follow Lmod rules for path updates

Makefile

@@ -443,6 +443,7 @@ sed -e 's|@prefix@|$(prefix)|g' \
 	-e 's|@sourcecache@|$(setsourcecache)|g' \
 	-e 's|@searchmatch@|$(searchmatch)|g' \
 	-e 's|@wa277@|$(setwa277)|g' \
+	-e 's|@pathentryreorder@|$(pathentryreorder)|g' \
 	-e 's|@icase@|$(icase)|g' \
 	-e 's|@nearlyforbiddendays@|$(nearlyforbiddendays)|g' \
 	-e 's|@tagabbrev@|$(tagabbrev)|g' \

configure

@@ -34,7 +34,7 @@ multilibsupport libdir64 libdir32 versioning silentshdbgsupport \
 setshellstartup quarantinesupport autohandling availindepth implicitdefault \
 extendeddefault moduleshome initconfin pager pageropts verbosity color \
 darkbgcolors lightbgcolors termbg lockedconfigs icase unloadmatchorder \
-searchmatch modulepath loadedmodules quarantinevars wa277 advversspec ml \
+searchmatch modulepath loadedmodules quarantinevars wa277 pathentryreorder advversspec ml \
 windowssupport nearlyforbiddendays implicitrequirement tagabbrev \
 tagcolorname mcookieversioncheck availoutput availterseoutput listoutput \
 listterseoutput editor variantshortcut bashcompletiondir fishcompletiondir \
@@ -79,6 +79,7 @@ extendeddefault=y
 advversspec=y
 ml=y
 wa277=n
+pathentryreorder=n
 loadedmodules=
 quarantinevars=
 binsearchpath=/usr/bin:/bin:/usr/local/bin
@@ -803,6 +804,9 @@ for arg in "$@"; do
    --enable-mcookie-version-check*|--disable-mcookie-version-check)
       # shellcheck disable=SC2034
       mcookieversioncheck=$(get_feature_value "$arg") ;;
+   --enable-path-entry-reorder*|--disable-path-entry-reorder)
+      # shellcheck disable=SC2034
+      pathentryreorder=$(get_feature_value "$arg") ;;
    --with-bin-search-path=*|--without-bin-search-path)
       binsearchpath=$(get_package_value "$arg") ;;
    --with-moduleshome=*|--without-moduleshome)

doc/source/module.rst

@@ -1370,6 +1370,30 @@ Module Sub-Commands
   sub-command when changing this configuration option from its default value.
   See :envvar:`MODULES_PAGER` description for details.
 
+ .. mconfig:: path_entry_reorder
+
+  Change order of entry in a path-like environment variable, when 
+  :mfcmd:`prepend-path`, :mfcmd:`append-path` or :subcmd:`use` target 
+  a path entry that is already defined in the environment variable.
+
+  The default behavior of :mfcmd:`prepend-path`, :mfcmd:`append-path` and
+  :subcmd:`use` is not to update the value if a path-like environment
+  variable, if they target a path entry that is already defined in the
+  environment variable. If this config option is set to 1, an existing
+  path entry is moved to the beginning respective end unless duplicates
+  are allowed. This is the default behavior of Lmod.
+
+  Default value is 0. It can be changed at installation time with
+  :instopt:`--with-path-entry-reorder` option. The
+  :envvar:`MODULES_PATH_ENTRY_REORDER` environment variable is defined by
+  :subcmd:`config` sub-command when changing this configuration option from
+  its default value. See :envvar:`MODULES_PATH_ENTRY_REORDER` description
+  for details.
+
+  .. only:: html
+
+     .. versionadded:: 5.x
+
  .. mconfig:: protected_envvars
 
   Prevents any modification of listed environment variables (colon `:`
@@ -5267,6 +5291,19 @@ ENVIRONMENT
     .. versionchanged:: 5.5
        No pager when :file:`modulecmd.tcl` is run for scripting languages
 
+.. envvar:: MODULES_PATH_ENTRY_REORDER
+
+ The default behavior of :mfcmd:`prepend-path`, :mfcmd:`append-path` and
+ :subcmd:`use` is not to update the value if a path-like environment
+ variable, if they target a path entry that is already defined in the
+ environment variable. If this config option is set to 1, an existing
+ path entry is moved to the beginning respective end unless duplicates
+ are allowed. This is the default behavior of Lmod.
+
+ .. only:: html
+
+    .. versionadded:: 5.x
+
 .. envvar:: MODULES_PROTECTED_ENVVARS
 
  A colon separated list of environment variable names that should not be

init/Makefile

@@ -136,7 +136,7 @@ comp_lint_opts := -a -i --all --icase
 comp_modtosh_opts := --auto --no-auto --force -f --icase -i
 comp_path_opts := -d --delim --duplicates
 comp_rm_path_opts := -d --delim --index
-comp_config_opts := --dump-state --reset abort_on_error advanced_version_spec auto_handling avail_indepth avail_output avail_terse_output cache_buffer_bytes cache_expiry_secs collection_pin_version collection_pin_tag collection_target color colors conflict_unload contact editor extended_default extra_siteconfig hide_auto_loaded home icase ignore_cache ignore_user_rc implicit_default implicit_requirement list_output list_terse_output locked_configs logged_events logger mcookie_check mcookie_version_check ml nearly_forbidden_days pager protected_envvars quarantine_support rcfile redirect_output require_via reset_target_state run_quarantine search_match set_shell_startup shells_with_ksh_fpath silent_shell_debug source_cache spider_indepth spider_output spider_terse_output sticky_purge tag_abbrev tag_color_name tcl_linter term_background term_width unique_name_loaded unload_match_order variant_shortcut verbosity wa_277
+comp_config_opts := --dump-state --reset abort_on_error advanced_version_spec auto_handling avail_indepth avail_output avail_terse_output cache_buffer_bytes cache_expiry_secs collection_pin_version collection_pin_tag collection_target color colors conflict_unload contact editor extended_default extra_siteconfig hide_auto_loaded home icase ignore_cache ignore_user_rc implicit_default implicit_requirement list_output list_terse_output locked_configs logged_events logger mcookie_check mcookie_version_check ml nearly_forbidden_days pager protected_envvars quarantine_support rcfile redirect_output require_via reset_target_state run_quarantine search_match set_shell_startup shells_with_ksh_fpath silent_shell_debug source_cache spider_indepth spider_output spider_terse_output sticky_purge tag_abbrev tag_color_name tcl_linter term_background term_width unique_name_loaded unload_match_order variant_shortcut verbosity wa_277 path_entry_reorder
 
 define translate-in-script
 $(ECHO_GEN)
@@ -167,6 +167,7 @@ sed -e 's|@prefix@|$(prefix)|g' \
 	-e 's|@comp_path_opts@|$(comp_path_opts)|g' \
 	-e 's|@comp_rm_path_opts@|$(comp_rm_path_opts)|g' \
 	-e 's|@comp_config_opts@|$(comp_config_opts)|g' \
+	-e 's|@comp_path_entry_reorder@|$(comp_path_entry_reorder)|g' \
 	-e '$(setzshfpathre)' \
 	-e $$'s|@modulerc@|$(modulerc)|g' \
 	-e 's|@modulepath@|$(modulepath)|g' \

tcl/envmngt.tcl.in

@@ -1816,27 +1816,43 @@ proc add-path {cmd mode dflbhv args} {
    set val [get-env $var]
 
    foreach dir $path_list {
-      if {![info exists countarr($dir)] || $allow_dup} {
+      # remove $dir from path only if path_entry_reorder is true and
+      # $dir is already in path and duplicates are NOT allowed.
+      if {[getConf path_entry_reorder] && [info exists countarr($dir)]\
+         && ! $allow_dup} {
+         set mpath_list [split $val $separator]
+         set mpath_list [lsearch -inline -all -not -exact $mpath_list $dir]
+         set val [join $mpath_list $separator]
+      }
+      # add $dir to beginning or end only if path_entry_reorder is true or
+      # $dir is NOT in path or duplicates are allowed.
+      # Please note: if path_entry_reorder is true and duplicates are not
+      # allowed, $dir is not in path ($val) - either it was not in or it
+      # had been removed. Hence we have to add it.
+      if {[getConf path_entry_reorder] || ![info exists countarr($dir)]\
+         || $allow_dup} {
          # ignore env var set empty if no empty entry found in reference
          # counter array (sometimes var is cleared by setting it empty not
          # unsetting it)
          if {$val ne {} || [info exists countarr()]} {
             set sep [expr {$val eq $separator ? {} : $separator}]
             set val [expr {$bhv eq {prepend} ? "$dir$sep$val" :\
-               "$val$sep$dir"}]
+                              "$val$sep$dir"}]
          } else {
             set val $dir
          }
       }
-      if {[info exists countarr($dir)]} {
-         # do not increase counter if bare separator string is added or if
-         # reference count is ignored (--ignore-refcount set) unless if
-         # duplicate mode is enabled (--duplicates set)
-         if {!$val_set_is_delim && (!$ign_refcount || $allow_dup)} {
-            incr countarr($dir)
-         }
-      } else {
+      #### ref-counting
+      # if $dir is NOT in path
+      #    set ref-count 1
+      # else
+      #    do NOT increase counter if bare separator string is added or if
+      #    reference count is ignored (--ignore-refcount set) unless if
+      #    duplicate mode is enabled (--duplicates set)
+      if {![info exists countarr($dir)]} {
          set countarr($dir) 1
+      } elseif {!$val_set_is_delim && (!$ign_refcount || $allow_dup)} {
+         incr countarr($dir)
       }
    }
 
@@ -2054,7 +2070,10 @@ proc getModulesEnvVarGlobList {{loaded_ctx 0}} {
    return $envvar_glob_list
 }
 
-# ;;; Local Variables: ***
-# ;;; mode:tcl ***
-# ;;; End: ***
+# ;;; Local Variables:
+# ;;; Mode: tcl-mode
+# ;;; tcl-indent-level: 3
+# ;;; tcl-continued-indent-level: 3
+# ;;; indent-tabs-mode: nil
+# ;;; End:
 # vim:set tabstop=3 shiftwidth=3 expandtab autoindent:

tcl/init.tcl.in

@@ -111,6 +111,7 @@ array set g_config_defs [list\
       alias indesym sym tag hidden key} {} {} eltlist}\
    list_terse_output {MODULES_LIST_TERSE_OUTPUT {@listterseoutput@} 0 l\
       {header idx variant alias indesym sym tag hidden key} {} {} eltlist}\
+   path_entry_reorder {MODULES_PATH_ENTRY_REORDER @pathentryreorder@ 0 0 b {0 1}}\
    locked_configs {{} {@lockedconfigs@} 0 o}\
    logged_events {MODULES_LOGGED_EVENTS {@loggedevents@} 1 l {auto_eval\
       requested_eval requested_cmd} {} {} eltlist}\

tcl/subcmd.tcl.in

@@ -3148,7 +3148,10 @@ proc cmdModuleSpider {show_oneperline show_mtime show_filter search_filter\
       $search_match $modpath_list {*}$args
 }
 
-# ;;; Local Variables: ***
-# ;;; mode:tcl ***
-# ;;; End: ***
+# ;;; Local Variables:
+# ;;; Mode: tcl-mode
+# ;;; tcl-indent-level: 3
+# ;;; tcl-continued-indent-level: 3
+# ;;; indent-tabs-mode: nil
+# ;;; End:
 # vim:set tabstop=3 shiftwidth=3 expandtab autoindent: