Introduce signal-with-return-value

It's a design smell to have signals returning values

3 files changed, 103 insertions, 0 deletions

diff --git a/src/Checks.h b/src/Checks.h
index 00cb6b9c..a2df0180 100644
--- a/src/Checks.h
+++ b/src/Checks.h
@@ -42,6 +42,7 @@
 #include "checks/manuallevel/qvariant-template-instantiation.h"
 #include "checks/manuallevel/raw-environment-function.h"
 #include "checks/manuallevel/reserve-candidates.h"
+#include "checks/manuallevel/signal-with-return-value.h"
 #include "checks/manuallevel/thread-with-slots.h"
 #include "checks/manuallevel/tr-non-literal.h"
 #include "checks/manuallevel/unneeded-cast.h"
@@ -135,6 +136,7 @@ void CheckManager::registerChecks()
     registerCheck(check<QVariantTemplateInstantiation>("qvariant-template-instantiation", ManualCheckLevel,  RegisteredCheck::Option_VisitsStmts));
     registerCheck(check<RawEnvironmentFunction>("raw-environment-function", ManualCheckLevel,  RegisteredCheck::Option_VisitsStmts));
     registerCheck(check<ReserveCandidates>("reserve-candidates", ManualCheckLevel,  RegisteredCheck::Option_VisitsStmts));
+    registerCheck(check<SignalWithReturnValue>("signal-with-return-value", ManualCheckLevel,  RegisteredCheck::Option_VisitsDecls));
     registerCheck(check<ThreadWithSlots>("thread-with-slots", ManualCheckLevel,  RegisteredCheck::Option_VisitsStmts | RegisteredCheck::Option_VisitsDecls));
     registerCheck(check<TrNonLiteral>("tr-non-literal", ManualCheckLevel,  RegisteredCheck::Option_VisitsStmts));
     registerCheck(check<UnneededCast>("unneeded-cast", ManualCheckLevel,  RegisteredCheck::Option_VisitsStmts));
diff --git a/src/checks/manuallevel/signal-with-return-value.cpp b/src/checks/manuallevel/signal-with-return-value.cpp
new file mode 100644
index 00000000..25884374
--- /dev/null
+++ b/src/checks/manuallevel/signal-with-return-value.cpp
@@ -0,0 +1,61 @@
+/*
+  This file is part of the clazy static checker.
+
+  Copyright (C) 2019 Sergio Martins <smartins@kde.org>
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Library General Public
+  License as published by the Free Software Foundation; either
+  version 2 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Library General Public License for more details.
+
+  You should have received a copy of the GNU Library General Public License
+  along with this library; see the file COPYING.LIB.  If not, write to
+  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+  Boston, MA 02110-1301, USA.
+*/
+
+#include "signal-with-return-value.h"
+#include "Utils.h"
+#include "HierarchyUtils.h"
+#include "QtUtils.h"
+#include "TypeUtils.h"
+#include "AccessSpecifierManager.h"
+#include "ClazyContext.h"
+
+#include <clang/AST/AST.h>
+
+using namespace clang;
+using namespace std;
+
+
+SignalWithReturnValue::SignalWithReturnValue(const std::string &name, ClazyContext *context)
+    : CheckBase(name, context)
+{
+    context->enableAccessSpecifierManager();
+}
+
+void SignalWithReturnValue::VisitDecl(clang::Decl *decl)
+{
+    AccessSpecifierManager *accessSpecifierManager = m_context->accessSpecifierManager;
+    auto method = dyn_cast<CXXMethodDecl>(decl);
+    if (!accessSpecifierManager || !method)
+        return;
+
+    if (method->isThisDeclarationADefinition() && !method->hasInlineBody())
+        return;
+
+    const bool methodIsSignal = accessSpecifierManager->qtAccessSpecifierType(method) == QtAccessSpecifier_Signal;
+    if (!methodIsSignal)
+        return;
+
+    if (!method->getReturnType()->isVoidType()) {
+        if (!accessSpecifierManager->isScriptable(method)) {
+            emitWarning(decl, std::string(clazy::name(method)) + "() should return void. For a clean design signals shouldn't assume a single slot are connected to them.");
+        }
+    }
+}
diff --git a/src/checks/manuallevel/signal-with-return-value.h b/src/checks/manuallevel/signal-with-return-value.h
new file mode 100644
index 00000000..b94685e1
--- /dev/null
+++ b/src/checks/manuallevel/signal-with-return-value.h
@@ -0,0 +1,40 @@
+/*
+  This file is part of the clazy static checker.
+
+  Copyright (C) 2019 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com
+  Author: Sergio Martins <sergio.martins@kdab.com>
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Library General Public
+  License as published by the Free Software Foundation; either
+  version 2 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Library General Public License for more details.
+
+  You should have received a copy of the GNU Library General Public License
+  along with this library; see the file COPYING.LIB.  If not, write to
+  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+  Boston, MA 02110-1301, USA.
+*/
+
+#ifndef CLAZY_SIGNAL_WITH_RETURN_VALUE_H
+#define CLAZY_SIGNAL_WITH_RETURN_VALUE_H
+
+#include "checkbase.h"
+
+
+/**
+ * See README-signal-with-return-value.md for more info.
+ */
+class SignalWithReturnValue : public CheckBase
+{
+public:
+    explicit SignalWithReturnValue(const std::string &name, ClazyContext *context);
+    void VisitDecl(clang::Decl *) override;
+private:
+};
+
+#endif