Fix req search when searched mod defines a singular req

Fix extra specifier requirement search when module searched is also
defining a requirement and is the sole module to define it.

Fixes #495

Author: xdelaruelle

NEWS.rst

@@ -19,6 +19,8 @@ Modules 5.3.1 (not yet released)
   fish as configuration snippet for this shell.
 * Fix extra specifier search to evaluate module matching requirement query.
   (fix issue #494)
+* Fix extra specifier requirement search when module searched is also defining
+  a requirement and is the sole module to define it. (fix issue #495)
 
 
 Modules 5.3.0 (2023-05-14)

tcl/modscan.tcl

@@ -264,7 +264,7 @@ proc getModMatchingExtraSpec {pxtlist} {
             prereq-any depends-on always-load load-any try-load switch\
             switch-on switch-off}} {
             if {[dict exists $::g_scanModuleElt $elt]} {
-               foreach modspec [dict get $::g_scanModuleElt $elt] {
+               foreach {modspec values} [dict get $::g_scanModuleElt $elt] {
                   # modEq proc has been initialized in getModules phase #2
                   if {[modEq $modspec $name eqstart 1 5 1]} {
                      # possible duplicate module entry in result list

testsuite/modulefiles.4/extra/1.0

@@ -170,6 +170,9 @@ if {[info exists env(TESTSUITE_EXTRA)]} {
         load7 {
             module load extra/1.0
         }
+        load8 {
+            module load xtfoo/1.0
+        }
         module-err1 {
             module unk foo
         }

testsuite/modules.51-scan/043-extra_spec-require.exp

@@ -340,6 +340,11 @@ setenv_var TESTSUITE_EXTRA load7
 testouterr_cmd sh {avail -t extra load:extra/1.0} OK $tserr
 testouterr_cmd sh {ml av -t extra load:extra/1.0} OK $tserr
 
+# module requiring another one, querying module defining the
+# requirement not the required module
+setenv_var TESTSUITE_EXTRA load8
+testouterr_cmd sh {ml av -t extra load:extra/1.0} OK {}
+
 
 #
 # module erroneous commands