As I sit here running phpstan over and over to fix some issues. And kvetch to myself that every run in this one setup was taking 46seconds. I got to thinking: "Huh, even when nothing is changed, it seems to take that long. Shouldn't the resultCache/caching in general handle that?

So while doing other things I poked around a bit at the code, and ran xdebug profiling on it just cause I wanted to understand where all that time was going.

And if I understand what I saw correctly (I may not have):

1. In my case, 75% of the time was spent on two functions: php_strip_whitespace and PHPFileCleaner->clean
2. These are being called from OptimizedDirectorySourceLoader ...
3. Digging a bit more. This all seems to come from the findSymbol() step(s). Where when the OptimizedDirectorySourceLoader starts up, it ends up calling init() which in turn will basically walk the entire codetree, and create two lookup maps: $this->classToFile && $this->functionToFiles

If my quick poke/profile/playing around is correct, looks like this happens every time phpstan runs, regardless of the state of the cache. And these lookup tables themselves aren't cached.

If I'm right, is there a reason? Just curious, because in my case with a repo that (for reasons) may have like 50-80k PHP files that it needs to scan for symbols/functions ... and yeah, that's taking like 35s it looks like every time. If the output of those would be cached instead, that would dramatically speed stuff up (in my case)

But again, I may be misunderstanding exactly what's going on there. Just interesting and poking around