Fix script overwriting with external editor

[kitbdev]

• fixes Godots script editor overwrites code from external editor when saving (VS Code) #88399
• fixes Code in VSCode deletes recent saved changes when connecting signal from Editor #91314
• fixes Exported Variables disappearing in editor upon launching a scene #82266
• alternative to Prevent saving scripts if using external editors. #95969
• related Fixes internal Script Editor crash with External Editor active #82956
• related Crash while editing GDScript in VS Code via LSP #71016

#82956 does not fix the crash in #71016 if the external editor setting is turned off.
Basically this undoes #82956 and has an alternate fix for #71016.

#71016 happens because ScriptEditor::_reload_scripts it is called from a thread, and it is not safe to do so.
ERR_MAIN_THREAD_GUARD won't work here since GDScriptLanguageServer::thread_main sets set_current_thread_safe_for_nodes to true, even though its not really thread safe.

For instance, the crash is potentially caused by GDScriptSyntaxHighlighter::_get_line_syntax_highlighting_impl being called from TextEdit's draw in the main thread, while ScriptEditor::reload_scripts calls ScriptTextEditor::reload_text(), ScriptTextEditor::_validate_script(), then GDScriptSyntaxHighlighter::_update_cache, which changes things while it is trying to be drawn.

[radiantgurl]

Will this reload also solve resource desyncs between the external editor and internal one?

[kitbdev]

Will this reload also solve resource desyncs between the external editor and internal one?

This should only affect script resources, they will be synced. Other resources should behave the same. Is there an issue for non-script resource desyncs?

[radiantgurl]

Will this reload also solve resource desyncs between the external editor and internal one?

This should only affect script resources, they will be synced. Other resources should behave the same. Is there an issue for non-script resource desyncs?

No, i was just talking about script desyncs. Thank you for fixing it!

[petzki]

This should fix #94080.

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 4.3.1.

[BlackDragonBE]

Does this fix #82266 as well?

[akien-mga]

Does this fix #82266 as well?

Since you've been looking into it, the easiest way to confirm would be for you to test https://godotengine.org/article/dev-snapshot-godot-4-4-dev-2/ which includes this fix.

[BlackDragonBE]

@akien-mga I just tested the steps to reproduce the bug with 4.4-dev2 and I can confirm that it's fixed. #82266 can be closed as well.