Uninitialized variables: Fixed false positives caused by recent commit when potentially uninitialized variable is read in condition

lib/checkuninitvar.cpp

@@ -1113,17 +1113,9 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const unsigned int
 
         // Inner scope..
         if (Token::Match(tok, "if (")) {
-            // initialization in condition..
+            // initialization / usage in condition..
-            const Token * const endToken = tok->next()->link();
+            if (checkIfForWhileHead(tok->next(), varid, ispointer, suppressErrors))
-            for (const Token *tok2 = tok->tokAt(2); tok2 != endToken; tok2 = tok2->next()) {
+                return true;
-                if (tok2->varId() == varid) {
-                    if (!suppressErrors && isVariableUsage(tok2, ispointer))
-                        uninitvarError(tok2, tok2->str());
-                    return true;
-                }
-                if (Token::Match(tok2, "sizeof|decltype|offsetof ("))
-                    tok2 = tok2->next()->link();
-            }
 
             // goto the {
             tok = tok->next()->link()->next();
@@ -1180,8 +1172,25 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const unsigned int
         if (Token::Match(tok, "sizeof|offsetof|decltype ("))
             tok = tok->next()->link();
 
+        // for..
+        if (Token::simpleMatch(tok, "for (")) {
+            // goto the {
+            const Token *tok2 = tok->next()->link()->next();
+
+            bool possibleinit = true;
+            bool init = checkScopeForVariable(tok2->next(), varid, ispointer, &possibleinit);
+
+            // variable is initialized in the loop..
+            if (possibleinit || init)
+                return true;
+
+            // is variable used / initialized in for-head
+            if (checkIfForWhileHead(tok->next(), varid, ispointer, suppressErrors))
+                return true;
+        }
+
         // TODO: handle loops, try, etc
-        if (tok->str() == "for" || Token::simpleMatch(tok, ") {") || Token::Match(tok, "%var% {")) {
+        if (Token::simpleMatch(tok, ") {") || Token::Match(tok, "%var% {")) {
             return true;
         }
 
@@ -1210,6 +1219,23 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const unsigned int
     return ret;
 }
 
+bool CheckUninitVar::checkIfForWhileHead(const Token *startparanthesis, unsigned int varid, bool ispointer, bool suppressErrors)
+{
+    const Token * const endpar = startparanthesis->link();
+    for (const Token *tok = startparanthesis->next(); tok && tok != endpar; tok = tok->next()) {
+        if (tok->varId() == varid) {
+            if (!suppressErrors && isVariableUsage(tok, ispointer))
+                uninitvarError(tok, tok->str());
+            return true;
+        }
+        if (Token::Match(tok, "sizeof|decltype|offsetof ("))
+            tok = tok->next()->link();
+        if (tok->str() == "&&")
+            suppressErrors = true;
+    }
+    return false;
+}
+
 bool CheckUninitVar::isVariableUsage(const Token *vartok, bool pointer) const
 {
     if (vartok->previous()->str() == "return")

lib/checkuninitvar.h

@@ -61,8 +61,10 @@ public:
     /** Check for uninitialized variables */
     void check();
     bool checkScopeForVariable(const Token *tok, const unsigned int varid, bool ispointer, bool * const possibleInit);
+    bool checkIfForWhileHead(const Token *startparanthesis, unsigned int varid, bool ispointer, bool suppressErrors);
     bool isVariableUsage(const Token *vartok, bool ispointer) const;
 
+
     /**
      * @brief Uninitialized variables: analyse functions to see how they work with uninitialized variables
      * @param tokens [in] the token list

test/testuninitvar.cpp

@@ -1863,7 +1863,7 @@ private:
                         "    for (int i = 0; i < 10; i += x) {\n"
                         "    }\n"
                         "}\n");
-        TODO_ASSERT_EQUALS("error", "", errout.str());
+        ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: x\n", errout.str());
 
         // try
         checkUninitVar2("void f() {\n"
@@ -1917,6 +1917,19 @@ private:
                         "}\n");
         ASSERT_EQUALS("", errout.str());
 
+        checkUninitVar2("static void f(int x, int y) {\n"
+                        "    int a;\n"
+                        "    if (x == 0) { a = y; }\n"
+                        "    if (x == 0 && (a == 1)) { }\n"
+                        "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        checkUninitVar2("static void f(int x, int y) {\n"
+                        "    int a;\n"
+                        "    if (x == 0 && (a == 1)) { }\n"
+                        "}\n");
+        TODO_ASSERT_EQUALS("error", "", errout.str());
+
         // asm
         checkUninitVar2("void f() {\n"
                         "    int x;\n"