doc: desc. __MODULES_AUTOINIT_INPROGRESS in man/changes

Author: xdelaruelle

doc/source/changes.rst

@@ -586,6 +586,12 @@ initialization or if the :mconfig:`silent_shell_debug` configuration option is
 set to ``1`` in the :file:`initrc` configuration file. Option is set off by
 default on Modules 5.
 
+During the :subcmd:`autoinit` process, the environment variable
+:envvar:`__MODULES_AUTOINIT_INPROGRESS` is checked and if it is found set to
+``1``, the initialization process immediately ends. If not, this environment
+variable is set to ``1`` which ensures no initialization loop could occur,
+especially when the :mconfig:`set_shell_startup` configuration option is set.
+
 Modulecmd startup
 """""""""""""""""
 
@@ -779,7 +785,8 @@ The following environment variables appeared on Modules 5.
 | in version |                                                                 |
 +============+=================================================================+
 | 5.0        | :envvar:`MODULES_QUARANTINE_SUPPORT`,                           |
-|            | :envvar:`__MODULES_QUARANTINE_SET`                              |
+|            | :envvar:`__MODULES_QUARANTINE_SET`,                             |
+|            | :envvar:`__MODULES_AUTOINIT_INPROGRESS`                         |
 +------------+-----------------------------------------------------------------+
 
 Modules Specific Tcl Commands

doc/source/module.rst

@@ -1815,6 +1815,19 @@ Otherwise ``1`` is returned.
 ENVIRONMENT
 -----------
 
+.. envvar:: __MODULES_AUTOINIT_INPROGRESS
+
+ If set to ``1``, the :subcmd:`autoinit` sub-command process is skipped.
+
+ This environment variable is set to ``1`` by the :subcmd:`autoinit`
+ sub-command after checking it is not set. It ensures no nested initialization
+ of Modules occur. At the end of the processing of the :subcmd:`autoinit`
+ sub-command, :envvar:`__MODULES_AUTOINIT_INPROGRESS` is unset.
+
+ .. only:: html
+
+    .. versionadded:: 5.0
+
 .. envvar:: __MODULES_LMALTNAME
 
  A colon separated list of the alternative names set through