All the previous refactoring to make the assertion fast paths
smaller and faster also allows us to implement the fast paths
just with thread-local and atomic variables, without full mutexes.
However, the performance overhead of thread-safe assertions is
still significant for single threaded usage:
| slowdown | Debug | Release |
|-----------|--------:|--------:|
| fast path | 1.04x | 1.43x |
| slow path | 1.16x | 1.22x |
Thus, we don't make the assertions thread-safe by default, and instead
provide a build-time configuration option that the users can set to get
thread-safe assertions.
This commit is functional, but it still needs some follow-up work:
* We do not need full seq_cst increments for the atomic counters,
and using weaker ones can be faster.
* We brute-force updating the reporter-friendly totals from internal
atomic counters by doing it everywhere. We should properly trace
where this is needed instead.
* Message macros (`INFO`, `UNSCOPED_INFO`, `CAPTURE`, etc) are not
made thread safe in this commit, but they can be made thread safe
in the future, by building on top of this work.
* Add more tests, including with thread-sanitizer, and compiled
examples to the repository. Right now, these changes have been
compiled with tsan manually, but these tests are not added to CI.
Closes#2948
This means that:
1) Scoped messages are always removed at the end of their scope,
even if the scope ended due to an exception.
2) Scoped messages outlive section end, if that section's scope is
enclosed in their own.
Previously neither of these were true, which has led to a number
of surprising behaviour, where e.g. this:
```cpp
TEST_CASE() {
try {
INFO( "some info" );
throw std::runtime_error( "ex" );
} catch (std::exception const&) {}
REQUIRE( false );
}
```
would print "some info" as the message for the assertion, while this:
```cpp
TEST_CASE() {
INFO("Hello");
SECTION("dummy") {}
REQUIRE(false);
}
```
would not print out "Hello" as the message for the assertion.
This had an underlying reason, in that it was trying to helpfully
keep the messages around in case of unexpected exceptions, so that
code like this:
```cpp
TEST_CASE() {
auto [input, expected] = GENERATE(...);
CAPTURE(input);
auto result = transform(input); // throws
REQUIRE(result == expected);
}
```
would report the value of `input` when `transform` throws. However,
it was surprising in practice and was causing various issues around
handling of messages in other cases.
Closes#1759Closes#2019Closes#2959
We still want to build VS 2017 through AppVeyor, and those images
have CMake 3.16.2 installed. We could install newer CMake as part
of the build, but since we don't use newer CMake features yet, this
is simpler.
Turns out that even in GCC, the expression in `__builtin_cosntant_p`
can end up evaluated and side-effects executed. To allow users to
work around this bug, I added a configuration option to disable its
use in internal macros.
Related to #2925
This PR introduces a new `TEST_CASE` macro called `TEST_CASE_PERSISTENT_FIXTURE`. `TEST_CASE_PERSISTENT_FIXTURE` offers the same functionality as `TEST_CASE_METHOD` except for one difference. The object on which the test method is invoked is only created once for all invocations of the test case. The object is created just after the `testCaseStarting` event is broadcast and the object is destroyed just before the `testCaseEnding` event is broadcast.
The main motivation for this new functionality is to allow `TEST_CASE`s to do expensive setup and teardown once per `TEST_CASE`, without having to resort to abusing event listeners or static function variables with manual initialization.
Implements #1602
---------
Co-authored-by: Martin Hořeňovský <martin.horenovsky@gmail.com>
