false positive in cppcheck 2.0

[Cristian Del Fabbro]

Hi,
I found a false positive in cppcheck 2.0 (previous versions are fine) in the following code:

#include <iostream>

void do_something(const char ** test) {
    *test = "test";
}

bool test(int a) {
    bool ok = false;
    const char * r = nullptr;

    do_something(&r);

    if (r != nullptr) {
        ok = a != 0;
    }

    if (ok) {
        std::cout << "TRUE" << std::endl;
    } else {
        std::cout << "FALSE" << std::endl;
    }
    return ok;
}


int main() {
    int c;
    std::cin >> c;
    test(c);
    return 0;
}

The cppcheck output is:

cdf@work:~/tmp/$ cppcheck test.cpp --enable=all --std=c++14        

Checking test.cpp ...
test.cpp:19:6: style: Condition 'ok' is always false [knownConditionTrueFalse]
 if (ok) {
     ^
test.cpp:9:12: note: Assignment 'ok=false', assigned value is 0
 bool ok = false;
           ^
test.cpp:19:6: note: Condition 'ok' is always false
 if (ok) {
     ^
nofile:0:0: information: Cppcheck cannot find all the include files (use --check-config for details) [missingIncludeSystem]

But the variable ok can be true or false:

cdf@work:~/tmp/$ g++ test.cpp -o test
cdf@work:~/tmp/$ ./test 
0
FALSE
cdf@work:~/tmp/$ ./test 
1
TRUE
cdf@work:~/tmp/$ 

[Daniel Marjamäki]

Thanks! I created this trac ticket: https://trac.cppcheck.net/ticket/9709

[Daniel Marjamäki]

For information, the bug is in the data flow analysis.

[Cristian Del Fabbro]

Thanks!!!