opam init with MSYS2

[jonahbeckford]

          I am quite fine with `OPAMFETCH=wget` ... it is only for the initial `opam init`.

And it gets past the curl issue, so technically this issue can be closed.

However, opam init fails at a later point, and I do now think that --msys2-location=DIR is unavoidable. I'll open a new issue for that.

Originally posted by @jonahbeckford in #5681 (comment)

[jonahbeckford]

Problem

Using opam init --no-cygwin-setup:

$env:OPAMFETCH="wget"; with-dkml opam init --yes --no-setup --bare --disable-sandboxing --no-cygwin-setup --verbose --debug-level 4 default https://opam.ocaml.org

gives:

<><> Fetching repository information ><><><><><><><><><><><><><><><><><><><>  🐫
00:00.092  PARALLEL               Iterate over 1 task(s) with 3 process(es)
00:00.092  PARALLEL               Starting job 0 (worker 1/3): 0
00:00.093  REPOSITORY             update default from https://opam.ocaml.org
00:00.093  CURL                   pull-repo-update
00:00.094  SYSTEM                 mkdir Z:\Temp\opamroot1\repo\default.new
00:00.095  SYSTEM                 mkdir C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62
00:00.097  SYSTEM                 mkdir C:\Users\beckf\AppData\Local\Temp\opam-beckf-29332
00:00.100  PARALLEL               Next task in job 0: C:\Users\beckf\AppData\Local\Programs\DKMLNA~1\tools\MSYS2\usr\bin\wget.exe --content-disposition -t 3 -O C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62\index.tar.gz.part -U opam/2.2.0~alpha3~dev -- https://opam.ocaml.org/index.tar.gz
Processing  1/1: [default: http]
00:02.795  PARALLEL               Collected task for job 0 (ret:0)
00:02.795  SYSTEM                 mv C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62\index.tar.gz.part -> C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62\index.tar.gz
00:02.804  PARALLEL               Next task in job 0: C:\Users\beckf\AppData\Local\Programs\DKMLNA~1\tools\MSYS2\usr\bin\tar.exe xfz C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62\index.tar.gz -C Z:\Temp\opamroot1\repo\default.new
00:05.680  PARALLEL               Collected task for job 0 (ret:2)
00:05.684  SYSTEM                 rmdir C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62
00:05.685  SYSTEM                 rm C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62\index.tar.gz
00:05.687  SYSTEM                 rmdir Z:\Temp\opamroot1\repo\default.new
[ERROR] Could not update repository "default": Failed to extract archive C:\Users\beckf\AppData\Local\Temp\opam-29332-a1ba62\index.tar.gz:
        "C:\\Users\\beckf\\AppData\\Local\\Programs\\DKMLNA~1\\tools\\MSYS2\\usr\\bin\\tar.exe xfz C:\\Users\\beckf\\AppData\\Local\\Temp\\opam-29332-a1ba62\\index.tar.gz -C
        Z:\\Temp\\opamroot1\\repo\\default.new" exited with code 2
00:05.688  PARALLEL               Job 0 finished
00:05.689  SYSTEM                 rmdir Z:\Temp\opamroot1
00:05.691  SYSTEM                 rm Z:\Temp\opamroot1\repo\state-265DFA6D.cache
00:05.692  SYSTEM                 rm Z:\Temp\opamroot1\repo\repos-config
00:05.693  SYSTEM                 rm Z:\Temp\opamroot1\repo\lock
00:05.694  SYSTEM                 rm Z:\Temp\opamroot1\lock
00:05.696  SYSTEM                 rm Z:\Temp\opamroot1\config.lock
00:05.697  SYSTEM                 rm Z:\Temp\opamroot1\config

The problem is more general ... any opam spawned process will have all of the cygpath logic (etc.) disappear when --no-cygwin-setup is used.

[jonahbeckford]

Proposed Solutions

1. Get back to the old behavior for MSYS2 (using cygpath when executing opam subprocesses, etc.). That can't happen unless opam knows about MSYS2:

   opam init --msys2-location=DIR

2. Wrap all opam launched processes with a user-specified command (ex. with-dkml), rather than just the wrap-build-commands/wrap-install-commands/wrap-remove-commands subset. I don't think this is a good idea right now ... it will take a lot of soak testing to get right, and will unnecessarily delay opam 2.2

---

Also, I don't need --msys2-internal-install or --msys2-local-install because I still need with-dkml for DkML users

[kit-ty-kate]

Does it work if you use opam init --cygwin-location=C:\msys64 ?