ignore classes feature

src/syncback/mod.rs

@@ -385,6 +385,10 @@ pub struct SyncbackRules {
     /// syncback.
     #[serde(default, skip_serializing_if = "IndexMap::is_empty")]
     ignore_properties: IndexMap<Ustr, Vec<Ustr>>,
+    /// A list of class names to ignore entirely during syncback.
+    /// Instances of these classes will not be added, removed, or synced.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    ignore_classes: Vec<String>,
     /// Whether or not the `CurrentCamera` of `Workspace` is included in the
     /// syncback or not. Defaults to `false`.
     #[serde(skip_serializing_if = "Option::is_none")]

src/syncback/snapshot.rs

@@ -206,6 +206,24 @@ impl<'sync> SyncbackSnapshot<'sync> {
             .as_ref()
             .map(|rules| rules.ignore_trees.as_slice())
     }
+
+    /// Returns user-specified ignore classes.
+    #[inline]
+    pub fn ignore_classes(&self) -> Option<&[String]> {
+        self.data
+            .project
+            .syncback_rules
+            .as_ref()
+            .map(|rules| rules.ignore_classes.as_slice())
+    }
+
+    /// Checks if a class name should be ignored during syncback.
+    #[inline]
+    pub fn should_ignore_class(&self, class_name: &str) -> bool {
+        self.ignore_classes()
+            .map(|classes| classes.iter().any(|c| c == class_name))
+            .unwrap_or(false)
+    }
 }
 
 pub fn filter_out_property(inst: &Instance, prop_name: &str) -> bool {