Closed Bug 1229154 Opened 7 years ago Closed 7 years ago

`mach eslint` fails on Windows with WindowsError: Error 193 %1 is not a valid Win32 application


(Firefox Build System :: Mach Core, enhancement)

Not set


(firefox45 fixed)

Tracking Status
firefox45 --- fixed


(Reporter: jaws, Assigned: jaws)



(1 file)

jared@jaws-win8 /c/fx
$ mach eslint browser/base/content/
 0:00.92 Running c:\Users\jared\AppData\Roaming\npm\eslint in browser/base/content/
 0:00.92 c:\Users\jared\AppData\Roaming\npm\eslint --ext [.js,.jsm,.jsx] browser/base/content/
Error running mach:

    ['eslint', 'browser/base/content/']

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.

You should consider filing a bug for this issue.

If filing a bug, please include the full output of mach, including this error

The details of the failure are as follows:

WindowsError: [Error 193] %1 is not a valid Win32 application

  File "c:\fx\python/", line 220, in eslint
    ensure_exit_code=False,  # Don't throw on non-zero exit code.
  File "c:\fx\python/mach\mach\mixin\", line 121, in run_process
    proc = subprocess.Popen(args, cwd=cwd, env=use_env)
  File "c:\mozilla-build\python\lib\", line 710, in __init__
    errread, errwrite)
  File "c:\mozilla-build\python\lib\", line 958, in _execute_child
On both Windows and UNIX, you can execute a binary executable and it works. That's normal.

On UNIXen, if an executable file isn't an ELF/binary, the first line of the file is examined for the shebang (#!<binary>). If that's present, the executable referenced is run and the file is passed to it.

Windows doesn't have exactly this behavior. So, if you try to launch a process from a file with a shebang, you get the "is not a valid Win32 application" error. If you are inside a msys shell, the shell itself looks for the shebang and you are good. But Python processes aren't spawned directly from the shell: they are spawned from Python using the Win32 APIs directly. So to execute a process via the Python APIs, it needs to be a true Win32 executable or it needs to be spawned through a shell.

If you pass require_unix_environment=True to mach's run_process() helper function, it will spawn processes in an appropriate shell and the shebang detection should work. Otherwise, the argument passed must be a Win32 executable on Windows.
Wow, very insightful. Thanks for the details, I'll put a patch up here shortly.
Assignee: nobody → jaws
Attached patch PatchSplinter Review
Tested this change and it now works through mach on Windows. Thanks!
Attachment #8694327 - Flags: review?(gps)
Attachment #8694327 - Flags: review?(gps) → review+
Bug 1229154 - Launch 'eslint' with UNIX environment since 'eslint' is not a valid Win32 binary. r=gps
Closed: 7 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla45
Product: Core → Firefox Build System
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