| Issue |
174250
|
| Summary |
[clang-tidy]: `bugprone-unchecked-optional-access` false-positive if inside a loop we use checked optional value (might be a regression of CFG)
|
| Labels |
clang-tidy,
false-positive
|
| Assignees |
|
| Reporter |
BaLiKfromUA
|
## Way to reproduce
Smallest example which me and my colleague managed to make:
```cpp
#include <optional>
#include <vector>
std::vector<std::optional<int>> getOptionals();
void test() {
for (const auto &opt : getOptionals()) {
if (opt.has_value()) {
int x = opt.value(); // NO ERROR
}
}
std::optional<int> opt;
if (opt.has_value()) {
for (int i = 0; i < 10; ++i) {
int x = opt.value(); // NO ERROR
}
}
for (const auto &opt : getOptionals()) {
if (opt.has_value()) {
for (int i = 0; i < 10; ++i) {
int x = opt.value(); // ERROR
}
}
}
// Also happens when the loop is unbounded
for (const auto &opt : getOptionals()) {
if (opt.has_value()) {
for (;;) {
int x = opt.value(); // ERROR
}
}
}
}
```
[Compiler Explorer Link](https://compiler-explorer.com/z/9e6zjor5T)
## Initial problem / User Impact
After fixing https://github.com/llvm/llvm-project/pull/168863 I found new false-positive like:
```cpp
bsl::vector<bsl::optional<bsl::string>> getOptionals();
void test_with_ball_log_and_loop() {
BALL_LOG_SET_CATEGORY(__func__);
for (const auto& opt : getOptionals()) {
if (opt.has_value()) {
BALL_LOG_INFO << opt.value(); // ERROR?!
}
}
}
```
`BALL_LOG` is BDE tooling used for logging. [Link](https://bloomberg.github.io/bde-resources/doxygen/bde_api_prod/group__ball__log.html)
After some experiments, I found out that I can reproduce the same issue with `std::optional<int>` so it was somehow connected with `BALL_LOG`.
[Compiler Explorer Link](https://compiler-explorer.com/z/vdTvqrdv1).
Removing/expanding macros and includes resulted in example from the beginning :)
---
**So even though the initial example might be niche, the original issue is pretty common pattern reported by users.**
JFYI, I cannot reproduce it with clang-18 and clang-19 releases but I can reproduce it with clang-20 and clang-21. So maybe it's a regression??
![]()
_______________________________________________
llvm-bugs mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
