MatcherBase::match() runs before EventListenerBase::assertionStarting()

[vberlier]

Describe the bug
The docs say that assertionStarting is called after the expression is captured, but before the assertion expression is evaluated. For custom matchers the match member function is in charge of evaluating the assertion expression, but by the time the assertionStarting event is dispatched match has already been invoked.

Expected behavior
assertionStarting should run before custom matchers.

Reproduction steps

class DummyCatchListener : public Catch::EventListenerBase {
public:
    using Catch::EventListenerBase::EventListenerBase;

    void assertionStarting(Catch::AssertionInfo const& assertionInfo) override {
        std::cout << assertionInfo.lineInfo.file << ":" << assertionInfo.lineInfo.line << std::endl;
    }
};

CATCH_REGISTER_LISTENER(DummyCatchListener)

class DummyMatcher : public Catch::Matchers::MatcherBase<int> {
public:
    bool match(int const& in) const override {
        std::cout << "match " << in << std::endl;
        return true;
    }
};

TEST_CASE("Dummy") {
    CHECK_THAT(123, DummyMatcher{});
}

match 123
path/to/dummy_test.cpp:42

Additional context
I'm trying to use a listener to update global variables to be able to access the current assertion file and line in a custom matcher. If there's another way to do it let me know :)

[horenmar]

That's definitely not the intended behaviour, I'll have to check how hard it will be to fix.

[horenmar]

Okay, so it might be a larger surgery. The basic assertions currently behave in the same way, and I would have to ensure that the proper information is wired around before the expression is evaluated.

[vberlier]

Thanks for the fix! Have a good day :)