CppTools: Always check for a valid BuiltinEditorDocumentParser*

This fixes a crash if the include hierarchy sidebar is invoked with the
clang code model. BuiltinEditorDocumentParser::get(editorFilePath)
returns 0 in that case.

Task-number: QTCREATORBUG-13553
Change-Id: I9292691c8156bdaaffcac1c3864201ba8a6cbdef
Reviewed-by: Erik Verbruggen <erik.verbruggen@theqtcompany.com>

src/plugins/cppeditor/cppincludehierarchymodel.cpp

@@ -40,6 +40,7 @@
 
 #include <cplusplus/CppDocument.h>
 #include <utils/fileutils.h>
+#include <utils/qtcassert.h>
 
 #include <QSet>
 
@@ -183,8 +184,9 @@ void CppIncludeHierarchyModel::fetchMore(const QModelIndex &parent)
         }
 
         if (item == m_includesItem) {
-            const Snapshot editorDocumentSnapshot
-                = BuiltinEditorDocumentParser::get(editorFilePath)->snapshot();
+            auto *parser = BuiltinEditorDocumentParser::get(editorFilePath);
+            QTC_ASSERT(parser, return);
+            const Snapshot editorDocumentSnapshot = parser->snapshot();
             buildHierarchyIncludes_helper(parentItem->filePath(), parentItem,
                                           editorDocumentSnapshot, &cyclic);
         } else {
@@ -284,7 +286,9 @@ void CppIncludeHierarchyModel::buildHierarchyIncludes(const QString &currentFile
         return;
 
     const QString editorFilePath = m_editor->document()->filePath();
-    const Snapshot snapshot = BuiltinEditorDocumentParser::get(editorFilePath)->snapshot();
+    auto *parser = BuiltinEditorDocumentParser::get(editorFilePath);
+    QTC_ASSERT(parser, return);
+    const Snapshot snapshot = parser->snapshot();
     QSet<QString> cyclic;
     buildHierarchyIncludes_helper(currentFilePath, m_includesItem, snapshot, &cyclic);
 }

src/plugins/cpptools/cppmodelmanager_test.cpp

@@ -946,7 +946,8 @@ void CppToolsPlugin::test_modelmanager_precompiled_headers()
         QCOMPARE(Core::DocumentModel::openedDocuments().size(), 1);
         QVERIFY(mm->isCppEditor(editor));
 
-        BuiltinEditorDocumentParser *parser = BuiltinEditorDocumentParser::get(fileName);
+        auto *parser = BuiltinEditorDocumentParser::get(fileName);
+        QVERIFY(parser);
         parser->setUsePrecompiledHeaders(true);
         parser->update(mm->workingCopy());
 

src/plugins/cpptools/cppsourceprocessor_test.cpp

@@ -143,7 +143,7 @@ void CppToolsPlugin::test_cppsourceprocessor_includes_cyclic()
 
     // Check editor snapshot
     const QString filePath = editor->document()->filePath();
-    BuiltinEditorDocumentParser *parser = BuiltinEditorDocumentParser::get(filePath);
+    auto *parser = BuiltinEditorDocumentParser::get(filePath);
     QVERIFY(parser);
     Snapshot snapshot = parser->snapshot();
     QCOMPARE(snapshot.size(), 3); // Configuration file included

src/plugins/designer/gotoslot_test.cpp

@@ -196,9 +196,14 @@ public:
         }
 
         // Compare
-        const Document::Ptr cppDocument = BuiltinEditorDocumentParser::get(cppFile)->document();
+        BuiltinEditorDocumentParser *cppDocumentParser = BuiltinEditorDocumentParser::get(cppFile);
+        QVERIFY(cppDocumentParser);
+        const Document::Ptr cppDocument = cppDocumentParser->document();
         QVERIFY(checkDiagsnosticMessages(cppDocument));
-        const Document::Ptr hDocument = BuiltinEditorDocumentParser::get(hFile)->document();
+
+        BuiltinEditorDocumentParser *hDocumentParser = BuiltinEditorDocumentParser::get(hFile);
+        QVERIFY(hDocumentParser);
+        const Document::Ptr hDocument = hDocumentParser->document();
         QVERIFY(checkDiagsnosticMessages(hDocument));
 
         QVERIFY(documentContainsFunctionDefinition(cppDocument,