Feature request: opt-in setting to clear diagnostics immediately on didChange

[alliprice]

Is your feature request related to a problem? Please describe.

When pyright is used as a language server by AI coding tools, stale diagnostics cause problems. The tool edits a file via textDocument/didChange, then reads diagnostics to decide what to do next. Because reanalysis is async, the diagnostics it reads are from the previous state. This causes the tool to re-fix already-fixed errors, miss newly introduced errors, or loop on diagnostics that no longer apply.

This isn't a problem for interactive editors where a human is still typing and the debounce is desirable.

Describe the solution you'd like

An opt-in setting (pyright.eagerDiagnosticInvalidation, default false) that publishes empty diagnostics for a file immediately on didChange, before reanalysis completes. No behavior change for anyone who doesn't enable it.

The setting would be configured by tool vendors in their LSP initialization config, not by end users.

I have a working implementation with tests if there's interest.

[erictraut]

We've had requests over the years to make the debounce value user-definable. Rather than making this a boolean, maybe it would make more sense to make it a numeric value.

[alliprice]

I think that makes sense to accommodate a larger population of users. I would be open to changing the implementation.