[staabm]

➜  phpstan-src git:(strpbrk) ✗ php tests/bench/micro/trailing-whitespace.php                                 
PHP 8.5.12; PCRE JIT: 1; 200000 iterations, median of 5 rounds
Input                   Strings ns/op   strspn ns/op    speedup
empty                           294.8           18.3     16.12x
newline                         306.8           32.2      9.54x
whitespace                      319.3           34.4      9.29x
long whitespace                 388.7           90.3      4.31x
html                            292.9           31.5      9.29x
late non-whitespace             471.3           94.2      5.01x

[staabm]

//cc @SanderMuller

[phpstan-bot]

This pull request has been marked as ready for review.

[SanderMuller]

The new check gives the same result as the old regex. I compared both on 201,281 strings. These were every byte value alone and next to a space or a newline. They also included random strings of up to 8 characters made from whitespace, \x85, \xA0, NUL and a letter. There was no difference, also with the UTF-8 ctype locale that the CLI sets.

There is one difference, and it is a fix. On 2,000,000 spaces followed by x, Strings::match() throws RegexpException: Backtrack limit was exhausted, with and without JIT. strspn() gives the correct result there.

The existing tests cover the change: 2 of the 5 rule tests fail when the new condition always skips. On the PR head, the rule tests, phpcs and make phpstan pass. The 4 red integration jobs are also red on #7007.

The effect on a full run is small. In self-analysis the rule checks 5,884 last nodes in 2,947 files, and only an InlineHTML node gets to strspn(). With the largest saving in your table, that is at most about 2 ms per run.