The automated module handling mode (new feature for the future version 4.2) has gain a new mechanism: Dependent module Unload (DepUn). I have tried to improve and clarify the explanation on all of this:

An automatic management of the dependencies between modulefiles has been added and it is called automated module handling mode. This new mode consists in additional actions triggered when loading or unloading a modulefile to satisfy the constraints it declares.

When loading a modulefile, following actions are triggered:

• Requirement Load (ReqLo): load of the modulefiles declared as a prereq of the loading modulefile.

• Dependent Reload (DepRe): reload of the modulefiles declaring a prereq onto loaded modulefile or declaring a prereq onto a modulefile part of this reloading batch.

When unloading a modulefile, following actions are triggered:

• Dependent Unload (DepUn): unload of the modulefiles declaring a non-optional prereq onto unloaded modulefile or declaring a non-optional prereq onto a modulefile part of this unloading batch. A prereq modulefile is considered optional if the prereq definition order is made of multiple modulefiles and at least one alternative modulefile is loaded.

• Useless Requirement Unload (UReqUn): unload of the prereq modulefiles that have been automatically loaded for either the unloaded modulefile, an unloaded dependent modulefile or a modulefile part of this useless requirement unloading batch. Modulefiles are added to this unloading batch only if they are not required by any other loaded modulefiles. MODULES_LMNOTUASKED environment variable helps to keep track of these automatically loaded modulefiles and to distinguish them from modulefiles asked by user.

• Dependent Reload (DepRe): reload of the modulefiles declaring a conflict or an optional prereq onto either the unloaded modulefile, an unloaded dependent or an unloaded useless requirement or declaring a prereq onto a modulefile part of this reloading batch.

In case a loaded modulefile has some of its declared constraints unsatisfied (pre-required modulefile not loaded or conflicting modulefile loaded for instance), this loaded modulefile is excluded from the automatic reload actions described above.

For the specific case of the switch sub-command, where a modulefile is unloaded to then load another modulefile. Dependent modulefiles to Unload are merged into the Dependent modulefiles to Reload that are reloaded after the load of the switched-to modulefile.

This automated module handling mode integrates concepts (like the Dependent Reload mechanism) of the Flavours extension, which was designed for Modules compatibility version. As a whole, automated module handling mode can be seen as a generalization and as an expansion of the Flavours concepts.