"resource busy (file is locked)" failures running tests locally

[philderbeast]

Describe the bug
I'm seeing "resource busy (file is locked)" failures running tests locally.

To Reproduce

$ cabal test cabal-install:unit-tests
 UnitTests.Distribution.Client.UserConfig
    nullDiffOnCreate:                                                                                                                  FAIL
      Exception: ghc-internal:GHC.Internal.IO.Exception.IOException:
      
      /home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config.tmp: withFile: resource busy (file is locked)
      
      HasCallStack backtrace:
        ioException, called at libraries/ghc-internal/src/GHC/Internal/IO/FD.hs:331:17 in ghc-internal:GHC.Internal.IO.FD
      
      Use -p '/nullDiffOnCreate/' to rerun this test only.
    canDetectDifference:                                                                                                               OK
    canUpdateConfig:                                                                                                                   FAIL
      Exception: ghc-internal:GHC.Internal.Exception.ErrorCall:
      
      fromFlag NoFlag. Use fromFlagOrDefault
      
      HasCallStack backtrace:
        error, called at src/Distribution/Simple/Flag.hs:83:19 in Cabal-3.17.0.0-inplace:Distribution.Simple.Flag
        fromFlag, called at tests/UnitTests/Distribution/Client/UserConfig.hs:63:5 in cabal-install-3.17.0.0-inplace-unit-tests:UnitTests.Distribution.Client.UserConfig
      
      Use -p '/canUpdateConfig/' to rerun this test only.
    doubleUpdateConfig:                                                                                                                FAIL
      Exception: ghc-internal:GHC.Internal.IO.Exception.IOException:
      
      /home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config.tmp: withFile: resource busy (file is locked)
      
      HasCallStack backtrace:
        ioException, called at libraries/ghc-internal/src/GHC/Internal/IO/FD.hs:331:17 in ghc-internal:GHC.Internal.IO.FD
      
      Use -p '/doubleUpdateConfig/' to rerun this test only.
    newDefaultConfig:
...

It is not always 3 tests that fail. Here's another run:

 UnitTests.Distribution.Client.UserConfig
    nullDiffOnCreate:                                                                                                                  FAIL
      Exception: ghc-internal:GHC.Internal.IO.Exception.IOException:
      
      /home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config: withBinaryFile: resource busy (file is locked)
      
      While handling /home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config: withBinaryFile: resource busy (file is locked)
      
      HasCallStack backtrace:
        ioError, called at src/Distribution/Client/Config.hs:1065:14 in cabal-install-3.17.0.0-inplace:Distribution.Client.Config
      
      Use -p '/nullDiffOnCreate/' to rerun this test only.
    canDetectDifference:                                                                                                               FAIL
      Exception: ghc-internal:GHC.Internal.IO.Exception.IOException:
      
      /home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config.tmp: withFile: resource busy (file is locked)
      
      HasCallStack backtrace:
        ioException, called at libraries/ghc-internal/src/GHC/Internal/IO/FD.hs:331:17 in ghc-internal:GHC.Internal.IO.FD
      
      Use -p '/canDetectDifference/' to rerun this test only.
    canUpdateConfig:                                                                                                                   FAIL
      Exception: ghc-internal:GHC.Internal.IO.Exception.IOException:
      
      renameFile:renamePath:rename '/home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config.tmp' to '/home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config': does not exist (No such file or directory)
      
      While handling renamePath:rename '/home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config.tmp' to '/home/.../cabal/cabal-install/tests/fixtures/project-root/test-user-config': does not exist (No such file or directory)
      
      Use -p '/canUpdateConfig/' to rerun this test only.

Expected behavior
That these tests pass when run locally.

System information

• cabal-3.16.1.0
• ghc-9.14.1

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 25.10
Release:	25.10
Codename:	questing

I tested with master at cc98704 and as far back as 9a32847 and still see failures.

[geekosaur]

That's a bit odd, since I often validate locally before pushing and don't see these.

[Bodigrim]

That's perhaps another consequence of tasty-1.5.4 running tests concurrently. All tests in the module use the same temporary file, as created in bracketTest. This is wrong, bracketTest should employ System.IO.openTempFile to generate unique files.

[ulysses4ever]

#11759 is meant to fix it