From fb30f845963fca2b160547ab32c46b640792a23e Mon Sep 17 00:00:00 2001
From: ernisto <joaovitordesouza707@gmail.com>
Date: Thu, 10 Apr 2025 21:06:35 -0300
Subject: [PATCH] feat: derive no longer run twice

---
 src/graph.luau  | 61 +++++++++++++++----------------------------------
 test/tests.luau | 26 ++++++++++-----------
 2 files changed, 31 insertions(+), 56 deletions(-)

diff --git a/src/graph.luau b/src/graph.luau
index 0f0e0d1..8baa7bc 100644
--- a/src/graph.luau
+++ b/src/graph.luau
@@ -163,53 +163,28 @@ local update_queue = { n = 0 } :: { n: number, [number]: Node<any> }
 
 local function evaluate_node<T>(node: Node<T>)
     if node.higher_parent_update_id == node.last_eval_update_id then return node.needs_queue_children end
-    if flags.strict then
-        local initial_value = node.cache
+    local cur_value = node.cache
 
-        for i = 1, 2 do
-            local cur_value = node.cache
+    flush_cleanups(node)
+    destroy_owned(node)
 
-            flush_cleanups(node)
-            destroy_owned(node)
-    
-            push_scope(node)
-            local ok, new_value = ycall(node.effect :: (T) -> T, cur_value)
-            pop_scope()
-            
-            if not ok then
-                table.clear(update_queue)
-                update_queue.n = 0
-                error(`effect error stacktrace\n{new_value :: string}`, 0)
-            end
+    push_scope(node)
+    local ok, new_value = (if flags.strict then ycall else pcall :: any)(node.effect :: (T) -> T, node.cache)
+    pop_scope()
 
-            node.cache = new_value :: T
-        end
-
-        local needs_queue_children = not is_similar(initial_value, node.cache)
-        node.needs_queue_children = needs_queue_children
-        node.last_eval_update_id = update_id
-        return needs_queue_children
-    else
-        local cur_value = node.cache
-
-        flush_cleanups(node)
-        destroy_owned(node)
-
-        push_scope(node)
-        local ok, new_value = pcall(node.effect :: (T) -> T, node.cache)
-        pop_scope()
-
-        if not ok then
-            table.clear(update_queue)
-            update_queue.n = 0
-            error(`effect error:\n{new_value}\n`, 0)
-        end
-        local needs_queue_children = not is_similar(cur_value, new_value)
-        node.needs_queue_children = needs_queue_children
-        node.last_eval_update_id = update_id
-        node.cache = new_value
-        return needs_queue_children
+    if not ok then
+        table.clear(update_queue)
+        update_queue.n = 0
+        error(`effect error:\n{new_value}`, 0)
     end
+
+    local needs_queue_children = not is_similar(cur_value, new_value)
+    node.needs_queue_children = needs_queue_children
+
+    node.last_eval_update_id = update_id
+    node.cache = new_value
+    
+    return needs_queue_children
 end
 
 local function queue_children_for_update<T>(node: SourceNode<T>)
diff --git a/test/tests.luau b/test/tests.luau
index 4b50483..db6d069 100644
--- a/test/tests.luau
+++ b/test/tests.luau
@@ -1221,24 +1221,24 @@ TEST("show()", wrap_root(function()
 
         branch = 1
         weapon { id = "1", enchant = "fire" }
-        CHECK(count == 8)
+        CHECK(count == 1)
 
         branch = 2
         weapon { id = "1", enchant = "poison" }
-        CHECK(count == 10)
+        CHECK(count == 2)
 
         weapon { id = "1", enchant = nil }
-        CHECK(count == 10)
+        CHECK(count == 2)
 
         branch = 1
         weapon { id = "1", enchant = "fire" }
-        CHECK(count == 14)
+        CHECK(count == 3)
 
         weapon(nil)
 
         branch = 2
         weapon { id = "1", enchant = "poison" }
-        CHECK(count == 22)
+        CHECK(count == 4)
 
         vide.strict = false
     end
@@ -2763,9 +2763,9 @@ TEST("strict", wrap_root(function()
             return src()
         end)
 
-        CHECK(count == 2)
+        CHECK(count == 1)
         src(2)
-        CHECK(count == 4)
+        CHECK(count == 2)
     end
 
     do CASE "run effect callback twice"
@@ -2777,9 +2777,9 @@ TEST("strict", wrap_root(function()
             src()
         end)
 
-        CHECK(count == 2)
+        CHECK(count == 1)
         src(2)
-        CHECK(count == 4)
+        CHECK(count == 2)
     end
 
     do CASE "indexes() error if primitive"
@@ -2841,9 +2841,9 @@ TEST("strict", wrap_root(function()
             return count
         end, count)
 
-        CHECK(count == 2)
+        CHECK(count == 1)
         src(not src())
-        CHECK(count == 4)
+        CHECK(count == 2)
     end
 
     do CASE "effect using derived source"
@@ -2860,11 +2860,11 @@ TEST("strict", wrap_root(function()
             count += 1
         end)
 
-        CHECK(count == 2)
+        CHECK(count == 1)
 
         input(false)
 
-        CHECK(count == 4)
+        CHECK(count == 2)
     end
 
     do CASE "destruction of active scope"