Need to handle diagnostics without file field

[tomv564]

The language service is failing to return diagnostics and logging errors when compiler diagnostics are returned alongside file diagnostics.

These diagnostics (despite the typing of ts.Diagnostic) have no file field (typically just a code and a message).

To avoid exceptions handling those diagnostics, adding a tsDiagnostics.filter(f => !!f.file) is needed before calling convertTsDiagnostic in _publishDiagnostics

[felixfbecker]

Could you report that as a bug to TypeScript as well? The interface doesn't mention that file is optional

[tomv564]

Technically, the field is specified :)
https://github.com/Microsoft/TypeScript/blob/2150a7796b0dfe83c5286755410e0fd1646ed86c/src/compiler/core.ts#L1235-L1251

[felixfbecker]

The declared type of the property is SourceFile, not SourceFile | undefined. TS' type system doesn't differentiate between present properties and undefined properties, if they had enabled strictNullChecks the code you linked would cause a compile error.

[felixfbecker]

Filed microsoft/TypeScript#15666

[tomv564]

Ah, just as I threw microsoft/TypeScript#15667 on the pile.

[tomv564]

I closed mine. Surprised they are not running with strictNullChecks already - my expectation was to find an as Diagnostic somewhere :)

[felixfbecker]

Yes, I am receiving so many cannot read x of undefined errors from within the TS codebase that could probably be all solved with that flag.