False positive: redundantIfRemove when conditional code has extra code

[Daniel Marjamäki]

Example code:

#include <set>
#include <string>

void unsubscribe(const std::string& key);

std::set<std::string> g_params;

void del(const std::string& key) {
    if (g_params.find(key) != g_params.end()) {
        g_params.erase(key);
        unsubscribe(key); // only call if key was present
    }
}

Command:

cppcheck --enable=style fp.cpp

False positive:

fp.cpp:9:9: style: Redundant checking of STL container element existence before removing it. [redundantIfRemove]
    if (g_params.find(key) != g_params.end()) {
        ^

Without a check, the unsubscribe function would always be called.

[chrchr]

Also, the only test case we have is based on a non-existent string::remove() method.

E.g. QSet has remove(), but currently there is no validation of the container.

[kidkat]

This started with 1.65 and has been bisected to ​https://github.com/cppcheck-opensource/cppcheck/commit/776ad32a0b832758eb1520289a791b206d28bdf9.

[chrchr]

Fixed by ​https://github.com/cppcheck-opensource/cppcheck/pull/8789