Sort transitive tips instead of ksorting a list

[ondrejmirtes]

buildError() collects transitive tips into a list:

$tips = [];

foreach (array_slice($blackMembersGroup, 1) as $transitivelyDeadMember) {
    $tips[] = $this->buildTransitiveErrorMessages($transitivelyDeadMember) . $exclusionMessage;
    // ...
}

$builder->metadata($metadata);

ksort($tips);

Since $tips is appended to with $tips[], its keys are already 0..n-1 in ascending order, so ksort() is a no-op. The tips are emitted in insertion order, which is the order of getTransitiveDeadCalls() → the insertion order of $usageGraph → the order PHPStan hands over collected data. That last one is not stable across parallel runs.

I noticed this while profiling the extension on a ~16k-file codebase: two runs of identical code produced different tip order for the same error, so diffing analysis output between runs showed spurious changes.

The existing test expectations show the same thing — Grouping\Example::boo and Grouping\Example::foo have the same three transitively dead members, but the fixture encoded them in two different orders:

'Unused Grouping\Example::boo',
"• Thus Grouping\Example::bag is transitively unused\n" .
"• Thus Grouping\Example::bar is transitively unused\n" .
'• Thus Grouping\Example::TRANSITIVELY_UNUSED_CONST is transitively unused',

'Unused Grouping\Example::foo',
"• Thus Grouping\Example::bar is transitively unused\n" .   // <- flipped
"• Thus Grouping\Example::bag is transitively unused\n" .
'• Thus Grouping\Example::TRANSITIVELY_UNUSED_CONST is transitively unused',

sort($tips) gives the deterministic order the ksort() call was clearly reaching for. I updated the three affected expectations; the full suite passes (858 tests), as do phpstan and phpcs.

I also opened phpstan/phpstan#15126 asking for a rule that reports ksort() on a list, since PHPStan already reports the analogous array_values() on a list and would have caught this.

[janedbal]

Good catch, thanks! This is a regression: originally fixed in #146 by keying the tips by member ref (making the ksort() meaningful), then broken in #281 which switched to plain $tips[] = ... appends while keeping the ksort(). Your sort() fix looks good.