Allow local use of static PyMutex in the C analyzer (python#127102)

Author: ZeroIntensity

Tools/c-analyzer/cpython/_analyzer.py

@@ -280,12 +280,26 @@ def _is_kwlist(decl):
     vartype = ''.join(str(decl.vartype).split())
     return vartype == 'char*[]'
 
+def _is_local_static_mutex(decl):
+    if not hasattr(decl, "vartype"):
+        return False
+
+    if not hasattr(decl, "parent") or decl.parent is None:
+        # We only want to allow local variables
+        return False
+
+    vartype = decl.vartype
+    return (vartype.typespec == 'PyMutex') and (decl.storage == 'static')
 
 def _has_other_supported_type(decl):
     if hasattr(decl, 'file') and decl.file.filename.endswith('.c.h'):
         assert 'clinic' in decl.file.filename, (decl,)
         if decl.name == '_kwtuple':
             return True
+    if _is_local_static_mutex(decl):
+        # GH-127081: Local static mutexes are used to
+        # wrap libc functions that aren't thread safe
+        return True
     vartype = str(decl.vartype).split()
     if vartype[0] == 'struct':
         vartype = vartype[1:]

Tools/c-analyzer/cpython/ignored.tsv

@@ -739,7 +739,6 @@ Modules/expat/xmlrole.c	-	declClose	-
 Modules/expat/xmlrole.c	-	error	-
 
 ## other
-Modules/grpmodule.c	grp_getgrall_impl	getgrall_mutex	-
 Modules/_io/_iomodule.c	-	_PyIO_Module	-
 Modules/_sqlite/module.c	-	_sqlite3module	-
 Modules/clinic/md5module.c.h	_md5_md5	_keywords	-