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Fixed #9680 (false positive: style: Variable 'x' is assigned a value that is never used with smart pointers)

This commit is contained in:
Daniel Marjamäki 2020-09-27 19:15:15 +02:00
parent 65ac94aa88
commit ba84303501
2 changed files with 83 additions and 31 deletions
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81
lib/checkunusedvar.cpp
View File

@ -45,6 +45,53 @@ namespace {
static const struct CWE CWE563(563U); // Assignment to Variable without Use ('Unused Variable')
static const struct CWE CWE665(665U); // Improper Initialization
/** Is scope a raii class scope */
static bool isRaiiClassScope(const Scope *classScope)
{
return classScope && classScope->getDestructor() != nullptr;
}
/** Is ValueType a raii class? */
static bool isRaiiClass(const ValueType *valueType, bool cpp, bool defaultReturn = true)
{
if (!cpp)
return false;
if (!valueType)
return defaultReturn;
if (valueType->smartPointerType && isRaiiClassScope(valueType->smartPointerType->classScope))
return true;
switch (valueType->type) {
case ValueType::Type::UNKNOWN_TYPE:
case ValueType::Type::NONSTD:
return defaultReturn;
case ValueType::Type::RECORD:
if (isRaiiClassScope(valueType->typeScope))
return true;
return defaultReturn;
case ValueType::Type::CONTAINER:
case ValueType::Type::ITERATOR:
case ValueType::Type::VOID:
case ValueType::Type::BOOL:
case ValueType::Type::CHAR:
case ValueType::Type::SHORT:
case ValueType::Type::WCHAR_T:
case ValueType::Type::INT:
case ValueType::Type::LONG:
case ValueType::Type::LONGLONG:
case ValueType::Type::UNKNOWN_INT:
case ValueType::Type::FLOAT:
case ValueType::Type::DOUBLE:
case ValueType::Type::LONGDOUBLE:
return false;
}
return defaultReturn;
}
/**
* @brief This class is used create a list of variables within a function.
@ -1136,38 +1183,12 @@ void CheckUnusedVar::checkFunctionVariableUsage()
if (isIncrementOrDecrement && tok->astParent() && precedes(tok, tok->astOperand1()))
continue;
if (tok->str() == "=" && isRaiiClass(tok->valueType(), mTokenizer->isCPP(), false))
continue;
if (tok->isName()) {
if (mTokenizer->isCPP()) {
// do not check RAII/scope_lock objects
if (!tok->valueType())
if (isRaiiClass(tok->valueType(), mTokenizer->isCPP(), true))
continue;
bool check = false;
switch (tok->valueType()->type) {
case ValueType::Type::UNKNOWN_TYPE:
case ValueType::Type::NONSTD:
case ValueType::Type::RECORD:
check = tok->valueType()->typeScope && !tok->valueType()->typeScope->getDestructor();
break;
case ValueType::Type::CONTAINER:
case ValueType::Type::ITERATOR:
case ValueType::Type::VOID:
case ValueType::Type::BOOL:
case ValueType::Type::CHAR:
case ValueType::Type::SHORT:
case ValueType::Type::WCHAR_T:
case ValueType::Type::INT:
case ValueType::Type::LONG:
case ValueType::Type::LONGLONG:
case ValueType::Type::UNKNOWN_INT:
case ValueType::Type::FLOAT:
case ValueType::Type::DOUBLE:
case ValueType::Type::LONGDOUBLE:
check = true;
break;
}
if (!check)
continue;
}
tok = tok->next();
}
if (tok->astParent() && tok->str() != "(") {

31
test/testunusedvar.cpp
View File

@ -159,6 +159,7 @@ private:
TEST_CASE(localVarStd);
TEST_CASE(localVarClass);
TEST_CASE(localVarSmartPtr);
// Don't give false positives for variables in structs/unions
TEST_CASE(localvarStruct1);
@ -4433,6 +4434,36 @@ private:
ASSERT_EQUALS("", errout.str());
}
void localVarSmartPtr() {
// handling of smart pointers (#9680)
functionVariableUsage("static int s_i = 0;\n"
"\n"
"class A {\n"
"public:\n"
" ~A() {\n"
" ++s_i;\n"
" }\n"
"};\n"
"\n"
"static void func() {\n"
" auto a = std::make_shared<A>();\n"
" auto a2 = std::unique_ptr<A>(new A());\n"
"}\n");
ASSERT_EQUALS("", errout.str());
functionVariableUsage("class A {\n"
"public:\n"
" std::string x;\n"
"};\n"
"\n"
"static void func() {\n"
" auto a = std::make_shared<A>();\n"
" auto a2 = std::unique_ptr<A>(new A());\n"
"}\n");
ASSERT_EQUALS("[test.cpp:7]: (style) Variable 'a' is assigned a value that is never used.\n"
"[test.cpp:8]: (style) Variable 'a2' is assigned a value that is never used.\n", errout.str());
}
// ticket #3104 - false positive when variable is read with "if (NOT var)"
void localvarIfNOT() {
functionVariableUsage("void f() {\n"