Clang: Ignore certain warnings in header files

We already had this workarounded, but it got lost in the refactorings.

Task-number: QTCREATORBUG-12067
Change-Id: Ie01f9d41f25d17d1b595204748634bc87ef44378
Reviewed-by: Marco Bubke <marco.bubke@theqtcompany.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/plugins/clangcodemodel/clangdiagnosticfilter.cpp

@@ -25,6 +25,10 @@
 
 #include "clangdiagnosticfilter.h"
 
+#include <cpptools/cppprojectfile.h>
+
+#include <utf8stringvector.h>
+
 namespace {
 
 bool isWarningOrNote(ClangBackEnd::DiagnosticSeverity severity)
@@ -41,6 +45,17 @@ bool isWarningOrNote(ClangBackEnd::DiagnosticSeverity severity)
     Q_UNREACHABLE();
 }
 
+bool isBlackListedDiagnostic(const ClangBackEnd::DiagnosticContainer &diagnostic,
+                             bool isHeaderFile)
+{
+    static const Utf8StringVector blackList {
+        Utf8StringLiteral("warning: #pragma once in main file"),
+        Utf8StringLiteral("warning: #include_next in primary source file")
+    };
+
+    return isHeaderFile && blackList.contains(diagnostic.text());
+}
+
 template <class Condition>
 QVector<ClangBackEnd::DiagnosticContainer>
 filterDiagnostics(const QVector<ClangBackEnd::DiagnosticContainer> &diagnostics,
@@ -76,8 +91,13 @@ namespace Internal {
 void ClangDiagnosticFilter::filterDocumentRelatedWarnings(
         const QVector<ClangBackEnd::DiagnosticContainer> &diagnostics)
 {
-    const auto isLocalWarning = [this] (const ClangBackEnd::DiagnosticContainer &diagnostic) {
+    using namespace CppTools;
+    const bool isHeaderFile = ProjectFile::isHeader(ProjectFile::classify(m_filePath));
+
+    const auto isLocalWarning = [this, isHeaderFile]
+            (const ClangBackEnd::DiagnosticContainer &diagnostic) {
         return isWarningOrNote(diagnostic.severity())
+            && !isBlackListedDiagnostic(diagnostic, isHeaderFile)
             && diagnostic.location().filePath() == m_filePath;
     };
 

src/plugins/cpptools/cpptoolsunittestfiles.pri

@@ -4,6 +4,10 @@ contains(CONFIG, dll) {
     DEFINES += CPPTOOLS_STATIC_LIBRARY
 }
 
-HEADERS += $$PWD/senddocumenttracker.h
+HEADERS += \
+    $$PWD/cppprojectfile.h \
+    $$PWD/senddocumenttracker.h \
 
-SOURCES += $$PWD/senddocumenttracker.cpp
+SOURCES += \
+    $$PWD/cppprojectfile.cpp \
+    $$PWD/senddocumenttracker.cpp

tests/unit/unittest/clangdiagnosticfiltertest.cpp

@@ -64,6 +64,7 @@ DiagnosticContainer createDiagnostic(const QString &text,
     );
 }
 
+const QString mainFileHeaderPath = QString::fromUtf8(TESTDATA_DIR "/someHeader.h");
 const QString mainFilePath = QString::fromUtf8(TESTDATA_DIR "/diagnostic_erroneous_source.cpp");
 const QString includedFilePath = QString::fromUtf8(TESTDATA_DIR "/diagnostic_erroneous_header.cpp");
 
@@ -91,6 +92,22 @@ DiagnosticContainer warningFromMainFile()
                 mainFilePath);
 }
 
+DiagnosticContainer pragmaOnceWarningInHeader()
+{
+    return createDiagnostic(
+                QStringLiteral("warning: #pragma once in main file"),
+                ClangBackEnd::DiagnosticSeverity::Warning,
+                mainFileHeaderPath);
+}
+
+DiagnosticContainer includeNextInPrimarySourceFileWarningInHeader()
+{
+    return createDiagnostic(
+                QStringLiteral("warning: #include_next in primary source file"),
+                ClangBackEnd::DiagnosticSeverity::Warning,
+                mainFileHeaderPath);
+}
+
 DiagnosticContainer errorFromMainFile()
 {
     return createDiagnostic(
@@ -193,6 +210,16 @@ TEST_F(ClangDiagnosticFilter, WarningsAreEmptyAfterTaking)
     ASSERT_TRUE(clangDiagnosticFilter.takeWarnings().isEmpty());
 }
 
+TEST_F(ClangDiagnosticFilter, IgnoreCertainWarningsInHeaderFiles)
+{
+    ClangCodeModel::Internal::ClangDiagnosticFilter myClangDiagnosticFilter{mainFileHeaderPath};
+
+    myClangDiagnosticFilter.filter({pragmaOnceWarningInHeader(),
+                                    includeNextInPrimarySourceFileWarningInHeader()});
+
+    ASSERT_TRUE(myClangDiagnosticFilter.takeWarnings().isEmpty());
+}
+
 TEST_F(ClangDiagnosticFilter, ErrorsAreEmptyAfterTaking)
 {
     clangDiagnosticFilter.filter({errorFromMainFile()});