Don't use die() but echo to skip tests.

[staabm]

To unlock PHPUnit side-effect-free in-process --SKIPIF-- evaluation, we use regular echo instead of die().
That way PHPunit can detect whether conditions may be evaluated in the main-process to reduce sub-process creation overhead.

Depends on the work-inprogress of sebastianbergmann/phpunit#5974

---

Running phpunit with the side-effect detecting PR vs. the regular master version, yields the following results in this PR on my windows laptop:

$ hyperfine '/c/tools/php83/php ../phpunit/phpunit tests' '/c/tools/php83/php vendor/bin/phpunit tests' --warmup=3
Benchmark 1: C:/tools/php83/php ../phpunit/phpunit tests
  Time (mean ± σ):      3.312 s ±  0.020 s    [User: 0.184 s, System: 0.510 s]
  Range (min … max):    3.291 s …  3.347 s    10 runs

Benchmark 2: C:/tools/php83/php vendor/bin/phpunit tests
  Time (mean ± σ):      3.555 s ±  0.031 s    [User: 0.220 s, System: 0.599 s]
  Range (min … max):    3.521 s …  3.604 s    10 runs

Summary
  C:/tools/php83/php ../phpunit/phpunit tests ran
    1.07 ± 0.01 times faster than C:/tools/php83/php vendor/bin/phpunit tests

$ /c/tools/php83/php -v
PHP 8.3.11 (cli) (built: Aug 27 2024 21:28:35) (NTS Visual C++ 2019 x64)
Copyright (c) The PHP Group
Zend Engine v4.3.11, Copyright (c) Zend Technologies

-> inline-skip-if evaluation of 7 test-cases - as proposed with this PR - will yield a 7-8% perf improvement.

[jrfnl]

Out of curiousity: how does PHPUnit decide whether the test should be skipped or not ?
I thought that was related to the exit code of the script run in the SKIPIF process ?

If that's no longer the case, the criteria for how the test skipping is determined in phpt tests need to be clearly outlined and documented.

[staabm]

Out of curiousity: how does PHPUnit decide whether the test should be skipped or not ?
I thought that was related to the exit code of the script run in the SKIPIF process ?

in the current stable PHPUnit release a test is skipped, when the executed code of the SKIPIF section output starts-with the string skip
see https://github.com/sebastianbergmann/phpunit/blob/a82cc054802a11b786f3159030a93d106335cb4d/src/Runner/PHPT/PhptTestCase.php#L420-L451

this works for e.g. die("skip because something happened") - because die prints the result on stdout or also regular echo "skip because something happened".

---

the indicator, when a test will be skipped, does not change with my proposed PR.
only difference between echo and die is, that we can evaluate code - which does not exit/die the current process or does not pollute the main-process scope (e.g. by defining classes/functions/symbols) - in the phpunit main process - and thats the reason why I propose this changes here.

In the PHPUnit PR I am using staabm/side-effects-detector to inspect the code in the SKIPIF section, tokenize it and look for tokens which produce such side-effects. if we don't find any relevant side-effects we can eval the in the main-process, instead of a isolated sub-process.

[staabm]

the upstream PHPUnit PR was merged and will be part of the next 11.5.x release

[staabm]

a similar change was merged today into symfony with symfony/symfony#58680

[jrfnl]

LGTM.

While the performance improvement will only be seen on PHPUnit 11.5, this change doesn't seem to negatively impact runs on older PHPUnit versions, so I see no reason not to merge this.

I also think it would be good to document this feature for PHPT tests, but that's a task for the PHPUnit website (which currently doesn't have any documentation on PHPT tests - see sebastianbergmann/phpunit-documentation-english#302 ).