BUG: f2py: better handle filtering of public/private subroutines

Don't mistake public/private declarations of F90 subroutines for variables
when the corresponding subroutines are filtered by use of only:.
Also, handle modules with no public variables or subroutines, caused by
the filtering.

Closes numpygh-26920.

Author: m-weigand

numpy/f2py/auxfuncs.py

@@ -36,16 +36,15 @@
     'isintent_nothide', 'isintent_out', 'isintent_overwrite', 'islogical',
     'islogicalfunction', 'islong_complex', 'islong_double',
     'islong_doublefunction', 'islong_long', 'islong_longfunction',
-    'ismodule', 'ismoduleroutine', 'isoptional', 'isprivate', 'isrequired',
-    'isroutine', 'isscalar', 'issigned_long_longarray', 'isstring',
-    'isstringarray', 'isstring_or_stringarray', 'isstringfunction',
-    'issubroutine', 'get_f2py_modulename',
-    'issubroutine_wrap', 'isthreadsafe', 'isunsigned', 'isunsigned_char',
-    'isunsigned_chararray', 'isunsigned_long_long',
-    'isunsigned_long_longarray', 'isunsigned_short',
-    'isunsigned_shortarray', 'l_and', 'l_not', 'l_or', 'outmess',
-    'replace', 'show', 'stripcomma', 'throw_error', 'isattr_value',
-    'getuseblocks', 'process_f2cmap_dict'
+    'ismodule', 'ismoduleroutine', 'isoptional', 'isprivate', 'isvariable',
+    'isrequired', 'isroutine', 'isscalar', 'issigned_long_longarray',
+    'isstring', 'isstringarray', 'isstring_or_stringarray', 'isstringfunction',
+    'issubroutine', 'get_f2py_modulename', 'issubroutine_wrap', 'isthreadsafe',
+    'isunsigned', 'isunsigned_char', 'isunsigned_chararray',
+    'isunsigned_long_long', 'isunsigned_long_longarray', 'isunsigned_short',
+    'isunsigned_shortarray', 'l_and', 'l_not', 'l_or', 'outmess', 'replace',
+    'show', 'stripcomma', 'throw_error', 'isattr_value', 'getuseblocks',
+    'process_f2cmap_dict'
 ]
 
 
@@ -518,6 +517,15 @@ def isprivate(var):
     return 'attrspec' in var and 'private' in var['attrspec']
 
 
+def isvariable(var):
+    # heuristic to find public/private declarations of filtered subroutines
+    if len(var) == 1 and 'attrspec' in var and \
+            var['attrspec'][0] in ('public', 'private'):
+        is_var = False
+    else:
+        is_var = True
+    return is_var
+
 def hasinitvalue(var):
     return '=' in var
 

numpy/f2py/f90mod_rules.py

@@ -110,11 +110,16 @@ def dadd(line, s=doc):
                 notvars.append(b['name'])
         for n in m['vars'].keys():
             var = m['vars'][n]
-            if (n not in notvars) and (not l_or(isintent_hide, isprivate)(var)):
+
+            if (n not in notvars and isvariable(var)) and (not l_or(isintent_hide, isprivate)(var)):
                 onlyvars.append(n)
                 mfargs.append(n)
         outmess('\t\tConstructing F90 module support for "%s"...\n' %
                 (m['name']))
+        if len(onlyvars) == 0 and len(notvars) == 1 and m['name'] in notvars:
+            outmess(f"\t\t\tSkipping {m['name']} since there are no public vars/func in this module...\n")
+            continue
+
         if m['name'] in usenames and not contains_functions_or_subroutines:
             outmess(f"\t\t\tSkipping {m['name']} since it is in 'use'...\n")
             continue