doc: desc. __MODULES_LMPREREQPATH env var

Author: xdelaruelle

NEWS.rst

@@ -41,7 +41,8 @@ Modules 5.5.0 (not yet released)
   :mfcmd:`depends-on`, :mfcmd:`prereq`, :mfcmd:`prereq-all` and
   :mfcmd:`prereq-any` modulefile commands. When this option is set, required
   module should be located in a path listed in the specified list or in an
-  enabled modulepath matching one path of the list.
+  enabled modulepath matching one path of the list. This information is
+  recorded in loaded environment in :envvar:`__MODULES_LMPREREQPATH` variable.
 * Add :mfcmd:`lsb-release` modulefile command to get certain Linux Standard
   Base (LSB) information. It accepts to following sub-commands: ``id``,
   ``codename`` and ``release``.

doc/source/changes.rst

@@ -994,7 +994,8 @@ The following environment variables appeared on Modules 5.
 +------------+-----------------------------------------------------------------+
 | 5.5        | :envvar:`MODULES_HIDE_AUTO_LOADED`, :envvar:`MODULES_LOGGER`,   |
 |            | :envvar:`MODULES_LOGGED_EVENTS`,                                |
-|            | :envvar:`MODULES_CONFLICT_UNLOAD`                               |
+|            | :envvar:`MODULES_CONFLICT_UNLOAD`,                              |
+|            | :envvar:`__MODULES_LMPREREQPATH`                                |
 +------------+-----------------------------------------------------------------+
 
 Modules Specific Tcl Commands

doc/source/module.rst

@@ -3835,6 +3835,26 @@ ENVIRONMENT
     .. versionchanged:: 5.0
        Variable renamed from ``MODULES_LMPREREQ`` to ``__MODULES_LMPREREQ``
 
+.. envvar:: __MODULES_LMPREREQPATH
+
+ A colon separated list of the :mfcmd:`prereq` statements set with a specific
+ ``--modulepath`` option defined by all loaded *modulefiles*. Each element in
+ this list starts by the name of the loaded *modulefile* declaring the
+ pre-requirement followed by the name of all modulefiles it declares a
+ :mfcmd:`prereq` with and their specific modulepath. These loaded modulefiles,
+ pre-required modulefile names and specific modulepaths set are separated by
+ the ampersand character. When a :mfcmd:`prereq` statement is composed of
+ multiple modulefiles or multiple specific modulepaths, these names are
+ separated by the pipe character.
+
+ This environment variable is intended for :command:`module` command internal
+ use to get knowledge of the pre-requirement declared by the loaded
+ *modulefiles* in order to keep environment consistent.
+
+ .. only:: html
+
+    .. versionadded:: 5.5
+
 .. envvar:: __MODULES_LMREFRESH
 
  A colon separated list of the loaded modules that are qualified for refresh