LSP is never started for initial unsaved buffer

[jwortmann]

A small inconvenience that I noticed when you open a fresh instance of Sublime Text and start to type in the initial buffer.
I'm not sure why exactly it happens, maybe it's some timing issue or even a ST bug could be the cause?

To Reproduce

With a language server configured to be active for unsaved buffers, e.g. LSP-pyright with default config "schemes": ["file", "buffer", "res"] ...

Case A:

1. Start ST
2. Run Set Syntax: Python from the command palette
3. Type print('hello')

Case B:

1. Start ST
2. Type print('hello')
3. Run Set Syntax: Python from the command palette

Case C:

1. Start ST
2. Ctrl+N (invokes new_file command)
3. Run Set Syntax: Python from the command palette
4. Type print('hello')

Expected behavior
Case A: no LSP (ideally only until you select another tab and then the first tab again)¹
Case B: LSP started
Case C: LSP started

Actual behavior
Case A: no LSP (even after you select another tab and then the first tab again!)
Case B: no LSP
Case C: LSP started

Environment (please complete the following information):

• OS: Windows 11
• Sublime Text version: 4152
• LSP version: 663afdc (latest commit at the time of writing this)

Additional context
With debug logging enabled, LSP: couldn't find a text change listener for ViewListener(12) gets printed to the console (twice). But if you add a print statement for debugging into the TextChangeListener.attach method from the plugin/core/documents.py file, you can see that this method does get called even for the initial buffer 🤷

Footnotes

1. This expectation is with the limitations of the current implementation in mind, i.e. check in DocumentSyncListener.on_activated_async whether to start a language server ↩