Fix #13797 FN nullPointer with negated if-condition (regression) (danmar#8172)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/checkunusedfunctions.cpp

@@ -385,7 +385,7 @@ bool CheckUnusedFunctions::check(const Settings& settings, ErrorLogger& errorLog
             if (func.filename != "+")
                 filename = func.filename;
             errors.emplace_back(filename, func.fileIndex, func.lineNumber, func.column, it->first);
-        } else if (func.isC && !func.isStatic && !func.usedOtherFile) {
+        } else if (func.isC && !func.isStatic) {
             std::string filename;
             if (func.filename != "+")
                 filename = func.filename;

lib/library.cpp

@@ -210,7 +210,7 @@ Library::Error Library::load(const char exename[], const char path[], bool debug
     tinyxml2::XMLError error = xml_LoadFile(doc, fullfilename.c_str());
     if (error == tinyxml2::XML_ERROR_FILE_NOT_FOUND) {
         // only perform further lookups when the given path was not absolute
-        if (!is_abs_path && error == tinyxml2::XML_ERROR_FILE_NOT_FOUND)
+        if (!is_abs_path)
         {
             std::list<std::string> cfgfolders;
     #ifdef FILESDIR

lib/symboldatabase.cpp

@@ -1023,7 +1023,7 @@ void SymbolDatabase::createSymbolDatabaseNeedInitialization()
                             if (var.isClass() && !var.isReference()) {
                                 if (var.type()) {
                                     // does this type need initialization?
-                                    if (var.type()->needInitialization == Type::NeedInitialization::True && !var.hasDefault() && !var.isStatic())
+                                    if (var.type()->needInitialization == Type::NeedInitialization::True && !var.hasDefault())
                                         needInitialization = true;
                                     else if (var.type()->needInitialization == Type::NeedInitialization::Unknown) {
                                         if (!(var.valueType() && var.valueType()->type == ValueType::CONTAINER))

lib/vf_analyzers.cpp

@@ -139,7 +139,7 @@ struct ValueFlowAnalyzer : Analyzer {
                 return result;
             }
             ConditionState lhs = analyzeCondition(tok->astOperand1(), depth - 1);
-            if (lhs.isUnknownDependent())
+            if (lhs.isUnknownDependent() || !tok->astOperand2())
                 return lhs;
             ConditionState rhs = analyzeCondition(tok->astOperand2(), depth - 1);
             if (rhs.isUnknownDependent())
@@ -1202,7 +1202,7 @@ struct SingleValueFlowAnalyzer : ValueFlowAnalyzer {
             return false;
         if (value.isImpossible())
             return false;
-        if (isConditional() && !value.isKnown() && !value.isImpossible())
+        if (isConditional() && !value.isKnown())
             return true;
         if (value.isSymbolicValue())
             return false;

test/testnullpointer.cpp

@@ -2458,6 +2458,14 @@ class TestNullPointer : public TestFixture {
               "    if (h(i) && *i == 1) {}\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("void f(int i) {\n" // #13797
+              "    int* p = nullptr;\n"
+              "    if (!i) {\n"
+              "        *p = 0;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4:10]: (error) Null pointer dereference: p [nullPointer]\n", errout_str());
     }
 
     void nullpointer78() // #7802
@@ -3929,7 +3937,8 @@ class TestNullPointer : public TestFixture {
               "  std::string s(p);\n"
               "  return s;\n"
               "}\n", dinit(CheckOptions, $.inconclusive = true));
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:6:17]: (warning, inconclusive) Possible null pointer dereference: p [nullPointer]\n",
+                      errout_str());
 
         check("void f() {\n" // #11078
               "    const char* p = nullptr;\n"