Don't assume DidChangeTextDocument paths exist

[madelynnblue]

Fixes #5933

[madelynnblue]

My (probably buggy?) acme client causes rust-anayzer to crash a few times per day on this. While clients should do a good job, it is currently trivial to panic rust-analyzer if you send it a ChangeText notification on some random path.

[SomeoneToIgnore]

Thank you!

bors r+

[bors]

Build succeeded:

• TypeScript (windows-latest)
• Rust (macos-latest)
• Rust (ubuntu-latest)
• Rust (windows-latest)
• TypeScript (ubuntu-latest)

[kjeremy]

Is this correct behavior? Why doesn't the path exist? The client needs to gain ownership of the fire first by sending DidOpen which should have a valid URI.

[madelynnblue]

I agree the client should do that. I thought I programmed mine to always send an open first, but apparently it has a bug. However, it should never just panic rust-analyzer.

[matklad]

However, it should never just panic rust-analyzer.

For some historical context, we used to deliberately panic in such cases (to force the us/clients fix all the bugs), but we've changed our stance on this.

That said, I think we need to abstract this away into some kind of log_protocol_violation error, such that we can show an error message to the client or something like that. But that, to be done nicely, requires re-engineering of our event loop I think....