shiboken6: Do not crash when class cannot be found in the overload sorter

Print an error message instead.
As a drive-by, add a helper to create a class-qualified signature
for error reporting purposes to AbstractMetaFunction.

Task-number: PYSIDE-1684
Change-Id: I8417f405b4ce1b64060aad0696e5d328869cb83e
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
(cherry picked from commit 1e7f97e082d5430ff8323bc58c480d00a4f64852)
Reviewed-by: Christian Tismer <tismer@stackless.com>

6 files changed, 33 insertions, 9 deletions

diff --git a/sources/shiboken6/ApiExtractor/abstractmetafunction.cpp b/sources/shiboken6/ApiExtractor/abstractmetafunction.cpp
index f1bcc3bbb..fc79a8c2a 100644
--- a/sources/shiboken6/ApiExtractor/abstractmetafunction.cpp
+++ b/sources/shiboken6/ApiExtractor/abstractmetafunction.cpp
@@ -505,6 +505,15 @@ QString AbstractMetaFunction::signature() const
     return d->signature();
 }
 
+QString AbstractMetaFunction::classQualifiedSignature() const
+{
+    QString result;
+    if (d->m_implementingClass)
+        result += d->m_implementingClass->qualifiedCppName() + u"::"_qs;
+    result += signature();
+    return result;
+}
+
 bool AbstractMetaFunction::isConstant() const
 {
     return d->m_constant;
diff --git a/sources/shiboken6/ApiExtractor/abstractmetafunction.h b/sources/shiboken6/ApiExtractor/abstractmetafunction.h
index 9001c16e5..1682b0493 100644
--- a/sources/shiboken6/ApiExtractor/abstractmetafunction.h
+++ b/sources/shiboken6/ApiExtractor/abstractmetafunction.h
@@ -284,6 +284,8 @@ public:
 
     QStringList introspectionCompatibleSignatures(const QStringList &resolvedArguments = QStringList()) const;
     QString signature() const;
+    /// Return a signature qualified by class name, for error reporting.
+    QString classQualifiedSignature() const;
 
     bool isConstant() const;
     void setConstant(bool constant);
diff --git a/sources/shiboken6/ApiExtractor/messages.cpp b/sources/shiboken6/ApiExtractor/messages.cpp
index 00d9dd816..ffca9bcd8 100644
--- a/sources/shiboken6/ApiExtractor/messages.cpp
+++ b/sources/shiboken6/ApiExtractor/messages.cpp
@@ -272,9 +272,8 @@ QString msgShadowingFunction(const AbstractMetaFunction *f1,
     auto f2Class = f2->implementingClass();
     QString result;
     QTextStream str(&result);
-    str << f2Class->sourceLocation() << "Shadowing: " << f1->implementingClass()->name()
-        << "::" << f1->signature() << " and " << f2Class->name() << "::"
-        << f2->signature();
+    str << f2Class->sourceLocation() << "Shadowing: " << f1->classQualifiedSignature()
+        << " and " << f2->classQualifiedSignature();
     return result;
 }
 
@@ -832,3 +831,12 @@ QString msgInvalidTargetLanguageApiName(const QString &name)
     return u"Invalid target language API name \""_qs
            + name + u"\"."_qs;
 }
+
+QString msgArgumentClassNotFound(const AbstractMetaFunctionCPtr &func,
+                                 const TypeEntry *t)
+{
+    QString result;
+    QTextStream(&result) << "Internal Error: Class \"" <<  t->qualifiedCppName()
+        << "\" for \"" << func->classQualifiedSignature() << "\" not found!";
+    return result;
+}
diff --git a/sources/shiboken6/ApiExtractor/messages.h b/sources/shiboken6/ApiExtractor/messages.h
index 7e6fd87a5..c0127f83e 100644
--- a/sources/shiboken6/ApiExtractor/messages.h
+++ b/sources/shiboken6/ApiExtractor/messages.h
@@ -239,4 +239,7 @@ QString msgDuplicateBuiltInTypeEntry(const QString &name);
 QString msgDuplicateTypeEntry(const QString &name);
 QString msgInvalidTargetLanguageApiName(const QString &name);
 
+QString msgArgumentClassNotFound(const AbstractMetaFunctionCPtr &func,
+                                 const TypeEntry *t);
+
 #endif // MESSAGES_H
diff --git a/sources/shiboken6/generator/shiboken/cppgenerator.cpp b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
index cc77dc799..47bc3d832 100644
--- a/sources/shiboken6/generator/shiboken/cppgenerator.cpp
+++ b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
@@ -996,10 +996,8 @@ QString CppGenerator::virtualMethodReturn(TextStream &s, const ApiExtractorResul
     QString errorMessage;
     const auto defaultReturnExpr = minimalConstructor(api, returnType, &errorMessage);
     if (!defaultReturnExpr.has_value()) {
-        QString errorMsg = QLatin1String(__FUNCTION__) + QLatin1String(": ");
-        if (const AbstractMetaClass *c = func->implementingClass())
-            errorMsg += c->qualifiedCppName() + QLatin1String("::");
-        errorMsg += func->signature();
+        QString errorMsg = QLatin1String(__FUNCTION__) + u": "_qs
+                           + func->classQualifiedSignature();
         errorMsg = msgCouldNotFindMinimalConstructor(errorMsg,
                                                      func->type().cppSignature(),
                                                      errorMessage);
diff --git a/sources/shiboken6/generator/shiboken/overloaddata.cpp b/sources/shiboken6/generator/shiboken/overloaddata.cpp
index 103770396..1eb06b10b 100644
--- a/sources/shiboken6/generator/shiboken/overloaddata.cpp
+++ b/sources/shiboken6/generator/shiboken/overloaddata.cpp
@@ -37,6 +37,8 @@
 #include "ctypenames.h"
 #include "pytypenames.h"
 #include "textstream.h"
+#include "exception.h"
+#include "messages.h"
 
 #include <QtCore/QDir>
 #include <QtCore/QFile>
@@ -287,8 +289,10 @@ void OverloadDataRootNode::sortNextOverloads(const ApiExtractorResult &api)
 
         // Process inheritance relationships
         if (targetType.isValue() || targetType.isObject()) {
-            auto metaClass = AbstractMetaClass::findClass(api.classes(),
-                                                          targetType.typeEntry());
+            auto *te = targetType.typeEntry();
+            auto metaClass = AbstractMetaClass::findClass(api.classes(), te);
+            if (!metaClass)
+                throw Exception(msgArgumentClassNotFound(m_overloads.constFirst(), te));
             const AbstractMetaClassList &ancestors = metaClass->allTypeSystemAncestors();
             for (const AbstractMetaClass *ancestor : ancestors) {
                 QString ancestorTypeName = ancestor->typeEntry()->name();