[BUG] check-license failing sometimes

[artemiogr97]

Bug description

The pre-commit hook for license checking is failing sometimes.
I had not been able to understand when it happens, from the log it seems like my stdlib.mojopkg is not found but running an script in the same terminal by doing mojo path/to/my/script works (and the stdlib in my build directory is used).

Steps to reproduce

just do git commit, I get the following log:

[INFO] Stashing unstaged files to /home/temo/.cache/pre-commit/patch1714911965-57965.
mojo-format..............................................................Passed
check-docstrings.........................................................Passed
check-license............................................................Failed
- hook id: check-license
- exit code: 1

/home/temo/repos/mojo/build/stdlib.mojopkg:0:0: error: attempting to skip 4 bytes when only 0 remain
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:14:1: error: unable to load package '/home/temo/repos/mojo/build/stdlib.mojopkg'
import sys
^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:14:8: error: unable to locate module 'sys'
import sys
       ^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:15:6: error: unable to locate module 'pathlib'
from pathlib import Path
     ^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:19:17: error: use of unknown declaration 'String'
alias LICENSE = String(
                ^~~~~~
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:27:11: error: could not find an 'object' type
def main():
          ^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:27:11: error: could not find an 'Error' type
def main():
          ^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:27:5: error: could not find an 'object' type
def main():
    ^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:27:5: error: unable to locate module 'builtin'
def main():
    ^
/home/temo/repos/mojo/stdlib/scripts/check-licenses.mojo:28:1: error: 
    target_paths = sys.argv()
^
/home/temo/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo: error: failed to parse the provided Mojo source module

System information

- What OS did you do install Mojo on ?
WSL ubuntu 22.04.4 in windows 11
- Provide version information for Mojo by pasting the output of `mojo -v`
mojo 2024.5.323 (1d9276ea)
- Provide Modular CLI version by pasting the output of `modular -v`
modular 0.7.2 (d0adc668)

[artemiogr97]

@gabrieldemarmiesse any ideas? maybe using a python hook would be a workaround for now?

[gabrieldemarmiesse]

Mhhh indeed that's hard to know what was going on. My guess is that at that time, either the stdlib.mojopkg wasn't build yet, or the environment variable setting the path to the stdlib.mojopkg wasn't set correctly. I must admit it's hard to find out what exactly happened without being able to reproduce

[artemiogr97]

yep that was my guess too, but I ran both commands in the same terminal one after the other (I tried git commit and then mojo path/to/my/script and also mojo path/to/my/script and then git commit, in both cases git commit failed but the other command succeeded), it's really weird

[artemiogr97]

I found the issue, I did what is mentioned in development.md:

mojo/stdlib/docs/development.md

Lines 249 to 262 in 00528f4

	### Bonus tip: fast feedback loop
	If you like a fast feedback loop, try installing the file watcher `entr`, which
	you can get with `sudo apt install entr` on Linux, or `brew install entr` on
	macOS. Now run:
	```bash
	export MODULAR_MOJO_NIGHTLY_IMPORT_PATH=../build
	ls **/*.mojo | entr sh -c "./scripts/build-stdlib.sh && mojo main.mojo"
	```
	Now, every time you save a Mojo file, it packages the standard library and
	runs `main.mojo`.

Every time I commit entr tries to compile so the pre-commit is ran while compiling stdlib, so maybe it is worth adding a comment in the doc @gabrieldemarmiesse ?

[gabrieldemarmiesse]

Nice one! Indeed, that makes sense that it didn't work. Yes feel free to open a PR with a comment in the guide

[ematejska]

Thanks for this issue!