fix: use update_file() instead of full scan() on single-file writes (#508)

script_create, script_patch, and filesystem write_text each triggered a full
recursive EditorInterface.get_resource_filesystem().scan() per write. Under
concurrent file creation (e.g. multiple MCP clients, or a stress run) these
scans stack: the editor re-enqueues the update_scripts_classes /
update_script_paths_documentation WorkerThreadPool tasks while a previous scan
is still pending, emitting "Task '...' already exists" / Condition
"!tasks.has(p_task)" is true, and the global-class registry is left
inconsistent. The next idle filesystem scan can then SIGABRT in
ScriptServer::remove_global_class_by_path() — a hard editor crash.

Switch all three sites to EditorFileSystem.update_file(path), the single-file
registration call the rest of the plugin already uses (material/theme handlers,
filesystem reimport, resource_io). It registers just the written file without
the recursive scan-action batch, so the duplicate-task race can't occur.

Validated with a concurrency stress harness:
- before (full scan): 5x "Task ... already exists" + 5x "!tasks.has(p_task)"
  per run, intermittently escalating to the SIGABRT (3 crash reports).
- after (update_file): 0 of those engine errors across heavier runs, no crash.
- create -> immediate attach still settles (import_settled=true), so the #261
  import-settle behaviour is preserved.
- GDScript script (38) + filesystem (16) suites pass; Python import-settle (6)
  + script/filesystem unit tests (67) pass.

Engine-side record of the underlying abort: dsarno/godot#6.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: dsarno

plugin/addons/godot_ai/handlers/filesystem_handler.gd

@@ -57,8 +57,13 @@ func write_file(params: Dictionary) -> Dictionary:
 	file.store_string(content)
 	file.close()
 
-	# Trigger reimport so the editor recognises the new/changed file
-	EditorInterface.get_resource_filesystem().scan()
+	# Single-file register, not a full scan() — a scan() per write stacks
+	# filesystem WorkerThreadPool tasks under concurrent writes and can SIGABRT
+	# in the global-class update (see dsarno/godot#6 and create_script in
+	# script_handler.gd). update_file() is what reimport()/material/theme use.
+	var efs := EditorInterface.get_resource_filesystem()
+	if efs != null:
+		efs.update_file(path)
 
 	var data := {
 		"path": path,

plugin/addons/godot_ai/handlers/script_handler.gd

@@ -50,8 +50,16 @@ func create_script(params: Dictionary) -> Dictionary:
 	file.store_string(content)
 	file.close()
 
-	# Trigger reimport so the editor recognises the new file
-	EditorInterface.get_resource_filesystem().scan()
+	# Register just this file with the editor instead of a full recursive
+	# scan(). A scan() per write stacks `update_scripts_classes` /
+	# `update_script_paths_documentation` WorkerThreadPool tasks under concurrent
+	# script creation ("Task ... already exists" / "!tasks.has(p_task)"), which
+	# races the global-class registry and can SIGABRT in
+	# ScriptServer::remove_global_class_by_path (see dsarno/godot#6).
+	# update_file() is the single-file path the rest of the plugin already uses.
+	var efs := EditorInterface.get_resource_filesystem()
+	if efs != null:
+		efs.update_file(path)
 
 	var data := {
 		"path": path,
@@ -206,7 +214,10 @@ func patch_script(params: Dictionary) -> Dictionary:
 	write.store_string(new_content)
 	write.close()
 
-	EditorInterface.get_resource_filesystem().scan()
+	# Single-file register, not a full scan() — see create_script (dsarno/godot#6).
+	var efs := EditorInterface.get_resource_filesystem()
+	if efs != null:
+		efs.update_file(path)
 
 	return {
 		"data": {