Zulip Chat Archive

Stream: general

Topic: failed to start child process

Scott Morrison (Jul 25 2018 at 06:07):

I have a student who can't run leanpkg on Windows: leanpkg.bat new test says: "failed to start child process", and doesn't create a new directory.

Scott Morrison (Jul 25 2018 at 06:07):

Has anyone experienced this, and knows the fix?

Scott Morrison (Jul 25 2018 at 06:07):

I know nothing about Windows anymore.

Johan Commelin (Jul 25 2018 at 06:27):

Has anyone experienced this, and knows the fix?

The fix would obviously be to wipe Windows and install a proper OS.

Minchao Wu (Jul 25 2018 at 07:53):

@Scott Morrison one of my colleagues has experienced this. The simplest solution would be using Git Bash if Git is installed.

Kevin Buzzard (Jul 25 2018 at 09:09):

I've had several problems with git on Windows. There appears to be more than one canonical installation of git.

Chris Hughes (Jul 25 2018 at 09:45):

I always get that error if I use the windows command line instead of Msys.

Kevin Buzzard (Jul 25 2018 at 09:52):

The mantra I tell Windows users is msys2, git, lean binary, set msys2 path variable so it can see git and leanpkg, then follow instructions in reference manual

Kevin Buzzard (Jul 25 2018 at 09:53):

Oh -- and don't put lean in a directory whose full name has a space in

Scott Morrison (Jul 25 2018 at 10:13):

We found yet another solution: activate the "Linux Subsystem for Windows", install the "Ubuntu" app, and use elan there. It was incredibly painless and fast (15 minutes?)

Mario Carneiro (Jul 25 2018 at 10:22):

really? I've never had much success with WSL

Olli (Sep 12 2018 at 16:53):

Any ideas what the "failed to start child process" might be due to? I am on Windows 10 and I get it when trying to use leanpkg for basically anything. I see that it originates in the C++ code base of Lean itself.

I saw some mentions of this issue in the mailing list, where it was mentioned that it occasionally happens, but for me I'm unable to do almost anything with leanpkg, which means I can't use mathlib as far as I can tell.

I might give using WSL a try, although I'm afraid that configuring VSCode might become a pain in that case.

Olli (Sep 12 2018 at 16:57):

I suppose another thing I could try is compiling Lean from source and hoping that that fixes the issue.

Last updated: Dec 20 2023 at 11:08 UTC