[Siddharth S (codeXsidd)]

Summary

Ensures TextDocumentFilter.is, TextDocumentRegistrationOptions.is, WorkDoneProgressOptions.hasWorkDoneProgress, and DiagnosticServerCancellationData.is safely handle null and undefined without throwing TypeError and return boolean results.

Problem

TextDocumentFilter.is did not verify whether a non-string candidate is an object literal before reading candidate properties (candidate.language). Passing null or undefined threw TypeError: Cannot read properties of null (reading 'language') instead of returning false.

Consequently, composite guards like DocumentSelector.is([null]) and TextDocumentRegistrationOptions.is({ documentSelector: [null] }) crashed with a TypeError. In addition, TextDocumentRegistrationOptions.is(null), WorkDoneProgressOptions.hasWorkDoneProgress(null), and DiagnosticServerCancellationData.is(null) returned null rather than boolean false.

Solution

• Added Is.objectLiteral(candidate) checks in TextDocumentFilter.is, TextDocumentRegistrationOptions.is, WorkDoneProgressOptions.hasWorkDoneProgress, and DiagnosticServerCancellationData.is.
• Added unit tests in protocol/src/node/test/documentFilter.test.ts covering TextDocumentFilter.is, DocumentSelector.is, TextDocumentRegistrationOptions.is, WorkDoneProgressOptions.hasWorkDoneProgress, and DiagnosticServerCancellationData.is for valid filters, relative patterns, invalid values, and null / undefined.

Testing

• npm run compile:protocol: passed cleanly
• npm run compile (full project build mode across all packages): passed cleanly
• npm --prefix protocol run lint: passed cleanly (0 errors)
• npm --prefix protocol run test:node: passed (all 26 tests passing)
• npm --prefix types test: passed (all 58 tests passing)
• npm --prefix server test: passed (all 17 tests passing)

Related Issue

Closes #1939

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota. Try requesting a review at a lower effort level.

[Siddharth S (codeXsidd)]

@microsoft-github-policy-service agree

[Copilot]

🟢 Approval recommended

No active review issues are recorded for the null-safe protocol type-guard changes.

No open issues 🎉

_{Review effort: Balanced}

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota. Try requesting a review at a lower effort level.

[Copilot]

🟢 Approval recommended

No active review issues are identified for the null-safe protocol type guard changes.

No open issues 🎉

_{Review effort: Balanced}