Tests randomly fail with "Exception: fd:111: hPutBuf: resource vanished (Broken pipe)" (--test-option=-j1 workaround)

[anka-213]

When running the func-test test-suite locally, some of the tests randomly fail with the error:

Exception: fd:111: hPutBuf: resource vanished (Broken pipe)

This issue is a subset of issue #1430, but not on CI.

Your environment

Output of haskell-language-server --probe-tools or haskell-language-server-wrapper --probe-tools:

haskell-language-server version: 1.1.0.1 (GHC: 9.0.1) (PATH: /Users/anka/projekt/not-mine/haskell/haskell-language-server/dist-newstyle/build/x86_64-osx/ghc-9.0.1/haskell-language-server-1.1.0.1/x/haskell-language-server/build/haskell-language-server/haskell-language-server) (GIT hash: 8e03c8d08a51a69024c154bf93408a4595b45f8c)
Tool versions found on the $PATH
cabal:          3.4.0.0
stack:          2.7.1
ghc:            9.0.1

Which OS do you use: MacOS

Steps to reproduce

I can't reliably reproduce it, but every few times when I run

cabal test func-test

some of the tests fail with the error above.

Actual behaviour

  plugin config
    hlint plugin enables
      changing hlintOn configuration enables or disables hlint diagnostics:                    OK (2.51s)
      changing hlint plugin configuration enables or disables hlint diagnostics:               OK (2.43s)
      adding hlint flags to plugin configuration removes hlint diagnostics:                    OK (2.95s)
      adding hlint flags to plugin configuration adds hlint diagnostics:                       FAIL
        Exception: fd:111: hPutBuf: resource vanished (Broken pipe)
    config parsing

More examples (this time ghc-8.10.4):

``` haskell-language-server commands are prefixed: OK (3.07s) get de-prefixed: OK (3.06s) completions works: FAIL Exception: fd:97: hPutBuf: resource vanished (Broken pipe) itemCompletion/resolve works: IGNORED no support for itemCompletion/resolve requests completes imports: OK (5.17s) completes qualified imports: FAIL Exception: fd:135: hPutBuf: resource vanished (Broken pipe) completes with no prefix: FAIL Exception: fd:129: hPutBuf: resource vanished (Broken pipe) strips compiler generated stuff from completions: OK (4.75s) have implicit foralls on basic polymorphic types: OK (4.99s) have implicit foralls with multiple type variables: OK (4.93s) maxCompletions: FAIL Exception: fd:99: hPutBuf: resource vanished (Broken pipe) contexts only provides type suggestions: FAIL Exception: fd:126: hPutBuf: resource vanished (Broken pipe) only provides value suggestions: FAIL Exception: fd:132: hPutBuf: resource vanished (Broken pipe) completes qualified type suggestions: FAIL Exception: fd:137: hPutBuf: resource vanished (Broken pipe) snippets work for argumentless constructors: OK (4.85s) work for polymorphic types: FAIL Exception: fd:123: hPutBuf: resource vanished (Broken pipe) work for complex types: OK (5.05s) work for infix functions: OK (2.30s) work for infix functions in backticks: OK (2.36s) work for qualified infix functions: OK (2.41s) work for qualified infix functions in backticks: OK (2.48s) respects lsp configuration: OK (2.69s) respects client capabilities: OK (2.65s) plugin config hlint plugin enables changing hlintOn configuration enables or disables hlint diagnostics: FAIL Exception: fd:129: hPutBuf: resource vanished (Broken pipe) changing hlint plugin configuration enables or disables hlint diagnostics: FAIL Exception: fd:97: hPutBuf: resource vanished (Broken pipe) adding hlint flags to plugin configuration removes hlint diagnostics: FAIL Exception: fd:100: hPutBuf: resource vanished (Broken pipe) adding hlint flags to plugin configuration adds hlint diagnostics: OK (5.05s) config parsing empty object as user configuration should not send error logMessage: OK (0.66s) ```

Include debug information

Output from:

LSP_TEST_LOG_MESSAGES=1 LSP_TEST_LOG_STDERR=1 cabal test func-test 

It's 69000 lines, so I put it in a gist: https://gist.github.com/e12414f103af1c13768cd2735b608acb Not sure how to reduce it, since the issue disappears when you only run a single test at a time. Here's a shorter one ("only" 1500 lines) with only three tests running: https://gist.github.com/d51856f6ff15b69434bf1f1a4b8ddb6e

[berberman]

Could you try running them in -j1?

[anka-213]

@berberman Do you mean changing this line? https://github.com/haskell/haskell-language-server/blob/959da6207406ee17b56051e386ff9d2c1e511c23/test/utils/Test/Hls/Command.hs#L26 Or adding --test-option=-j1 to the cabal command?

[berberman]

Use --test-option=-j1. The -j4 in the code means threads used by ghcide, but here we want to run test cases sequentially.

[anka-213]

The --test-option=-j1 does make the symptoms disappear, as expected.

[anka-213]

I did however manage to reproduce the error previously while running only a single test, while Haskell Language Server was compiling a bunch of packages in the background, so maybe the system load matters (which would make sense for a race-condition).

[michaelpj]

Closing since I haven't seen any complaints about that recently

[soulomoon]

Still seeing them if the work load is high.

[soulomoon]

Potentially the same problem? https://github.com/unisonweb/unison/pull/3783