Fixed #9795 (False positive: Local lock is not ineffective, mutex is locked in thread also.)

lib/checkstl.cpp

@@ -2394,25 +2394,12 @@ void CheckStl::useStlAlgorithm()
     }
 }
 
-static bool isMutex(const Variable* var)
-{
-    const Token* tok = Token::typeDecl(var->nameToken()).first;
-    return Token::Match(tok, "std :: mutex|recursive_mutex|timed_mutex|recursive_timed_mutex|shared_mutex");
-}
-
 static bool isLockGuard(const Variable* var)
 {
     const Token* tok = Token::typeDecl(var->nameToken()).first;
     return Token::Match(tok, "std :: lock_guard|unique_lock|scoped_lock");
 }
 
-static bool isLocalMutex(const Variable* var, const Scope* scope)
-{
-    if (!var)
-        return false;
-    return !var->isReference() && !var->isRValueReference() && !var->isStatic() && var->scope() == scope;
-}
-
 void CheckStl::globalLockGuardError(const Token* tok)
 {
     reportError(tok, Severity::warning,
@@ -2420,13 +2407,6 @@ void CheckStl::globalLockGuardError(const Token* tok)
                 "Lock guard is defined globally. Lock guards are intended to be local. A global lock guard could lead to a deadlock since it won't unlock until the end of the program.", CWE833, false);
 }
 
-void CheckStl::localMutexError(const Token* tok)
-{
-    reportError(tok, Severity::warning,
-                "localMutex",
-                "The lock is ineffective because the mutex is locked at the same scope as the mutex itself.", CWE667, false);
-}
-
 void CheckStl::checkMutexes()
 {
     for (const Scope *function : mTokenizer->getSymbolDatabase()->functionScopes) {
@@ -2434,19 +2414,12 @@ void CheckStl::checkMutexes()
             const Variable* var = tok->variable();
             if (!var)
                 continue;
-            if (Token::Match(tok, "%var% . lock ( )")) {
+            if (Token::Match(tok, "%var% (|{ %var% )|}|,")) {
-                if (!isMutex(var))
-                    continue;
-                if (isLocalMutex(var, tok->scope()))
-                    localMutexError(tok);
-            } else if (Token::Match(tok, "%var% (|{ %var% )|}|,")) {
                 if (!isLockGuard(var))
                     continue;
                 const Variable* mvar = tok->tokAt(2)->variable();
                 if (var->isStatic() || var->isGlobal())
                     globalLockGuardError(tok);
-                else if (isLocalMutex(mvar, tok->scope()))
-                    localMutexError(tok);
             }
         }
     }

lib/checkstl.h

@@ -233,7 +233,6 @@ private:
     void useStlAlgorithmError(const Token *tok, const std::string &algoName);
 
     void globalLockGuardError(const Token *tok);
-    void localMutexError(const Token *tok);
 
     void getErrorMessages(ErrorLogger* errorLogger, const Settings* settings) const OVERRIDE {
         ErrorPath errorPath;
@@ -272,7 +271,6 @@ private:
         c.readingEmptyStlContainerError(nullptr);
         c.useStlAlgorithmError(nullptr, "");
         c.globalLockGuardError(nullptr);
-        c.localMutexError(nullptr);
     }
 
     static std::string myName() {

test/teststl.cpp

@@ -4445,28 +4445,6 @@ private:
               true);
         ASSERT_EQUALS("", errout.str());
 
-        check("void f() {\n"
-              "    std::mutex m;\n"
-              "    std::lock_guard<std::mutex> g(m);\n"
-              "}\n",
-              true);
-        ASSERT_EQUALS("[test.cpp:3]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
-
-        check("void f() {\n"
-              "    std::mutex m;\n"
-              "    std::unique_lock<std::mutex> g(m);\n"
-              "}\n",
-              true);
-        ASSERT_EQUALS("[test.cpp:3]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
-
-        check("void f() {\n"
-              "    std::mutex m;\n"
-              "    std::unique_lock<std::mutex> g(m, std::defer_lock);\n"
-              "    std::lock(g);\n"
-              "}\n",
-              true);
-        ASSERT_EQUALS("[test.cpp:3]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
-
         check("void g();\n"
               "void f() {\n"
               "    static std::mutex m;\n"
@@ -4477,16 +4455,6 @@ private:
               true);
         ASSERT_EQUALS("", errout.str());
 
-        check("void g();\n"
-              "void f() {\n"
-              "    std::mutex m;\n"
-              "    m.lock();\n"
-              "    g();\n"
-              "    m.unlock();\n"
-              "}\n",
-              true);
-        ASSERT_EQUALS("[test.cpp:4]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
-
         check("class A {\n"
               "    std::mutex m;\n"
               "    void f() {\n"
@@ -4535,25 +4503,6 @@ private:
               "}\n",
               true);
         ASSERT_EQUALS("", errout.str());
-
-        check("std::mutex& h();\n"
-              "void f() {\n"
-              "    auto m = h();\n"
-              "    std::lock_guard<std::mutex> g(m);\n"
-              "}\n",
-              true);
-        ASSERT_EQUALS("[test.cpp:4]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
-
-        check("void g();\n"
-              "std::mutex& h();\n"
-              "void f() {\n"
-              "    auto m = h();\n"
-              "    m.lock();\n"
-              "    g();\n"
-              "    m.unlock();\n"
-              "}\n",
-              true);
-        ASSERT_EQUALS("[test.cpp:5]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
     }
 };