LLVM 19 regression: http.test.test.Server.Request.respondStreaming non-chunked, unknown content-length' failed: error: ConnectionResetByPeer

[andrewrk]

test
+- test-modules
   +- test-std
      +- run test std-aarch64-windows.win11_ge...win11_ge-gnu-cortex_a78c-ReleaseFast-libc 2681/2749 passed, 1 failed, 67 skipped
error: 'http.test.test.Server.Request.respondStreaming non-chunked, unknown content-length' failed: error: ConnectionResetByPeer
error: while executing test 'zig.system.darwin.macos.test.detect', the following test command failed:
C:\actions-runner0\_work\zig\zig\build-release\zig-local-cache\o\1b0f35d44a05135cb46764fe97a3b031\test.exe --seed=0x5d7bdeb7 --cache-dir=C:\actions-runner0\_work\zig\zig\build-release\zig-local-cache --listen=- 
test
+- test-modules
   +- test-std
      +- run test std-aarch64-windows.win11_ge...win11_ge-gnu-cortex_a78c-ReleaseFast 2680/2749 passed, 1 failed, 68 skipped
error: 'http.test.test.Server.Request.respondStreaming non-chunked, unknown content-length' failed: error: ConnectionResetByPeer
error: while executing test 'zig.system.darwin.macos.test.detect', the following test command failed:
C:\actions-runner0\_work\zig\zig\build-release\zig-local-cache\o\08b9a57a160f56f8056ad7a1e3ee182e\test.exe --seed=0x5d7bdeb7 --cache-dir=C:\actions-runner0\_work\zig\zig\build-release\zig-local-cache --listen=- 
Build Summary: 5240/5535 steps succeeded; 290 skipped; 2 failed; 55479/57842 tests passed; 2361 skipped; 2 failed
test transitive failure
+- test-modules transitive failure
   +- test-std transitive failure
      +- run test std-aarch64-windows.win11_ge...win11_ge-gnu-cortex_a78c-ReleaseFast 2680/2749 passed, 1 failed, 68 skipped
      +- run test std-aarch64-windows.win11_ge...win11_ge-gnu-cortex_a78c-ReleaseFast-libc 2681/2749 passed, 1 failed, 67 skipped
error: the following build command failed with exit code 1:
C:\actions-runner0\_work\zig\zig\build-release\zig-local-cache\o\7bd2c5c5b1b09348e171a57c59329021\build.exe C:\actions-runner0\_work\zig\zig\build-release\stage3-release\bin\zig.exe C:\actions-runner0\_work\zig\zig\lib C:\actions-runner0\_work\zig\zig C:\actions-runner0\_work\zig\zig\build-release\zig-local-cache C:\actions-runner0\_work\zig\zig\build-release\zig-global-cache --seed 0x5d7bdeb7 -Zd8a9482bec1656eb test docs --search-prefix C:\actions-runner0\_work\zig\zig\..\zig+llvm+lld+clang-aarch64-windows-gnu-0.14.0-dev.1622+2ac543388 -Dstatic-llvm -Dskip-non-native -Denable-symlinks-windows

Same failure observed on x86_64-windows (release) and aarch64-windows.

[truemedian]

I have now encountered this bug on the master branch on zig on all platforms, it seems to be a miscompilation. When write_cl has enough data to commit a full write to the socket, it works fine and r.send_buffer_end is reset to zero as expected. However (likely because of the constcast?) response for some reason does not reflect this modification.

This causes r.send_buffer_end to be fixed at 490, and as such each subsequent line write causes a full ~500 byte message to be sent. This is way more than the 8192 limit provided by the client in readAllAlloc; the client then errors with StreamTooLong and closes the connection; The server then tries to write to a closed socket and recieves ConnectionResetByPeer