapshot_yaml,
 };
 
-pub use self::{
+pub use self::{lua::ScriptType, project::snapshot_project_node, util::PathExt};
-    lua::ScriptType, project::snapshot_project_node, util::emit_legacy_scripts_default,
-    util::PathExt,
-};
 
 /// Returns an `InstanceSnapshot` for the provided path.
 /// This will inspect the path and find the appropriate middleware for it,
@@ -98,6 +95,7 @@ pub fn snapshot_from_vfs(
         // TODO: Is this even necessary anymore?
         match file_name {
             "init.server.luau" | "init.server.lua" | "init.client.luau" | "init.client.lua"
+            | "init.local.luau" | "init.local.lua" | "init.legacy.luau" | "init.legacy.lua"
             | "init.luau" | "init.lua" | "init.csv" => return Ok(None),
             _ => {}
         }
@@ -131,6 +129,10 @@ fn get_dir_middleware<'path>(
             (Middleware::ServerScriptDir, "init.server.lua"),
             (Middleware::ClientScriptDir, "init.client.luau"),
             (Middleware::ClientScriptDir, "init.client.lua"),
+            (Middleware::LocalScriptDir, "init.local.luau"),
+            (Middleware::LocalScriptDir, "init.local.lua"),
+            (Middleware::LegacyScriptDir, "init.legacy.luau"),
+            (Middleware::LegacyScriptDir, "init.legacy.lua"),
             (Middleware::CsvDir, "init.csv"),
         ]
     });
@@ -197,10 +199,8 @@ pub enum Middleware {
     ClientScript,
     ModuleScript,
     PluginScript,
-    LegacyClientScript,
+    LocalScript,
-    LegacyServerScript,
+    LegacyScript,
-    RunContextServerScript,
-    RunContextClientScript,
     Project,
     Rbxm,
     Rbxmx,
@@ -218,6 +218,10 @@ pub enum Middleware {
     #[serde(skip_deserializing)]
     ModuleScriptDir,
     #[serde(skip_deserializing)]
+    LocalScriptDir,
+    #[serde(skip_deserializing)]
+    LegacyScriptDir,
+    #[serde(skip_deserializing)]
     CsvDir,
 }
 
@@ -239,18 +243,8 @@ impl Middleware {
             Self::ClientScript => snapshot_lua(context, vfs, path, name, ScriptType::Client),
             Self::ModuleScript => snapshot_lua(context, vfs, path, name, ScriptType::Module),
             Self::PluginScript => snapshot_lua(context, vfs, path, name, ScriptType::Plugin),
-            Self::LegacyClientScript => {
+            Self::LocalScript => snapshot_lua(context, vfs, path, name, ScriptType::Local),
-                snapshot_lua(context, vfs, path, name, ScriptType::LegacyClient)
+            Self::LegacyScript => snapshot_lua(context, vfs, path, name, ScriptType::Legacy),
-            }
-            Self::LegacyServerScript => {
-                snapshot_lua(context, vfs, path, name, ScriptType::LegacyServer)
-            }
-            Self::RunContextClientScript => {
-                snapshot_lua(context, vfs, path, name, ScriptType::RunContextClient)
-            }
-            Self::RunContextServerScript => {
-                snapshot_lua(context, vfs, path, name, ScriptType::RunContextServer)
-            }
             Self::Project => snapshot_project(context, vfs, path, name),
             Self::Rbxm => snapshot_rbxm(context, vfs, path, name),
             Self::Rbxmx => snapshot_rbxmx(context, vfs, path, name),
@@ -269,6 +263,10 @@ impl Middleware {
             Self::ModuleScriptDir => {
                 snapshot_lua_init(context, vfs, path, name, ScriptType::Module)
             }
+            Self::LocalScriptDir => snapshot_lua_init(context, vfs, path, name, ScriptType::Local),
+            Self::LegacyScriptDir => {
+                snapshot_lua_init(context, vfs, path, name, ScriptType::Legacy)
+            }
             Self::CsvDir => snapshot_csv_init(context, vfs, path, name),
         };
         if let Ok(Some(ref mut snapshot)) = output {
@@ -299,6 +297,9 @@ impl Middleware {
             Middleware::ServerScript => syncback_lua(snapshot),
             Middleware::ClientScript => syncback_lua(snapshot),
             Middleware::ModuleScript => syncback_lua(snapshot),
+            Middleware::PluginScript => syncback_lua(snapshot),
+            Middleware::LocalScript => syncback_lua(snapshot),
+            Middleware::LegacyScript => syncback_lua(snapshot),
             Middleware::Rbxm => syncback_rbxm(snapshot),
             Middleware::Rbxmx => syncback_rbxmx(snapshot),
             Middleware::Toml => anyhow::bail!("cannot syncback Toml middleware"),
@@ -309,15 +310,9 @@ impl Middleware {
             Middleware::ServerScriptDir => syncback_lua_init(ScriptType::Server, snapshot),
             Middleware::ClientScriptDir => syncback_lua_init(ScriptType::Client, snapshot),
             Middleware::ModuleScriptDir => syncback_lua_init(ScriptType::Module, snapshot),
+            Middleware::LocalScriptDir => syncback_lua_init(ScriptType::Local, snapshot),
+            Middleware::LegacyScriptDir => syncback_lua_init(ScriptType::Legacy, snapshot),
             Middleware::CsvDir => syncback_csv_init(snapshot),
-
-            Middleware::PluginScript
-            | Middleware::LegacyServerScript
-            | Middleware::LegacyClientScript
-            | Middleware::RunContextServerScript
-            | Middleware::RunContextClientScript => {
-                anyhow::bail!("syncback is not implemented for {self:?} yet")
-            }
         }
     }
 
@@ -330,6 +325,8 @@ impl Middleware {
                 | Middleware::ServerScriptDir
                 | Middleware::ClientScriptDir
                 | Middleware::ModuleScriptDir
+                | Middleware::LocalScriptDir
+                | Middleware::LegacyScriptDir
                 | Middleware::CsvDir
         )
     }
@@ -427,6 +424,10 @@ pub fn default_sync_rules() -> &'static [SyncRule] {
             sync_rule!("*.client.luau", ClientScript, ".client.luau"),
             sync_rule!("*.plugin.lua", PluginScript, ".plugin.lua"),
             sync_rule!("*.plugin.luau", PluginScript, ".plugin.luau"),
+            sync_rule!("*.legacy.lua", LegacyScript, ".legacy.lua"),
+            sync_rule!("*.legacy.luau", LegacyScript, ".legacy.luau"),
+            sync_rule!("*.local.lua", LocalScript, ".local.lua"),
+            sync_rule!("*.local.luau", LocalScript, ".local.luau"),
             sync_rule!("*.{lua,luau}", ModuleScript),
             sync_rule!("*.project.json", Project, ".project.json"),
             sync_rule!("*.project.jsonc", Project, ".project.jsonc"),

src/snapshot_middleware/project.rs

@@ -25,7 +25,7 @@ use crate::{
     RojoRef,
 };
 
-use super::{emit_legacy_scripts_default, snapshot_from_vfs};
+use super::snapshot_from_vfs;
 
 pub fn snapshot_project(
     context: &InstanceContext,
@@ -55,12 +55,6 @@ pub fn snapshot_project(
 
     context.add_sync_rules(sync_rules);
     context.add_path_ignore_rules(rules);
-    context.set_emit_legacy_scripts(
-        project
-            .emit_legacy_scripts
-            .or_else(emit_legacy_scripts_default)
-            .unwrap(),
-    );
 
     match snapshot_project_node(&context, path, project_name, &project.tree, vfs, None)? {
         Some(found_snapshot) => {

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__csv__test__csv_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__csv__test__csv_init.snap

@@ -20,8 +20,7 @@ metadata:
     - /root/init.meta.jsonc
     - /root/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__csv__test__csv_init_with_meta.snap

@@ -20,8 +20,7 @@ metadata:
     - /root/init.meta.jsonc
     - /root/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__csv__test__csv_with_meta.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__dir__test__empty_folder.snap

@@ -20,8 +20,7 @@ metadata:
     - /foo/init.meta.jsonc
     - /foo/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__dir__test__folder_in_folder.snap

@@ -20,8 +20,7 @@ metadata:
     - /foo/init.meta.jsonc
     - /foo/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~
@@ -47,8 +46,7 @@ children:
         - /foo/Child/init.meta.jsonc
         - /foo/Child/init.meta.json5
       context:
-        emit_legacy_scripts: true
+        decode_windows_invalid_chars: true
-        decode_windows_invalid_chars: false
       specified_id: ~
       middleware: dir
       schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__json__test__instance_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__json__test__with_metadata.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__json_model__test__model_from_vfs.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo.model.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~
@@ -26,8 +25,7 @@ children:
       ignore_unknown_instances: false
       relevant_paths: []
       context:
-        emit_legacy_scripts: true
+        decode_windows_invalid_chars: true
-        decode_windows_invalid_chars: false
       specified_id: ~
       middleware: ~
       schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__json_model__test__model_from_vfs_legacy.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo.model.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~
@@ -26,8 +25,7 @@ children:
       ignore_unknown_instances: false
       relevant_paths: []
       context:
-        emit_legacy_scripts: true
+        decode_windows_invalid_chars: true
-        decode_windows_invalid_chars: false
       specified_id: ~
       middleware: ~
       schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__class_script_disabled.snap

@@ -1,30 +0,0 @@
----
-source: src/snapshot_middleware/lua.rs
-expression: instance_snapshot
----
-snapshot_id: "00000000000000000000000000000000"
-metadata:
-  ignore_unknown_instances: false
-  instigating_source:
-    Path: /bar.server.lua
-  relevant_paths:
-    - /bar.server.lua
-    - /bar.meta.json
-    - /bar.meta.jsonc
-    - /bar.meta.json5
-  context:
-    emit_legacy_scripts: true
-    decode_windows_invalid_chars: false
-  specified_id: ~
-  middleware: ~
-  schema: ~
-name: bar
-class_name: Script
-properties:
-  Disabled:
-    Bool: true
-  RunContext:
-    Enum: 0
-  Source:
-    String: Hello there!
-children: []

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__class_script_with_meta.snap

@@ -1,28 +0,0 @@
----
-source: src/snapshot_middleware/lua.rs
-expression: instance_snapshot
----
-snapshot_id: "00000000000000000000000000000000"
-metadata:
-  ignore_unknown_instances: true
-  instigating_source:
-    Path: /foo.server.lua
-  relevant_paths:
-    - /foo.server.lua
-    - /foo.meta.json
-    - /foo.meta.jsonc
-    - /foo.meta.json5
-  context:
-    emit_legacy_scripts: true
-    decode_windows_invalid_chars: false
-  specified_id: ~
-  middleware: ~
-  schema: ~
-name: foo
-class_name: Script
-properties:
-  RunContext:
-    Enum: 0
-  Source:
-    String: Hello there!
-children: []

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__client_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: false
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__init_module_from_vfs.snap

@@ -20,8 +20,7 @@ metadata:
     - /root/init.meta.jsonc
     - /root/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__init_module_from_vfs_with_meta.snap

@@ -20,8 +20,7 @@ metadata:
     - /root/init.meta.jsonc
     - /root/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__legacy_from_vfs.snap

@@ -6,15 +6,14 @@ snapshot_id: "00000000000000000000000000000000"
 metadata:
   ignore_unknown_instances: false
   instigating_source:
-    Path: /foo.server.lua
+    Path: /foo.legacy.lua
   relevant_paths:
-    - /foo.server.lua
+    - /foo.legacy.lua
     - /foo.meta.json
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__local_from_vfs.snap

@@ -6,15 +6,14 @@ snapshot_id: "00000000000000000000000000000000"
 metadata:
   ignore_unknown_instances: false
   instigating_source:
-    Path: /foo.client.lua
+    Path: /foo.local.lua
   relevant_paths:
-    - /foo.client.lua
+    - /foo.local.lua
     - /foo.meta.json
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__module_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__module_with_meta.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__plugin_from_vfs.snap

@@ -0,0 +1,27 @@
+---
+source: src/snapshot_middleware/lua.rs
+expression: instance_snapshot
+---
+snapshot_id: "00000000000000000000000000000000"
+metadata:
+  ignore_unknown_instances: false
+  instigating_source:
+    Path: /foo.plugin.lua
+  relevant_paths:
+    - /foo.plugin.lua
+    - /foo.meta.json
+    - /foo.meta.jsonc
+    - /foo.meta.json5
+  context:
+    decode_windows_invalid_chars: true
+  specified_id: ~
+  middleware: ~
+  schema: ~
+name: foo
+class_name: Script
+properties:
+  RunContext:
+    Enum: 3
+  Source:
+    String: Hello there!
+children: []

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__runcontext_module_from_vfs.snap

@@ -1,26 +0,0 @@
----
-source: src/snapshot_middleware/lua.rs
-expression: instance_snapshot
----
-snapshot_id: "00000000000000000000000000000000"
-metadata:
-  ignore_unknown_instances: false
-  instigating_source:
-    Path: /foo.lua
-  relevant_paths:
-    - /foo.lua
-    - /foo.meta.json
-    - /foo.meta.jsonc
-    - /foo.meta.json5
-  context:
-    emit_legacy_scripts: false
-    decode_windows_invalid_chars: false
-  specified_id: ~
-  middleware: ~
-  schema: ~
-name: foo
-class_name: ModuleScript
-properties:
-  Source:
-    String: Hello there!
-children: []

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__runcontext_module_with_meta.snap

@@ -1,26 +0,0 @@
----
-source: src/snapshot_middleware/lua.rs
-expression: instance_snapshot
----
-snapshot_id: "00000000000000000000000000000000"
-metadata:
-  ignore_unknown_instances: true
-  instigating_source:
-    Path: /foo.lua
-  relevant_paths:
-    - /foo.lua
-    - /foo.meta.json
-    - /foo.meta.jsonc
-    - /foo.meta.json5
-  context:
-    emit_legacy_scripts: false
-    decode_windows_invalid_chars: false
-  specified_id: ~
-  middleware: ~
-  schema: ~
-name: foo
-class_name: ModuleScript
-properties:
-  Source:
-    String: Hello there!
-children: []

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__server_disabled.snap

@@ -13,8 +13,7 @@ metadata:
     - /bar.meta.jsonc
     - /bar.meta.json5
   context:
-    emit_legacy_scripts: false
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__server_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: false
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__lua__test__server_with_meta.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: false
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__meta_file__test__adjacent_read_json.snap

@@ -10,8 +10,7 @@ metadata:
     - /foo/bar.meta.jsonc
     - /foo/bar.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__meta_file__test__adjacent_read_jsonc.snap

@@ -10,8 +10,7 @@ metadata:
     - /foo/bar.meta.jsonc
     - /foo/bar.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__meta_file__test__directory_read_json.snap

@@ -10,8 +10,7 @@ metadata:
     - /foo/init.meta.jsonc
     - /foo/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__meta_file__test__directory_read_jsonc.snap

@@ -10,8 +10,7 @@ metadata:
     - /foo/init.meta.jsonc
     - /foo/init.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__no_name_project.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo/default.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_from_direct_file.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo/hello.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_path_property_overrides.snap

@@ -11,8 +11,7 @@ metadata:
     - /foo/other.project.json
     - /foo/default.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: project
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_with_children.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~
@@ -31,8 +30,7 @@ children:
           parent_class: Folder
       relevant_paths: []
       context:
-        emit_legacy_scripts: true
+        decode_windows_invalid_chars: true
-        decode_windows_invalid_chars: false
       specified_id: ~
       middleware: ~
       schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_with_path_to_project.snap

@@ -11,8 +11,7 @@ metadata:
     - /foo/other.project.json
     - /foo/default.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: project
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_with_path_to_project_with_children.snap

@@ -11,8 +11,7 @@ metadata:
     - /foo/other.project.json
     - /foo/default.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: project
   schema: ~
@@ -32,8 +31,7 @@ children:
           parent_class: Folder
       relevant_paths: []
       context:
-        emit_legacy_scripts: true
+        decode_windows_invalid_chars: true
-        decode_windows_invalid_chars: false
       specified_id: ~
       middleware: ~
       schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_with_path_to_txt.snap

@@ -14,8 +14,7 @@ metadata:
     - /foo/other.meta.json5
     - /foo/default.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: text
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_with_resolved_properties.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__project__test__project_with_unresolved_properties.snap

@@ -10,8 +10,7 @@ metadata:
   relevant_paths:
     - /foo.project.json
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__toml__test__instance_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__toml__test__with_metadata.snap

@@ -13,8 +13,7 @@ metadata:
     - foo.meta.jsonc
     - foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__txt__test__instance_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__txt__test__with_metadata.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__yaml__test__instance_from_vfs.snap

@@ -13,8 +13,7 @@ metadata:
     - /foo.meta.jsonc
     - /foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: ~
   middleware: ~
   schema: ~

src/snapshot_middleware/snapshots/librojo__snapshot_middleware__yaml__test__with_metadata.snap

@@ -13,8 +13,7 @@ metadata:
     - foo.meta.jsonc
     - foo.meta.json5
   context:
-    emit_legacy_scripts: true
+    decode_windows_invalid_chars: true
-    decode_windows_invalid_chars: false
   specified_id: manually specified
   middleware: ~
   schema: ~

src/snapshot_middleware/util.rs

@@ -48,8 +48,3 @@ where
             .with_context(|| format!("Path does not have a parent: {}", path.display()))
     }
 }
-
-// TEMP function until rojo 8.0, when it can be replaced with bool::default (aka false)
-pub fn emit_legacy_scripts_default() -> Option<bool> {
-    Some(true)
-}

src/syncback/file_names.rs

@@ -91,6 +91,8 @@ pub fn extension_for_middleware(middleware: Middleware) -> &'static str {
         Middleware::ClientScript => "client.luau",
         Middleware::ModuleScript => "luau",
         Middleware::PluginScript => "plugin.luau",
+        Middleware::LocalScript => "local.luau",
+        Middleware::LegacyScript => "legacy.luau",
         Middleware::Project => "project.json5",
         Middleware::Rbxm => "rbxm",
         Middleware::Rbxmx => "rbxmx",
@@ -98,12 +100,6 @@ pub fn extension_for_middleware(middleware: Middleware) -> &'static str {
         Middleware::Text => "txt",
         Middleware::Yaml => "yml",
 
-        Middleware::LegacyServerScript
-        | Middleware::LegacyClientScript
-        | Middleware::RunContextServerScript
-        | Middleware::RunContextClientScript => {
-            todo!("syncback does not work on the middleware {middleware:?} yet")
-        }
         // These are manually specified and not `_` to guard against future
         // middleware additions missing this function.
         Middleware::Ignore => unimplemented!("syncback does not work on Ignore middleware"),
@@ -111,7 +107,9 @@ pub fn extension_for_middleware(middleware: Middleware) -> &'static str {
         | Middleware::CsvDir
         | Middleware::ServerScriptDir
         | Middleware::ClientScriptDir
-        | Middleware::ModuleScriptDir => {
+        | Middleware::ModuleScriptDir
+        | Middleware::LocalScriptDir
+        | Middleware::LegacyScriptDir => {
             unimplemented!("directory middleware requires special treatment")
         }
     }

src/syncback/mod.rs

@@ -325,8 +325,21 @@ pub fn get_best_middleware(snapshot: &SyncbackSnapshot) -> Middleware {
             "Folder" | "Configuration" | "Tool" | "ScreenGui" | "SurfaceGui" | "BillboardGui"
             | "AdGui" => Middleware::Dir,
             "StringValue" => Middleware::Text,
-            "Script" => Middleware::ServerScript,
+            "Script" => {
-            "LocalScript" => Middleware::ClientScript,
+                // Check RunContext to determine which middleware to use
+                // RunContext enum values: Legacy = 0, Server = 1, Client = 2, Plugin = 3
+                match inst.properties.get(&ustr("RunContext")) {
+                    Some(Variant::Enum(e)) => match e.to_u32() {
+                        0 => Middleware::LegacyScript,
+                        1 => Middleware::ServerScript,
+                        2 => Middleware::ClientScript,
+                        3 => Middleware::PluginScript,
+                        _ => Middleware::LegacyScript, // Unknown RunContext, default to Legacy
+                    },
+                    _ => Middleware::LegacyScript, // No RunContext property, default to Legacy
+                }
+            }
+            "LocalScript" => Middleware::LocalScript,
             "ModuleScript" => Middleware::ModuleScript,
             "LocalizationTable" => Middleware::Csv,
             // Default: use JsonModel for everything else (becomes Dir if has children)
@@ -339,6 +352,9 @@ pub fn get_best_middleware(snapshot: &SyncbackSnapshot) -> Middleware {
             Middleware::ServerScript => Middleware::ServerScriptDir,
             Middleware::ClientScript => Middleware::ClientScriptDir,
             Middleware::ModuleScript => Middleware::ModuleScriptDir,
+            Middleware::PluginScript => Middleware::ServerScriptDir, // Plugin scripts with children use server script dir for now
+            Middleware::LegacyScript => Middleware::LegacyScriptDir,
+            Middleware::LocalScript => Middleware::LocalScriptDir,
             Middleware::Csv => Middleware::CsvDir,
             Middleware::JsonModel | Middleware::Text => Middleware::Dir,
             _ => middleware,
@@ -431,11 +447,11 @@ impl SyncbackRules {
         Ok(globs)
     }
 
-    /// Returns whether Windows-invalid characters should be encoded in file
+    /// Returns whether special characters (including periods) should be encoded
-    /// names during syncback. Defaults to `false`.
+    /// in file names during syncback. Defaults to `true`.
     #[inline]
     pub fn encode_windows_invalid_chars(&self) -> bool {
-        self.encode_windows_invalid_chars.unwrap_or(false)
+        self.encode_windows_invalid_chars.unwrap_or(true)
     }
 }
 

src/web/api.rs

@@ -257,6 +257,54 @@ impl ApiService {
     /// Syncback an added instance by creating a file in the filesystem.
     /// The file watcher will pick up the change and update Rojo's tree.
     ///
+    /// Checks if a path in the Rojo tree is unique by verifying no duplicates exist
+    /// at ANY level of the path (similar to ref_properties::is_path_unique).
+    /// Returns true if the path is unique, false if duplicates exist at any level.
+    fn is_tree_path_unique(&self, tree: &crate::snapshot::RojoTree, target_ref: Ref) -> bool {
+        let mut current_ref = target_ref;
+
+        loop {
+            let current = match tree.get_instance(current_ref) {
+                Some(inst) => inst,
+                None => return false,
+            };
+
+            let parent_ref = current.parent();
+            if parent_ref.is_none() {
+                // Reached root - path is unique at all levels
+                return true;
+            }
+
+            let parent = match tree.get_instance(parent_ref) {
+                Some(inst) => inst,
+                None => return true,
+            };
+
+            // Check if any sibling has the same name as current
+            let current_name = current.name();
+            let mut count = 0;
+            for child_ref in parent.children() {
+                if let Some(child) = tree.get_instance(*child_ref) {
+                    if child.name() == current_name {
+                        count += 1;
+                        if count > 1 {
+                            // Duplicate found at this level - path is not unique
+                            log::warn!(
+                                "Syncback: Path to '{}' is not unique - duplicate-named siblings at '{}'",
+                                current_name,
+                                parent.name()
+                            );
+                            return false;
+                        }
+                    }
+                }
+            }
+
+            // Move up to parent and check the next level
+            current_ref = parent_ref;
+        }
+    }
+
     /// This follows the same middleware selection logic as the dedicated syncback
     /// system in `src/syncback/mod.rs` to ensure consistent behavior.
     fn syncback_added_instance(
@@ -280,6 +328,14 @@ impl ApiService {
             .get_instance(added.parent)
             .context("Parent instance not found in Rojo tree")?;
 
+        // Check if the parent path is unique (no duplicate-named siblings at any level)
+        if !self.is_tree_path_unique(&tree, added.parent) {
+            anyhow::bail!(
+                "Cannot sync instance '{}' - parent path contains duplicate-named siblings",
+                added.name
+            );
+        }
+
         // Get the parent's filesystem path from its metadata
         let parent_path = parent_instance
             .metadata()
@@ -302,6 +358,54 @@ impl ApiService {
         self.syncback_instance_to_path(added, &parent_dir)
     }
 
+    /// Check for duplicate names among children and return the set of unique children
+    /// that should be synced. Logs warnings for skipped duplicates.
+    fn filter_duplicate_children<'a>(
+        &self,
+        children: &'a [crate::web::interface::AddedInstance],
+    ) -> Vec<&'a crate::web::interface::AddedInstance> {
+        use std::collections::HashMap;
+
+        // Count occurrences of each name
+        let mut name_counts: HashMap<&str, usize> = HashMap::new();
+        for child in children {
+            *name_counts.entry(&child.name).or_insert(0) += 1;
+        }
+
+        // Find duplicates
+        let duplicates: std::collections::HashSet<&str> = name_counts
+            .iter()
+            .filter(|(_, &count)| count > 1)
+            .map(|(&name, _)| name)
+            .collect();
+
+        // Log skipped duplicates
+        let mut skipped_count = 0;
+        for child in children {
+            if duplicates.contains(child.name.as_str()) {
+                log::warn!(
+                    "Syncback: Skipped instance '{}' ({}) - has duplicate-named siblings (cannot reliably sync)",
+                    child.name,
+                    child.class_name
+                );
+                skipped_count += 1;
+            }
+        }
+
+        if skipped_count > 0 {
+            log::warn!(
+                "Syncback: Skipped {} instance(s) with duplicate-named siblings",
+                skipped_count
+            );
+        }
+
+        // Return only non-duplicate children
+        children
+            .iter()
+            .filter(|child| !duplicates.contains(child.name.as_str()))
+            .collect()
+    }
+
     /// Recursively syncback an instance and its children to the filesystem.
     /// This is the internal implementation that handles the actual file creation.
     fn syncback_instance_to_path(
@@ -320,7 +424,9 @@ impl ApiService {
             )
         })?;
 
-        let has_children = !added.children.is_empty();
+        // Filter out children with duplicate names (cannot reliably sync)
+        let unique_children = self.filter_duplicate_children(&added.children);
+        let has_children = !unique_children.is_empty();
 
         // Determine the appropriate middleware/file format based on class name
         // This matches the logic in src/syncback/mod.rs::get_best_middleware
@@ -345,7 +451,7 @@ impl ApiService {
                         "Syncback: Created ModuleScript directory at {}",
                         dir_path.display()
                     );
-                    for child in &added.children {
+                    for child in &unique_children {
                         self.syncback_instance_to_path(child, &dir_path)?;
                     }
                 } else {
@@ -378,7 +484,7 @@ impl ApiService {
                         "Syncback: Created Script directory at {}",
                         dir_path.display()
                     );
-                    for child in &added.children {
+                    for child in &unique_children {
                         self.syncback_instance_to_path(child, &dir_path)?;
                     }
                 } else {
@@ -399,7 +505,7 @@ impl ApiService {
                     fs::create_dir_all(&dir_path).with_context(|| {
                         format!("Failed to create directory: {}", dir_path.display())
                     })?;
-                    let init_path = dir_path.join("init.client.luau");
+                    let init_path = dir_path.join("init.local.luau");
                     fs::write(&init_path, source.as_bytes()).with_context(|| {
                         format!("Failed to write file: {}", init_path.display())
                     })?;
@@ -408,11 +514,11 @@ impl ApiService {
                         "Syncback: Created LocalScript directory at {}",
                         dir_path.display()
                     );
-                    for child in &added.children {
+                    for child in &unique_children {
                         self.syncback_instance_to_path(child, &dir_path)?;
                     }
                 } else {
-                    let file_path = parent_dir.join(format!("{}.client.luau", added.name));
+                    let file_path = parent_dir.join(format!("{}.local.luau", added.name));
                     fs::write(&file_path, source.as_bytes()).with_context(|| {
                         format!("Failed to write file: {}", file_path.display())
                     })?;
@@ -439,7 +545,8 @@ impl ApiService {
                 };
 
                 // Add .gitkeep for empty directories with no metadata (matches dedicated syncback)
-                if added.children.is_empty() && !has_metadata {
+                // Uses !has_children which accounts for filtered duplicate children
+                if !has_children && !has_metadata {
                     fs::write(dir_path.join(".gitkeep"), b"")
                         .with_context(|| "Failed to write .gitkeep")?;
                 }
@@ -451,7 +558,7 @@ impl ApiService {
                 );
 
                 // Recursively process children
-                for child in &added.children {
+                for child in &unique_children {
                     self.syncback_instance_to_path(child, &dir_path)?;
                 }
             }
@@ -469,7 +576,7 @@ impl ApiService {
                         "Syncback: Created StringValue directory at {}",
                         dir_path.display()
                     );
-                    for child in &added.children {
+                    for child in &unique_children {
                         self.syncback_instance_to_path(child, &dir_path)?;
                     }
                 } else {
@@ -508,7 +615,7 @@ impl ApiService {
                         "Syncback: Created LocalizationTable directory at {}",
                         dir_path.display()
                     );
-                    for child in &added.children {
+                    for child in &unique_children {
                         self.syncback_instance_to_path(child, &dir_path)?;
                     }
                 } else {
@@ -542,7 +649,7 @@ impl ApiService {
                     );
 
                     // Recursively process children
-                    for child in &added.children {
+                    for child in &unique_children {
                         self.syncback_instance_to_path(child, &dir_path)?;
                     }
                 } else {
@@ -752,11 +859,9 @@ impl ApiService {
     /// For `Script` class:
     /// - RunContext: Client → "client"
     /// - RunContext: Server → "server"
-    /// - RunContext: Legacy → "server" (default for legacy mode)
+    /// - RunContext: Legacy → "legacy"
     /// - RunContext: Plugin → "plugin"
-    /// - No RunContext → "server" (default)
+    /// - No RunContext → "legacy" (default)
-    ///
-    /// This ensures proper round-tripping regardless of emitLegacyScripts mode.
     fn get_script_suffix_for_run_context(
         &self,
         added: &crate::web::interface::AddedInstance,
@@ -779,16 +884,16 @@ impl ApiService {
                     return match name.as_ref() {
                         "Client" => "client",
                         "Server" => "server",
-                        "Legacy" => "server",
+                        "Legacy" => "legacy",
                         "Plugin" => "plugin",
-                        _ => "server",
+                        _ => "legacy",
                     };
                 }
             }
         }
 
-        // Default to server if no RunContext or unrecognized
+        // Default to legacy if no RunContext or unrecognized
-        "server"
+        "legacy"
     }
 
     /// Write an adjacent meta file for scripts without children.
@@ -1596,15 +1701,13 @@ mod tests {
             // Test that script class names result in correct file extensions
             let test_cases = vec![
                 ("ModuleScript", "TestModule", "TestModule.luau"),
-                ("Script", "TestScript", "TestScript.server.luau"),
+                ("LocalScript", "TestClient", "TestClient.local.luau"),
-                ("LocalScript", "TestClient", "TestClient.client.luau"),
             ];
 
             for (class_name, name, expected) in test_cases {
                 let file_name = match class_name {
                     "ModuleScript" => format!("{}.luau", name),
-                    "Script" => format!("{}.server.luau", name),
+                    "LocalScript" => format!("{}.local.luau", name),
-                    "LocalScript" => format!("{}.client.luau", name),
                     _ => format!("{}.model.json", name),
                 };
                 assert_eq!(
@@ -1758,8 +1861,8 @@ mod tests {
         }
 
         #[test]
-        fn test_run_context_legacy_gives_server_suffix() {
+        fn test_run_context_legacy_gives_legacy_suffix() {
-            // Script with RunContext: Legacy should produce .server.luau (for legacy mode)
+            // Script with RunContext: Legacy should produce .legacy.luau
             let run_context_enums = rbx_reflection_database::get()
                 .ok()
                 .and_then(|db| db.enums.get("RunContext"))
@@ -1792,14 +1895,13 @@ mod tests {
             // For Script class, the file suffix is determined by RunContext:
             // - Client → .client.luau
             // - Server → .server.luau
-            // - Legacy → .server.luau
+            // - Legacy → .legacy.luau
             // - Plugin → .plugin.luau
-            // This allows proper round-tripping regardless of emitLegacyScripts mode
 
             let expected_mappings = vec![
                 ("Client", "client"),
                 ("Server", "server"),
-                ("Legacy", "server"),
+                ("Legacy", "legacy"),
                 ("Plugin", "plugin"),
             ];
 
@@ -1807,9 +1909,9 @@ mod tests {
                 let suffix = match run_context {
                     "Client" => "client",
                     "Server" => "server",
-                    "Legacy" => "server",
+                    "Legacy" => "legacy",
                     "Plugin" => "plugin",
-                    _ => "server",
+                    _ => "legacy",
                 };
                 assert_eq!(
                     suffix, expected_suffix,
@@ -1820,14 +1922,14 @@ mod tests {
         }
 
         #[test]
-        fn test_local_script_always_client() {
+        fn test_local_script_always_local() {
-            // LocalScript class always produces .client.luau regardless of any properties
+            // LocalScript class always produces .local.luau regardless of any properties
             let class_name = "LocalScript";
-            let expected_suffix = "client";
+            let expected_suffix = "local";
 
-            // LocalScript doesn't check RunContext - it's always client
+            // LocalScript doesn't check RunContext - it's always local
             let suffix = if class_name == "LocalScript" {
-                "client"
+                "local"
             } else {
                 "unknown"
             };
@@ -2136,8 +2238,6 @@ mod tests {
     // =========================================================================
     mod run_context_comprehensive_tests {
         use super::*;
-        use rbx_dom_weak::types::Enum;
-        use std::collections::HashMap;
 
         /// Helper to get RunContext enum value by name
         fn get_run_context_value(name: &str) -> Option<u32> {
@@ -2817,7 +2917,7 @@ mod tests {
             // In scripts-only mode, all instances get ignoreUnknownInstances: true
             // This prevents accidental deletion of non-script instances
             let folder = "Folder";
-            let is_script = is_script_class(folder);
+            let _is_script = is_script_class(folder);
 
             // Non-scripts should have ignoreUnknownInstances set
             let should_set_ignore = true; // All instances in scripts-only mode
@@ -2868,18 +2968,18 @@ mod tests {
                     expected_extension: ".luau",
                     description: "ModuleScript without RunContext",
                 },
-                // LocalScript - always .client.luau
+                // LocalScript - always .local.luau
                 TestCase {
                     class_name: "LocalScript",
                     run_context: None,
-                    expected_extension: ".client.luau",
+                    expected_extension: ".local.luau",
                     description: "LocalScript",
                 },
                 // Script with various RunContext values
                 TestCase {
                     class_name: "Script",
                     run_context: None,
-                    expected_extension: ".server.luau",
+                    expected_extension: ".legacy.luau",
                     description: "Script without RunContext (default)",
                 },
                 TestCase {
@@ -2897,7 +2997,7 @@ mod tests {
                 TestCase {
                     class_name: "Script",
                     run_context: Some("Legacy"),
-                    expected_extension: ".server.luau",
+                    expected_extension: ".legacy.luau",
                     description: "Script with RunContext::Legacy",
                 },
                 TestCase {
@@ -2911,16 +3011,16 @@ mod tests {
             for case in test_cases {
                 let suffix = match case.class_name {
                     "ModuleScript" => String::new(),
-                    "LocalScript" => "client".to_string(),
+                    "LocalScript" => "local".to_string(),
                     "Script" => {
                         // Match on RunContext name to determine suffix
                         match case.run_context {
                             Some("Client") => "client",
                             Some("Server") => "server",
-                            Some("Legacy") => "server",
+                            Some("Legacy") => "legacy",
                             Some("Plugin") => "plugin",
-                            None => "server",
+                            None => "legacy",
-                            _ => "server",
+                            _ => "legacy",
                         }
                         .to_string()
                     }
@@ -3003,4 +3103,472 @@ mod tests {
             }
         }
     }
+
+    // =========================================================================
+    // Duplicate Path Detection Tests
+    // =========================================================================
+    mod duplicate_path_tests {
+        // Helper to simulate sibling name checking
+        fn has_duplicate_sibling_names(names: &[&str], target_name: &str) -> bool {
+            let count = names.iter().filter(|&&n| n == target_name).count();
+            count > 1
+        }
+
+        // Simulates the duplicate children filter logic
+        fn filter_duplicate_names<'a>(names: &[&'a str]) -> Vec<&'a str> {
+            let mut counts: std::collections::HashMap<&str, usize> =
+                std::collections::HashMap::new();
+            for name in names {
+                *counts.entry(name).or_insert(0) += 1;
+            }
+
+            names
+                .iter()
+                .filter(|&&name| counts.get(name).copied().unwrap_or(0) <= 1)
+                .copied()
+                .collect()
+        }
+
+        #[test]
+        fn test_no_duplicates_all_pass() {
+            let names = vec!["Script1", "Script2", "Script3", "Folder"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(filtered.len(), 4, "All unique names should pass");
+        }
+
+        #[test]
+        fn test_duplicate_siblings_filtered() {
+            let names = vec!["Script", "Script", "Other"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Duplicate 'Script' entries should be filtered"
+            );
+            assert_eq!(filtered[0], "Other", "Only 'Other' should remain");
+        }
+
+        #[test]
+        fn test_multiple_duplicates_filtered() {
+            let names = vec!["A", "A", "B", "B", "C"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(filtered.len(), 1, "Only unique 'C' should remain");
+            assert_eq!(filtered[0], "C");
+        }
+
+        #[test]
+        fn test_all_duplicates_empty_result() {
+            let names = vec!["Same", "Same", "Same"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                0,
+                "All duplicates should result in empty list"
+            );
+        }
+
+        #[test]
+        fn test_sibling_detection_positive() {
+            let siblings = vec!["Script", "Script", "Other"];
+            assert!(
+                has_duplicate_sibling_names(&siblings, "Script"),
+                "'Script' should be detected as having duplicate siblings"
+            );
+        }
+
+        #[test]
+        fn test_sibling_detection_negative() {
+            let siblings = vec!["Script", "Folder", "Model"];
+            assert!(
+                !has_duplicate_sibling_names(&siblings, "Script"),
+                "'Script' should NOT be detected as duplicate with unique siblings"
+            );
+        }
+
+        #[test]
+        fn test_sibling_detection_not_in_list() {
+            let siblings = vec!["A", "B", "C"];
+            assert!(
+                !has_duplicate_sibling_names(&siblings, "D"),
+                "'D' not in list should not have duplicates"
+            );
+        }
+
+        #[test]
+        fn test_path_uniqueness_concept() {
+            // Test the concept: path is unique only if NO level has duplicates
+            //
+            // Tree:
+            // Root
+            //   ├─ FolderA
+            //   │    └─ Script
+            //   └─ FolderA (duplicate!)
+            //        └─ Script
+            //
+            // Path "Root/FolderA/Script" is NOT unique because FolderA is duplicated
+
+            let root_children = vec!["FolderA", "FolderA"];
+            let folder_children = vec!["Script"];
+
+            // Check at root level - duplicates exist
+            let has_dup_at_root = has_duplicate_sibling_names(&root_children, "FolderA");
+            assert!(
+                has_dup_at_root,
+                "FolderA should be detected as duplicate at root level"
+            );
+
+            // Check at folder level - no duplicates
+            let has_dup_at_folder = has_duplicate_sibling_names(&folder_children, "Script");
+            assert!(
+                !has_dup_at_folder,
+                "Script has no duplicate siblings within its parent"
+            );
+
+            // But the PATH is still not unique because of the ancestor duplicate
+            let path_is_unique = !has_dup_at_root;
+            assert!(
+                !path_is_unique,
+                "Path should NOT be unique due to ancestor duplicate"
+            );
+        }
+
+        #[test]
+        fn test_path_uniqueness_deep_hierarchy() {
+            // Tree:
+            // Root (unique)
+            //   └─ Level1 (unique)
+            //        └─ Level2 (has duplicate sibling)
+            //             └─ Target
+            //
+            // Path to Target is NOT unique
+
+            let level1_children = vec!["Level2", "Level2", "Other"];
+            let level2_children = vec!["Target"];
+
+            let has_dup_at_level1 = has_duplicate_sibling_names(&level1_children, "Level2");
+            assert!(has_dup_at_level1, "Level2 has duplicate at Level1");
+
+            // Even though Target itself has no duplicates, path is not unique
+            let has_dup_at_level2 = has_duplicate_sibling_names(&level2_children, "Target");
+            assert!(!has_dup_at_level2, "Target has no duplicate at Level2");
+
+            // Path uniqueness requires ALL levels to be unique
+            let path_unique = !has_dup_at_level1 && !has_dup_at_level2;
+            assert!(
+                !path_unique,
+                "Path should NOT be unique due to Level2 duplicate"
+            );
+        }
+
+        #[test]
+        fn test_path_uniqueness_fully_unique() {
+            // Tree:
+            // Root
+            //   └─ Folder (unique)
+            //        └─ SubFolder (unique)
+            //             └─ Script (unique)
+
+            let root_children = vec!["Folder"];
+            let folder_children = vec!["SubFolder"];
+            let sub_children = vec!["Script"];
+
+            let root_unique = !has_duplicate_sibling_names(&root_children, "Folder");
+            let folder_unique = !has_duplicate_sibling_names(&folder_children, "SubFolder");
+            let sub_unique = !has_duplicate_sibling_names(&sub_children, "Script");
+
+            let path_unique = root_unique && folder_unique && sub_unique;
+            assert!(
+                path_unique,
+                "Path should be unique when all levels are unique"
+            );
+        }
+
+        #[test]
+        fn test_case_sensitive_duplicates() {
+            // Roblox names are case-sensitive, so "Script" and "script" are different
+            let names = vec!["Script", "script", "SCRIPT"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                3,
+                "Case-different names should all be kept (case-sensitive)"
+            );
+        }
+
+        #[test]
+        fn test_empty_names_handled() {
+            let names = vec!["", "", "Valid"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Empty string duplicates should be filtered"
+            );
+            assert_eq!(filtered[0], "Valid");
+        }
+
+        #[test]
+        fn test_special_characters_in_names() {
+            // Names with special characters that might cause filesystem issues
+            // are handled separately by validate_file_name, but duplicates should still work
+            let names = vec!["Script (1)", "Script (2)", "Script (1)"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Only 'Script (2)' should remain after filtering duplicates"
+            );
+            assert_eq!(filtered[0], "Script (2)");
+        }
+
+        #[test]
+        fn test_whitespace_names() {
+            // Names with leading/trailing whitespace are technically different
+            let names = vec!["Script", " Script", "Script "];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                3,
+                "Whitespace-different names should all be kept"
+            );
+        }
+
+        // =====================================================================
+        // Non-Script Duplicate Tests - Duplicates apply to ALL instance types
+        // =====================================================================
+
+        #[test]
+        fn test_duplicate_folders_filtered() {
+            // Duplicate Folders should be filtered just like scripts
+            let names = vec!["MyFolder", "MyFolder", "OtherFolder"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(filtered.len(), 1, "Duplicate 'MyFolder' should be filtered");
+            assert_eq!(filtered[0], "OtherFolder");
+        }
+
+        #[test]
+        fn test_duplicate_parts_filtered() {
+            // Duplicate Parts should be filtered
+            let names = vec!["Part", "Part", "Baseplate"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(filtered.len(), 1, "Duplicate 'Part' should be filtered");
+            assert_eq!(filtered[0], "Baseplate");
+        }
+
+        #[test]
+        fn test_duplicate_models_filtered() {
+            // Duplicate Models should be filtered
+            let names = vec!["Car", "Car", "House"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Duplicate 'Car' models should be filtered"
+            );
+        }
+
+        #[test]
+        fn test_duplicate_values_filtered() {
+            // Duplicate IntValues/StringValues should be filtered
+            let names = vec!["Score", "Score", "Health"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Duplicate 'Score' values should be filtered"
+            );
+        }
+
+        #[test]
+        fn test_duplicate_gui_elements_filtered() {
+            // Duplicate GUI elements should be filtered
+            let names = vec!["MainFrame", "MainFrame", "Sidebar"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Duplicate 'MainFrame' GUI should be filtered"
+            );
+        }
+
+        #[test]
+        fn test_mixed_types_same_name_filtered() {
+            // Even if types differ, same names are duplicates (filesystem perspective)
+            // E.g., a Folder named "Data" and a Script named "Data" would conflict
+            let names = vec!["Data", "Data"]; // Could be Folder + Script
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                0,
+                "Same-named instances of different types still conflict"
+            );
+        }
+
+        #[test]
+        fn test_folder_hierarchy_duplicates() {
+            // Duplicates in folder hierarchies
+            // Root/
+            //   ├─ Enemies/
+            //   │    └─ Enemy (unique)
+            //   └─ Enemies/ (duplicate!)
+            //        └─ Enemy
+
+            let root_children = vec!["Enemies", "Enemies", "Players"];
+            let enemies_unique = !has_duplicate_sibling_names(&root_children, "Enemies");
+            assert!(
+                !enemies_unique,
+                "Duplicate 'Enemies' folders should be detected"
+            );
+        }
+
+        #[test]
+        fn test_part_ancestor_duplicates() {
+            // A Part deep in hierarchy with duplicate ancestor
+            // Workspace/
+            //   ├─ Zone/
+            //   │    └─ SpawnPoint (Part)
+            //   └─ Zone/ (duplicate!)
+            //        └─ SpawnPoint (Part)
+
+            let workspace_children = vec!["Zone", "Zone"];
+            let zone_unique = !has_duplicate_sibling_names(&workspace_children, "Zone");
+            assert!(
+                !zone_unique,
+                "Duplicate 'Zone' ancestors make Part paths ambiguous"
+            );
+        }
+
+        #[test]
+        fn test_remote_event_duplicates() {
+            // RemoteEvents with duplicate names
+            let names = vec!["FireBullet", "FireBullet", "TakeDamage"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Duplicate RemoteEvents should be filtered"
+            );
+        }
+
+        #[test]
+        fn test_configuration_duplicates() {
+            // Configuration instances with duplicates
+            let names = vec!["Settings", "Settings", "Config"];
+            let filtered = filter_duplicate_names(&names);
+            assert_eq!(
+                filtered.len(),
+                1,
+                "Duplicate Configurations should be filtered"
+            );
+        }
+    }
+
+    // =========================================================================
+    // Duplicate Path Detection - Integration Scenarios
+    // =========================================================================
+    mod duplicate_path_integration_tests {
+
+        #[test]
+        fn test_syncback_skips_duplicate_children() {
+            // When syncing back children, duplicates should be skipped
+            // This test verifies the filter_duplicate_children logic
+
+            let children_names = vec!["ChildA", "ChildB", "ChildA", "ChildC"];
+            let unique: Vec<_> = children_names
+                .iter()
+                .filter(|&&name| children_names.iter().filter(|&&n| n == name).count() == 1)
+                .collect();
+
+            assert_eq!(unique.len(), 2, "ChildB and ChildC should be kept");
+            assert!(unique.contains(&&"ChildB"));
+            assert!(unique.contains(&&"ChildC"));
+        }
+
+        #[test]
+        fn test_recursive_duplicate_handling() {
+            // Test that duplicates at any level are handled
+            //
+            // Parent/
+            //   ├─ Child1/
+            //   │    ├─ GrandChild (duplicate)
+            //   │    └─ GrandChild (duplicate)
+            //   └─ Child2/
+            //        └─ GrandChild (unique within its parent)
+
+            let child1_grandchildren = vec!["GrandChild", "GrandChild"];
+            let child2_grandchildren = vec!["GrandChild"];
+
+            // Child1's grandchildren have duplicates
+            let child1_filtered: Vec<_> = child1_grandchildren
+                .iter()
+                .filter(|&&name| child1_grandchildren.iter().filter(|&&n| n == name).count() == 1)
+                .collect();
+            assert_eq!(
+                child1_filtered.len(),
+                0,
+                "Child1's duplicate grandchildren filtered"
+            );
+
+            // Child2's grandchild is unique
+            let child2_filtered: Vec<_> = child2_grandchildren
+                .iter()
+                .filter(|&&name| child2_grandchildren.iter().filter(|&&n| n == name).count() == 1)
+                .collect();
+            assert_eq!(child2_filtered.len(), 1, "Child2's unique grandchild kept");
+        }
+
+        #[test]
+        fn test_duplicate_log_message_format() {
+            // Verify the expected log message format for skipped duplicates
+            let class_name = "ModuleScript";
+            let full_name = "game.ReplicatedStorage.DuplicateScript";
+
+            let expected_msg = format!(
+                "Skipped instance '{}' ({}) - path contains duplicate-named siblings (cannot reliably sync)",
+                full_name, class_name
+            );
+
+            assert!(expected_msg.contains(full_name));
+            assert!(expected_msg.contains(class_name));
+            assert!(expected_msg.contains("duplicate-named siblings"));
+        }
+
+        #[test]
+        fn test_parent_path_validation() {
+            // When pulling an instance, we must verify the parent path is unique
+            // This simulates the is_tree_path_unique check
+
+            // Scenario: Trying to add a script under a folder that has duplicate siblings
+            let parent_path_levels = vec![
+                ("Root", vec!["FolderA", "FolderA"]), // Duplicate at this level!
+            ];
+
+            let path_unique = parent_path_levels
+                .iter()
+                .all(|(target, siblings)| siblings.iter().filter(|&&s| s == *target).count() == 1);
+
+            assert!(
+                !path_unique,
+                "Parent path with duplicates should fail validation"
+            );
+        }
+
+        #[test]
+        fn test_valid_parent_path() {
+            // Valid parent path with no duplicates at any level
+            let parent_path_levels = vec![
+                (
+                    "ReplicatedStorage",
+                    vec!["Workspace", "ReplicatedStorage", "ServerStorage"],
+                ),
+                ("Shared", vec!["Shared", "Client", "Server"]),
+            ];
+
+            let path_unique = parent_path_levels
+                .iter()
+                .all(|(target, siblings)| siblings.iter().filter(|&&s| s == *target).count() == 1);
+
+            assert!(path_unique, "Valid parent path should pass validation");
+        }
+    }
 }

tests/tests/build.rs

@@ -44,7 +44,6 @@ gen_build_tests! {
     json_model_legacy_name,
     module_in_folder,
     module_init,
-    nested_runcontext,
     optional,
     project_composed_default,
     project_composed_file,