[5.9] Clamp the length for WriteFile calls on win32 pipes.

ahoppen commented 10 months ago

Explanation: Cherry-picks https://github.com/apple/swift-corelibs-libdispatch/pull/796 to release/5.9, which fixes a hang of sourcekit-lsp on Windows if sourcekit-lsp tried to return a response that was >64KB (which happens if there are a lot of code completion results with comments, eg. when completing a member on String)
Scope: Only affects Windows
Risk: TBD
Testing: Will test that this fixes the sourcekit-lsp hang
Issue: https://github.com/apple/sourcekit-lsp/issues/982
Reviewer:

ahoppen commented 10 months ago

Verified that the 5.9 Windows toolchain built with this change does not have the sourcekit-lsp issue.

ahoppen commented 10 months ago

@swift-ci Please test

swiftlang / swift-corelibs-libdispatch