Redundant output when running stack with previously installed msys2

[asampal]

I had msys2/mingw already installed on my Windows system and ran stack --skip-msys setup to install GHC without another copy of msys2 being installed.

Now, when I run a stack command, say stack ghci, I get the following line as part of the output of that command: Continuing despite missing tool: msys2. If I run stack --skip-msys ghci that line is not output.

This is wrong, with or without the --skip-msys option, given that I do have msys2 installed. Where is stack looking to make it think that it's missing? Building a newly created project works, btw.

[mgsloan]

That output comes from here. It thinks that it isn't installed because it isn't in the list of installed programs.

I suppose we ought to do something similar to what we do for GHC - it finds the ghc executable and asks for its version.

[asampal]

When you say 'list of installed programs', what are these? It wasn't clear to me, looking at the source where you pointed. Is it a subset of the tools that come with msys2/mingw? Is msys2 expected to be in a specific place on the filesystem?

[mgsloan]

It's looking in the spot that it's installing programs. On windows, IIRC, this is in some sort of app data folder within your user folder. One nice thing about this is that we can rely on the directory including the version of the program installed.

This isn't that big of a deal with msys, though, I don't think we control msys versions. So maybe it would be sufficient to just check if some particular msys stuff is on the PATH, and consider the tool installed in that case.

[asampal]

I'd say that your last suggestion is what would make the most sense. Figure out the subset of tools to check for on the path, along with their versions, and you should be OK. Also, for the MinGW tools, which would usually be installed along with MSYS2, MINGW_HOME would typically be set.

[mgsloan]

Yup, feel free to make the necessary changes and open a PR!

[asampal]

That will have to wait since I'm a total noob at Haskell.

[mgsloan]

Gotcha, no worries :)