No non-zero exit code when running show over a non-existent module

[xdelaruelle]

Hello Lmod Team,

To be more in line with Lmod, I have made modulecmd.tcl command return a non-zero exit code when a module evaluation fails. This is a regular behavior for any kind of command when something goes wrong, like for instance in our field when trying to evaluate a module that does not exist.

I am working to adapt EasyBuild to make it fit this behavior change in Environment Modules v5.5 (easybuilders/easybuild-framework#4739) and I found something that may be of interest for you.

Describe the issue
EasyBuild is internally running the show sub-command to determine if a module exist or not.

When trying to load a non-existent module, the lmod script sets a non-zero exit code.

But when running the show sub-command, the lmod script sets a zero exit code whether the module exist or not.

To Reproduce

$ $LMOD_CMD bash --version

Modules based on Lua: Version 8.7.55 (8.7.55-5-g1f416cc2a) 2025-01-08 07:32 +01:00
    by Robert McLay [email protected]

$ $LMOD_CMD bash load unknown_module
Lmod has detected the following error:  The following module(s) are unknown: "unknown_module"

Please check the spelling or version number. Also try "module spider ..."
It is also possible your cache file is out-of-date; it may help to try:
  $ module --ignore_cache load "unknown_module"

Also make sure that all modulefiles written in TCL start with the string #%Module




false
$ echo $?
1
$ $LMOD_CMD bash show unknown_module
Lmod Warning:  Failed to find the following module(s): "unknown_module" in your MODULEPATH
Try:

    $ module spider unknown_module

to see if the module(s) are available across all compilers and MPI implementations.



MODULEPATH=/usr/share/Modules/modulefiles:/etc/modulefiles:/usr/share/modulefiles;
export MODULEPATH;
_ModuleTable001_=X01vZHVsZVRhYmxlXyA9IHsKTVR2ZXJzaW9uID0gMywKY19yZWJ1aWxkVGltZSA9IDcyMDAuMCwKY19zaG9ydFRpbWUgPSAwLjA2NjI1MTAzOTUwNTAwNSwKZGVwdGhUID0ge30sCmZhbWlseSA9IHt9LAptVCA9IHt9LAptcGF0aEEgPSB7CiIvdXNyL3NoYXJlL01vZHVsZXMvbW9kdWxlZmlsZXMiLCAiL2V0Yy9tb2R1bGVmaWxlcyIsICIvdXNyL3NoYXJlL21vZHVsZWZpbGVzIiwKfSwKc3lzdGVtQmFzZU1QQVRIID0gIi91c3Ivc2hhcmUvTW9kdWxlcy9tb2R1bGVmaWxlczovZXRjL21vZHVsZWZpbGVzOi91c3Ivc2hhcmUvbW9kdWxlZmlsZXMiLAp9Cg==;
export _ModuleTable001_;
_ModuleTable_Sz_=1;
export _ModuleTable_Sz_;
$ echo $?
0

Expected behavior
As show sub-command makes a module evaluation like load sub-command, it may be interesting to produce an error (and make lmod script sets a non-zero exit code) when trying to evaluate a non-exiting module.

Desktop (please complete the following information):

• OS: Linux
• Linux distribution: Fedora 40
• Lmod Version: 8.7.55

[rtmclay]

Thanks very much for reporting this issue. I have uploaded branch IS743-show to github that fixes this for me. This change comes down to changing the warning to an error when show cannot find a module.

@xdelaruelle : Please test out this branch if you get the change and report back
@boegel Could you also test this change with easybuild

Thanks!

[xdelaruelle]

Many thanks Robert. I have test the new branch and it gives me the expected result with the show sub-command.

I have also run the modules and modulestool sections of the easybuild-framework testsuite against this new Lmod version. With regular easybuild-framework code from 5.0.x branch, tests test_exist and test_modpath_extensions_for fail. But with patch proposed on easybuilders/easybuild-framework#4739, all tests pass.

Input from @boegel is important to determine if this change does not break all existing installation of EasyBuild using Lmod if people decide to update Lmod to the latest version.