Fix LSP crash parsing scripts with no lines [3.x]

[Razoric480]

Certain LSP clients like Vim occasionally, erroneously, or for whatever reason report documents as being size 0, which breaks the LSP due to a fix in parsing documentation that is above multi-line functions parameters.

Fixes #53238

[Rubonnek]

Nice! No crashes! But I've stumbled into a minor issue.

When I save, now I'm getting the following message: Unexpected token: Identifier:Null

Here's the LSP interaction: unexpected_token_identifier_null.txt.

You'll find the unexpected token message at the bottom of that log.

[Razoric480]

That looks like a client issue. It's reporting that your script became:

Null

which even in Godot itself would trigger Unexpected Token: Identifier: Null

Could the LSP client code in Vim be reporting some temporary file it's using for saving a file, instead of the saved file end result?

[Rubonnek]

That's quite possible. As far as I can tell, this seems to be a bug within ALE which might be referencing some temporary file.

I'll look into it.

[Razoric480]

For now, this will at least keep the LSP itself from dying and keep Godot from crashing, so it's good for merging

[akien-mga]

Thanks!

[Rubonnek]

Welp, I've confirmed that the Unexpected token: Identifier:Null issue is indeed a bug in ALE.

The textDocument/didSave message is not including the contents of the file at all, which it should according to the official LSP specification. I'll submit a PR to ALE sometime this week.

@Razoric480 thanks for the quick turnaround on this!

[Razoric480]

♥ Glad it worked out

[akien-mga]

Cherry-picked for 3.3.4.