stack fails on Windows with git package in stack.yaml and no git binary on path

[conklech]

On a Windows system with no git on the system/user %PATH% and a git repository package in stack.yaml, stack (sometimes?) completely fails within the project folder.

$ cat stack.yaml
[...]
- location:
    git: https://github.com/conklech/threepenny-gui.git
    commit: b426b55bc34704b66da35b256c3e7505b044b636
$ stack build
Executable named git not found on path: ["C:\\ProgramData\\Oracle\\Java\\javapath","C:\\Windows\\system32","C:\\Windows","C:\\Windows\\System32\\Wbem","C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\","C:\\Program Files (x86)\\NVIDIA Corporation\\PhysX\\Common","%SystemRoot%\\system32","%SystemRoot%","%SystemRoot%\\System32\\Wbem","%SYSTEMROOT%\\System32\\WindowsPowerShell\\v1.0\\","C:\\Users\\chris\\AppData\\Roaming\\local\\bin"]
$ stack exec -- echo "nothing"
Executable named git not found on path: ["C:\\ProgramData\\Oracle\\Java\\javapath","C:\\Windows\\system32","C:\\Windows","C:\\Windows\\System32\\Wbem","C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\","C:\\Program Files (x86)\\NVIDIA Corporation\\PhysX\\Common","%SystemRoot%\\system32","%SystemRoot%","%SystemRoot%\\System32\\Wbem","%SYSTEMROOT%\\System32\\WindowsPowerShell\\v1.0\\","C:\\Users\\chris\\AppData\\Roaming\\local\\bin"]
$ cd ..
$ stack exec -- where git
Run from outside a project, using implicit global config
Using resolver: lts-2.20 from global config file: C:\Users\chris\AppData\Roaming\stack\global\stack.yaml
C:\Users\chris\AppData\Local\Programs\stack\i386-windows\git-2.4.5.1\cmd\git.exe

This condition is fragile. After adding git.exe to the %PATH% and running stack build (which succeeds), and then opening a new shell with the original %PATH%, stack functions normally again, even after stack clean. I don't know what the exact preconditions for the buggy behavior are.

[snoyberg]

Are you using a system-installed GHC in this case?

What is the resolution you're proposing here? Obviously git is necessary in order to execute the build plan.

[conklech]

No, there is no system-installed ghc or git.

The stack copy of git is available (see last line of log) and can be run via stack exec, but stack isn't looking in %LOCALAPPDATA%\Programs\stack\...\git-*\cmd\ when it tries to run git within the project directory (it's not in the list of folders following "Executable named git not found on path:"). I could have made the report clearer on that point; sorry.

The requested resolution is for stack to use the git installed via stack setup in all cases when there is no system git. Its folder should be added to (the end of?) the search path.

[snoyberg]

Thanks, that clarifies. I've just pushed a commit to the 712-clone-modified-env branch that should resolve this. Can you give it a try and, if it works correctly for you, I'll merge to master and close out this issue.

[conklech]

Works perfectly. Thanks!

[snoyberg]

Cool, merged to master.