Ensure user fully qualify the modules they use

When managing a vast software catalog accessible by multiple users, it is often desired that these users understand exactly what are the software they enable in their environment. This is especially important when new software versions are introduced in the catalog.

On a regular Modules installation, if multiple versions of a given module are available, latest version is selected when user load this software module by specifying its generic name (module load software). So when a new version is installed for software, users automatically end up with this new version enabled in their environment.

Depending on software, a precise version control may be required to avoid issues. In this case the implicit default version selection done by Modules is not desired. This recipe describe the way to handle this kind of situation.


Starting version 4.3 of Modules, a new option called implicit_default is introduced. When enabled (which means configuration option is set to 1) if a module is specified by its generic name an implicit default is automatically defined (latest version) if no explicit default is defined. When implicit_default configuration option is disabled (when set to 0), no implicit default is computed and an error is returned to user in case module has been specified by its generic name but no default version has been set.

So to ensure user fully qualify the modules they use, this implicit_default configuration option should be disabled. It could be achieved by setting the option in the initrc file installed in the configuration directory (or in the modulerc file installed in the initialization script directory if this location is preferred).


module config implicit_default 0

It may be desired to lock this option, to ensure users do not alter it afterward. The locked_configs configuration option fills this need. By setting this option and the implicit_default in a site-specific configuration script, users will not be able to change the implicit_default behavior you configure.

# disable implicit_default option
setConf implicit_default 0

# forbid `implicit_default` config option superseding
lappendConf locked_configs implicit_default

Compatible with Modules v4.3+


Create site-specific configuration directory if it does not exist yet:

$ mkdir /etc/environment-modules

Then copy there the initialization RC file of this recipe:

$ cp example/ensure-user-qualify-modules/initrc /etc/environment-modules/

Or if you want to enforce the implicit_default disablement setup for users, copy there the site-specific configuration script of this recipe:

$ cp example/ensure-user-qualify-modules/siteconfig.tcl /etc/environment-modules/

If you currently use Modules version 4.3, copy the configuration script specific to this version:

$ cp example/ensure-user-qualify-modules/siteconfig.tcl-4.3 /etc/environment-modules/siteconfig.tcl


Defined location for the site-specific configuration script may vary from one installation to another. To determine the expected location for this file on your setup, check the value of the siteconfig option:

$ module config siteconfig

Once file is installed, you could verify option value is correct:

$ module config implicit_default
Modules Release 4.3.0 (2019-07-26)

- Config. name ---------.- Value (set by if default overridden) ---------------
implicit_default          0 (locked)

Usage example

Enable the modulepath where the example modulefiles are located:

$ module use example/ensure-user-qualify-modules/modulefiles

Attempt to load a module, which does not defined a default version, by its generic name:

$ module load -v softa
ERROR: No default version defined for 'softa'

Load succeed if module is fully qualified:

$ module load -v softa/1
Loading softa/1

For modules which define explicitly a default version, they can still be loaded by their generic name:

$ module load -v softb
Loading softb/1