fix(lsp): SourceKit does not activate for Objective-C (.m) and Objective-C++ (.mm) files

[amirlankalm]

Description

The SourceKit language server in src/lsp/server.ts has incorrect file extensions:

extensions: [".swift", ".objc", "objcpp"],

Two bugs:

1. ".objc" is the VSCode language ID for Objective-C, not a file extension. Objective-C files use .m.
2. "objcpp" is the language ID for Objective-C++ and is also missing the leading dot. Objective-C++ files use .mm.

The LSP dispatcher at src/lsp/lsp.ts:261 matches via path.parse(file).ext, which returns ".m" and ".mm" respectively. Neither matches the current extension list, so SourceKit never activates for any Objective-C or Objective-C++ file.

Expected behavior

SourceKit should activate for .m (Objective-C) and .mm (Objective-C++) files in addition to .swift.

Fix

extensions: [".swift", ".m", ".mm"],

This matches the mappings already present in src/lsp/language.ts:

".m": "objective-c",
".mm": "objective-cpp",

[github-actions]

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This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: Add built-in LSP support for Objective-C (.m, .mm, .h) #19092: Describes the exact same problem — SourceKit not activating for .m and .mm Objective-C files, with the same fix proposed.
• Add sourcekit-lsp as built-in for Swift and Objective-C #1544 (closed): Original request to add sourcekit-lsp as a built-in for Swift and Objective-C.

If you believe this was flagged incorrectly, please let a maintainer know.

[amirlankalm]

Closing — this is a duplicate of #19092 which tracks the same problem. PR #29315 fixes it and references #19092 directly.