Fix #12083 FN passedByValue with usage in ternary (#5575)

lib/checkother.cpp

@@ -1227,104 +1227,6 @@ static int estimateSize(const Type* type, const Settings* settings, const Symbol
     });
 }
 
-static bool isConstRangeBasedFor(const Token* tok) {
-    if (astIsRangeBasedForDecl(tok)) {
-        const Variable* loopVar = tok->astParent()->astOperand1()->variable();
-        return loopVar && (!loopVar->isReference() || loopVar->isConst());
-    }
-    return false;
-}
-
-static bool canBeConst(const Variable *var, const Settings* settings)
-{
-    if (!var->scope())
-        return false;
-    {
-        // check initializer list. If variable is moved from it can't be const.
-        const Function* func_scope = var->scope()->function;
-        if (func_scope && func_scope->type == Function::Type::eConstructor) {
-            //could be initialized in initializer list
-            const Token* init = func_scope->arg->link()->next();
-            if (init->str() == "noexcept") {
-                init = init->next();
-                if (init->link())
-                    init = init->link()->next();
-            }
-            if (init->str() == ":") {
-                for (const Token* tok2 = func_scope->arg->link()->next()->next(); tok2 != var->scope()->bodyStart; tok2 = tok2->next()) {
-                    if (tok2->varId() != var->declarationId())
-                        continue;
-                    const Token* parent = tok2->astParent();
-                    if (parent && Token::simpleMatch(parent->previous(), "move ("))
-                        return false;
-                }
-            }
-        }
-    }
-    for (const Token* tok2 = var->scope()->bodyStart; tok2 != var->scope()->bodyEnd; tok2 = tok2->next()) {
-        if (tok2->varId() != var->declarationId())
-            continue;
-
-        const Token* parent = tok2->astParent();
-        while (Token::simpleMatch(parent, "["))
-            parent = parent->astParent();
-        if (!parent)
-            continue;
-        if (Token::simpleMatch(tok2->next(), ";") && tok2->next()->isSplittedVarDeclEq()) {
-            tok2 = tok2->tokAt(2);
-            tok2 = Token::findsimplematch(tok2, ";");
-            continue;
-        }
-        if (parent->str() == "<<" || isLikelyStreamRead(true, parent)) {
-            if (parent->str() == "<<" && parent->astOperand1() == tok2)
-                return false;
-            if (parent->str() == ">>" && parent->astOperand2() == tok2)
-                return false;
-        } else if (parent->str() == "," || parent->str() == "(") { // function argument
-            int argNr = -1;
-            const Token* functionTok = getTokenArgumentFunction(tok2, argNr);
-            if (!functionTok)
-                return false;
-            const Function* tokFunction = functionTok->function();
-            if (tokFunction) {
-                const Variable* argVar = tokFunction->getArgumentVar(argNr);
-                if (!argVar || (!argVar->isConst() && argVar->isReference()))
-                    return false;
-            }
-            else if (!settings->library.isFunctionConst(functionTok))
-                return false;
-        } else if (parent->isUnaryOp("&")) {
-            // TODO: check how pointer is used
-            return false;
-        } else if (parent->isConstOp() ||
-                   (parent->astOperand2() && settings->library.isFunctionConst(parent->astOperand2())))
-            continue;
-        else if (parent->isAssignmentOp()) {
-            const Token* assignee = parent->astOperand1();
-            while (Token::simpleMatch(assignee, "["))
-                assignee = assignee->astOperand1();
-            if (assignee == tok2)
-                return false;
-            const Variable* assignedVar = assignee ? assignee->variable() : nullptr;
-            if (assignedVar &&
-                !assignedVar->isConst() &&
-                assignedVar->isReference() &&
-                assignedVar->nameToken() == parent->astOperand1())
-                return false;
-        } else if (Token::Match(tok2, "%var% . %name% (")) {
-            const Function* func = tok2->tokAt(2)->function();
-            if (func && (func->isConst() || func->isStatic()))
-                continue;
-            return false;
-        } else if (isConstRangeBasedFor(tok2))
-            continue;
-        else
-            return false;
-    }
-
-    return true;
-}
-
 void CheckOther::checkPassByReference()
 {
     if (!mSettings->severity.isEnabled(Severity::performance) || mTokenizer->isC())
@@ -1374,7 +1276,7 @@ void CheckOther::checkPassByReference()
         if (!var->scope() || var->scope()->function->isImplicitlyVirtual())
             continue;
 
-        if (canBeConst(var, mSettings)) {
+        if (!isVariableChanged(var, mSettings, mTokenizer->isCPP())) {
             passedByValueError(var, inconclusive);
         }
     }
@@ -2939,7 +2841,9 @@ void CheckOther::checkRedundantCopy()
     const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
 
     for (const Variable* var : symbolDatabase->variableList()) {
-        if (!var || var->isReference() || (!var->isConst() && !canBeConst(var, mSettings)) || var->isPointer() || (!var->type() && !var->isStlType())) // bailout if var is of standard type, if it is a pointer or non-const
+        if (!var || var->isReference() || var->isPointer() ||
+            (!var->type() && !var->isStlType()) || // bailout if var is of standard type, if it is a pointer or non-const
+            (!var->isConst() && isVariableChanged(var, mSettings, mTokenizer->isCPP())))
             continue;
 
         const Token* startTok = var->nameToken();

lib/path.cpp

@@ -284,7 +284,7 @@ bool Path::isDirectory(const std::string &path)
     return file_type(path) == S_IFDIR;
 }
 
-std::string Path::join(std::string path1, std::string path2) {
+std::string Path::join(const std::string& path1, const std::string& path2) {
     if (path1.empty() || path2.empty())
         return path1 + path2;
     if (path2.front() == '/')

lib/path.h

@@ -197,7 +197,7 @@ public:
     /**
      * join 2 paths with '/' separators
      */
-    static std::string join(std::string path1, std::string path2);
+    static std::string join(const std::string& path1, const std::string& path2);
 };
 
 /// @}

test/cfg/std.cpp

@@ -4497,7 +4497,7 @@ void getline()
     in.close();
 }
 
-// TODO cppcheck-suppress passedByValue
+// cppcheck-suppress passedByValue
 void stream_write(std::ofstream& s, std::vector<char> v) {
     if (v.empty()) {}
     s.write(v.data(), v.size());

test/testother.cpp

@@ -2167,6 +2167,11 @@ private:
               "}\n");
         ASSERT_EQUALS("[test.cpp:4]: (performance) Function parameter 'v' should be passed by const reference.\n", errout.str());
 
+        check("void f(const std::string& s, std::string t) {\n" // #12083
+              "    const std::string& v = !s.empty() ? s : t;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:1]: (performance) Function parameter 't' should be passed by const reference.\n", errout.str());
+
         Settings settings1 = settingsBuilder().platform(Platform::Type::Win64).build();
         check("using ui64 = unsigned __int64;\n"
               "ui64 Test(ui64 one, ui64 two) { return one + two; }\n",
@@ -2201,7 +2206,9 @@ private:
         check("void f(std::string str) {\n"
               "    std::string& s2 = str;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Variable 's2' can be declared as reference to const\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:1]: (performance) Function parameter 'str' should be passed by const reference.\n"
+                      "[test.cpp:2]: (style) Variable 's2' can be declared as reference to const\n",
+                      errout.str());
 
         check("void f(std::string str) {\n"
               "    const std::string& s2 = str;\n"
@@ -2354,7 +2361,9 @@ private:
               "    int& i = x[0];\n"
               "    return i;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Variable 'i' can be declared as reference to const\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:1]: (performance) Function parameter 'x' should be passed by const reference.\n"
+                      "[test.cpp:2]: (style) Variable 'i' can be declared as reference to const\n",
+                      errout.str());
 
         check("int f(std::vector<int>& x) {\n"
               "    return x[0];\n"
@@ -2371,7 +2380,7 @@ private:
               "    static int& i = x[0];\n"
               "    return i;\n"
               "}");
-        ASSERT_EQUALS("", errout.str());
+        ASSERT_EQUALS("[test.cpp:1]: (performance) Function parameter 'x' should be passed by const reference.\n", errout.str());
 
         check("int f(std::vector<int> x) {\n"
               "    int& i = x[0];\n"