Fix some more duplicate enum to_py utility code names (#5905)

* Fix some more duplicate enum to_py utility code names

It's possible to declare an extern enum multiple times, in a way
that makes the declaration name the same. Therefore, also prefix
declaration names with the module qualified name where possible.

* Use scope mangling

Cython/Compiler/PyrexTypes.py

@@ -5429,19 +5429,26 @@ def type_list_identifier(types):
 ).sub, lambda match: _special_type_characters[match.group(1)])
 
 def type_identifier(type, pyrex=False):
+    scope = None
     decl = type.empty_declaration_code(pyrex=pyrex)
-    return type_identifier_from_declaration(decl)
+    entry = getattr(type, "entry", None)
+    if entry and entry.scope:
+        scope = entry.scope
+    return type_identifier_from_declaration(decl, scope=scope)
 
 _type_identifier_cache = {}
-def type_identifier_from_declaration(decl):
-    safe = _type_identifier_cache.get(decl)
+def type_identifier_from_declaration(decl, scope = None):
+    key = (decl, scope)
+    safe = _type_identifier_cache.get(key)
     if safe is None:
         safe = decl
+        if scope:
+            safe = scope.mangle(prefix="", name=safe)
         safe = re.sub(' +', ' ', safe)
         safe = re.sub(' ?([^a-zA-Z0-9_]) ?', r'\1', safe)
         safe = _escape_special_type_characters(safe)
         safe = cap_length(re.sub('[^a-zA-Z0-9_]', lambda x: '__%X' % ord(x.group(0)), safe))
-        _type_identifier_cache[decl] = safe
+        _type_identifier_cache[key] = safe
     return safe
 
 def cap_length(s, max_prefix=63, max_len=1024):

tests/run/cpdef_enums_import.srctree

@@ -41,11 +41,39 @@ cpdef enum NamedEnumType:
 cpdef enum EnumTypeNotInPyx:
     AnotherEnumValue = 500
 
+######## c_enum.h #############
+
+enum CEnum {
+    CEnumVal1, CEnumVal2
+};
+
+######## external_enums1.pxd ######
+
+cdef extern from "c_enum.h":
+    cpdef enum CEnum:
+        CEnumVal1
+        CEnumVal2
+
+######## external_enums1.pyx ######
+
+######## external_enums2.pxd ######
+
+# external_enums1 and external_enums2 expose the same
+# enum - this shouldn't lead to duplicate utility code
+cdef extern from "c_enum.h":
+    cpdef enum CEnum:
+        CEnumVal1
+        CEnumVal2
+
+######## external_enums2.pyx ######
+
 ######## no_enums.pyx ########
 
 from enums cimport *
 from enums_without_pyx cimport *
 cimport enums_same_name
+cimport external_enums1
+cimport external_enums2
 
 def get_named_enum_value():
     return NamedEnumType.NamedEnumValue
@@ -59,6 +87,12 @@ def get_named_without_pyx():
     # This'll generate a warning but return a c int
     return EnumTypeNotInPyx.AnotherEnumValue
 
+def get_external1():
+    return external_enums1.CEnumVal1
+
+def get_external2():
+    return external_enums2.CEnumVal1
+
 ######## import_enums_test.py ########
 
 # We can import enums with a star import.
@@ -81,3 +115,5 @@ assert no_enums.get_named_enum_value() == NamedEnumType.NamedEnumValue
 assert no_enums.get_named_without_pyx() == 500
 
 assert no_enums.get_from_enums_same_name() == enums_same_name.NamedEnumType.Value
+
+assert no_enums.get_external1() == no_enums.get_external2()