Quoting commits:

This test shows that `array_map([new TraceableMessageBus(...), 'dispatch'], $messages)` does not work at all,because `debug_backtrace()` is used in internals to compute the call-site, and it is not considering the factthat the caller may be: * an internal PHP function * a callback (this example test scenario) * generated code (`eval()` result)The output of such a failure:```1) Symfony\Component\Messenger\Tests\TraceableMessageBusTest::testItTracesExceptionsWhenMessageBusIsFiredFromArrayCallbackUndefined array key "line"/app/src/Symfony/Component/Messenger/TraceableMessageBus.php:66/app/src/Symfony/Component/Messenger/TraceableMessageBus.php:36/app/src/Symfony/Component/Messenger/Tests/TraceableMessageBusTest.php:175```To be on the safe side, also removed `compact()` usage, which was making everythingmuch muddier and harder to comprehend.