pre-commit hook doesn't work when using #!/bin/bash on windows

Description

Basically if a pre-commit hook uses #!/bin/bash rather than #!/bin/sh then it works on the command line (in all of cmd, git bash and powershell) but causes this error in the github app:

Commit failed - exit code 1 received, with output: 'error: cannot spawn
C:/Users/Public/github-desktop-issue/githooks/pre-commit: No such file or directory'

Version

• GitHub Desktop: 1.4.0
• Operating system: Microsoft Windows [Version 10.0.17134.285]

Steps to Reproduce

1. Clone this repository: https://bitbucket.org/Jamesernator/github-desktop-issue
2. Change the githooks directory using git config core.gitHooks githooks while in the repo directory
3. Change the example file somehow
4. Try to commit in Github Desktop
5. Error occurs because of #!/bin/bash
6. EXTRA: Try committing in a regular shell, this works per normal

Expected Behavior

I expected the git hook to work like it did in all three regular shells.

Actual Behavior

The error mentioned in the top of the post occurs.

Additional Information

Logs

2018-09-12.desktop.production.log

Non-Solutions Tried:

Although #!/bin/sh works on windows (as it uses bash) it’s a non-solution for user’s on other operating systems as #!/bin/sh does not in general point to #!/bin/bash.

Creating a trivial #!/bin/sh file that uses bash ./pre-commit.bash doesn’t work Windows as bash isn’t found when run in the github app pre-commit hook.

[Kurt-von-Laven]

@maystar, add %LOCALAPPDATA%\Programs\Git\bin to your user’s path via Settings (Win + I) > Edit environment variables for your account > User variables for … > Path > Edit…. %LOCALAPPDATA% expands to C:\Users\<user>\AppData\Local\.

[shiftkey]

This script worked for me on Windows 10 without a Git for Windows installation on the path:

#!/bin/sh
if [ "$(expr match $(uname -s) 'MINGW64_NT*')" == "10" ]; then
  echo "You may commit on Windows"
  exit 2
else
  echo "You cannot commit on this non-Windows OS"
  exit 3
fi

Setting .git/hooks/precommit to this script and making a commit would error (as intended) but with the expected message:

I think uname -s is a fine enough approach here, but maybe older versions of Windows report the numbers differently: