shiboken: Fix an old enum aliasing error that was never found

While removing the old enums, an unsolved problem
was solved, which had a heuristic workaround before.

A special case needed to be excluded in cppgenerator
where an Anonymous Enum was causing a problem in
morphLastEnumToPython.

Task-number: PYSIDE-1735
Change-Id: Ibd0b8a6194a0005bc49800c12ab5d2626ccf4d8f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
(cherry picked from commit 2b75519adf23ba490e32659ca337b48e7ae4ec41)
Reviewed-by: Christian Tismer <tismer@stackless.com>
Reviewed-by: Shyamnath Premnadh <Shyamnath.Premnadh@qt.io>

3 files changed, 8 insertions, 18 deletions

diff --git a/sources/shiboken6/generator/shiboken/cppgenerator.cpp b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
index 16044df24..38e37c272 100644
--- a/sources/shiboken6/generator/shiboken/cppgenerator.cpp
+++ b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
@@ -5793,9 +5793,14 @@ void CppGenerator::writeEnumInitialization(TextStream &s, const AbstractMetaEnum
             break;
         }
     }
-    s << "// PYSIDE-1735: Resolving the whole enum class at the end for API compatibility.\n"
-        << "EType = morphLastEnumToPython();\n"
-        << enumVarTypeObj << " = EType;\n";
+    if (cppEnum.enumKind() != AnonymousEnum) {
+        s << "// PYSIDE-1735: Resolving the whole enum class at the end for API compatibility.\n"
+            << "EType = morphLastEnumToPython();\n"
+            << enumVarTypeObj << " = EType;\n";
+    } else {
+        s << "// PYSIDE-1735: Skip an Anonymous enum class for Python coercion.\n"
+            << enumVarTypeObj << " = EType;\n";
+    }
     if (cppEnum.typeEntry()->flags()) {
         s << "// PYSIDE-1735: Mapping the flags class to the same enum class.\n"
             << cpythonTypeNameExt(cppEnum.typeEntry()->flags()) << " =\n"
diff --git a/sources/shiboken6/libshiboken/sbkenum.cpp b/sources/shiboken6/libshiboken/sbkenum.cpp
index 212e6fb73..2cc0b935e 100644
--- a/sources/shiboken6/libshiboken/sbkenum.cpp
+++ b/sources/shiboken6/libshiboken/sbkenum.cpp
@@ -1084,17 +1084,6 @@ PyTypeObject *morphLastEnumToPython()
     auto *enumType = lec.enumType;
     // This is temporary; SbkEnumType will be removed, soon.
 
-    // PYSIDE-1735: Decide dynamically if new or old enums will be used.
-    if (useOldEnum)
-        return enumType;
-
-    auto *setp = PepType_SETP(reinterpret_cast<SbkEnumType *>(enumType));
-    if (setp->replacementType) {
-        // For some (yet to fix) reason, initialization of the enums can happen twice.
-        // If that happens, use the existing new type to keep type checks correct.
-        return setp->replacementType;
-    }
-
     auto *scopeOrModule = lec.scopeOrModule;
     static PyObject *enumName = String::createStaticString("IntEnum");
     if (PyType_Check(scopeOrModule)) {
@@ -1180,9 +1169,6 @@ PyTypeObject *morphLastEnumToPython()
         }
     }
 
-    // Protect against double initialization
-    setp->replacementType = newType;
-
     // PYSIDE-1735: Old Python versions can't stand the early enum deallocation.
     static bool old_python_version = is_old_version();
     if (old_python_version)
diff --git a/sources/shiboken6/libshiboken/sbkenum_p.h b/sources/shiboken6/libshiboken/sbkenum_p.h
index d8477b4b3..004f4125f 100644
--- a/sources/shiboken6/libshiboken/sbkenum_p.h
+++ b/sources/shiboken6/libshiboken/sbkenum_p.h
@@ -11,7 +11,6 @@ struct SbkEnumTypePrivate
 {
     SbkConverter *converter;
     const char *cppName;
-    PyTypeObject *replacementType;
 };
 
 extern "C" {