Summary: We recently introduced a more precise model for constructing an optional from a value by making a shallow copy. However, this introduced Use After Delete false positives. For now, we go back to a less precise model by creating a fresh value. A proper model would be to either make a deep copy or call the copy constructor for a value. We will address this in the following diff.
Reviewed By: jvillard
Differential Revision: D24826749
fbshipit-source-id: 3e5e4edeb
Summary: `folly::Optional::value()` returns a reference, hence an error was shown when the actual value was being accessed. Since `value()` throws an exception in case of `folly::none`, we want to show the error message at the call site of `value()`. We do this by dereferencing the result of `value()` in the model.
Reviewed By: jvillard
Differential Revision: D24702875
fbshipit-source-id: ca9f30349
Summary:
Before we were creating a fresh internal value when we were constructing `folly::Optional`. This diff models `folly::Optional` constructor more precisely by copying the given value.
There was also a missing dereference in the model of `value_or`
Reviewed By: jvillard
Differential Revision: D24621016
fbshipit-source-id: c86d3c157
Summary: Model `folly::Optional::value_or(default)` to return value if not-empty and `default` if empty.
Reviewed By: jvillard
Differential Revision: D24539456
fbshipit-source-id: cc9e176cc
Summary:
We need to check if `folly::Optional` is not `folly::none` if we want to retrieve the value, otherwise a runtime exception is thrown:
```
folly::Optional<int> foo{folly::none};
return foo.value(); // bad
```
```
folly::Optional<int> foo{folly::none};
if (foo) {
return foo.value(); // ok
}
```
This diff adds a new issue type that reports if we try to access `folly::Optional` value when it is known to be `folly::none`.
Reviewed By: ezgicicek
Differential Revision: D22053352
fbshipit-source-id: 32cb00a99
Daiva Naudziuniene