walkero
/
cppcheck
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

Partial fix for 11303: False negative: knownConditionTrueFalse using container .back() (#4633) 

* Partial fix for 11303: False negative: knownConditionTrueFalse using container .back()

* Format

* Fix error message
This commit is contained in:
Paul Fultz II 2022-12-15 11:35:19 -06:00 committed by GitHub
parent 90898945c1
commit 9c55b933c1
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 40 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
lib/astutils.cpp
View File

@ -2472,6 +2472,37 @@ bool isVariableChanged(const Token *tok, int indirect, const Settings *settings,
return false;
const Token *ftok = tok->tokAt(2);
if (astIsContainer(tok) && tok->valueType() && tok->valueType()->container) {
const Library::Container* c = tok->valueType()->container;
const Library::Container::Action action = c->getAction(ftok->str());
if (contains({Library::Container::Action::INSERT,
Library::Container::Action::ERASE,
Library::Container::Action::CHANGE,
Library::Container::Action::CHANGE_CONTENT,
Library::Container::Action::CHANGE_INTERNAL,
Library::Container::Action::CLEAR,
Library::Container::Action::PUSH,
Library::Container::Action::POP,
Library::Container::Action::RESIZE},
action))
return true;
const Library::Container::Yield yield = c->getYield(ftok->str());
// If accessing element check if the element is changed
if (contains({Library::Container::Yield::ITEM, Library::Container::Yield::AT_INDEX}, yield)) {
return isVariableChanged(ftok->next(), indirect, settings, cpp, depth - 1);
} else if (contains({Library::Container::Yield::BUFFER,
Library::Container::Yield::BUFFER_NT,
Library::Container::Yield::START_ITERATOR,
Library::Container::Yield::ITERATOR},
yield)) {
return isVariableChanged(ftok->next(), indirect + 1, settings, cpp, depth - 1);
} else if (contains({Library::Container::Yield::SIZE,
Library::Container::Yield::EMPTY,
Library::Container::Yield::END_ITERATOR},
yield)) {
return false;
}
}
if (settings)
return !settings->library.isFunctionConst(ftok);

9
test/testcondition.cpp
View File

@ -4910,6 +4910,15 @@ private:
" return *it;\n"
"}\n");
ASSERT_EQUALS("[test.cpp:4]: (style) Condition 'it!=vector.end()' is always true\n", errout.str());
// #11303
check("void f(int n) {\n"
" std::vector<char> buffer(n);\n"
" if(buffer.back() == 0 ||\n"
" buffer.back() == '\\n' ||\n"
" buffer.back() == '\\0') {}\n"
"}\n");
ASSERT_EQUALS("[test.cpp:5]: (style) Condition 'buffer.back()=='\\0'' is always false\n", errout.str());
}
void alwaysTrueLoop()