Limit iterator in HookCollectorPass

Determine if we want to do this since we might be allowing Hook attributes elsewhere.

I think if we do that, we can undo or modify a change here. It is hard to tell without numbers on a real site, but my feeling is what we're currently doing is very, very i/o intensive and it should speed things up a lot if we can check less files.

I can't see files in submodules actually getting scanned.

When enabling navigation, this is the list of files it actually scans for that module:

core/modules/navigation/src/Hook/NavigationHooks.php
core/modules/navigation/navigation.install
core/modules/navigation/navigation.module

For paragraphs it's

modules/contrib/paragraphs/paragraphs.module
modules/contrib/paragraphs/paragraphs.install

Neither hook classes nor module files of submodules are being scanned. I used navigation because it has the navigation_top_bar module, which is AFAIK actually against core policy of not having submodules that aren't tests)

Thy are traversed, but they are filtered out.

*Maybe* it would be faster to use a separato recursive iterator just on the Hooks namespace and a non-recursive one on the module folder, but I suspect that's microoptimization and will not result in measurable performance improvements.

Yes, that is accurate, traversed is a better word.

beware, include files can be in subdirectories

Ah from hook hook info? I thought they had to be top level.

Any other includes would have to be manually included so they would be picked up.

HookCollectorPass currently indeed loads module which loads includes as well but it parses files return by the iterator to avoid reflection on those functions, who knows whether this is best practice but that's what it currently does so you need the iterator to return every include file wherever the module author has put them.

Yes I think we need to recursively scan for includes, but could still exclude /src. If you put a procedural include in /src... then you win a prize.

Hrmmmm yes that could be restricted. I have a feeling I wanted to based on how the code reads but I didn't, sorry. It's quite a bit of a fizzbuzz problem :) so there can be many ways to express this. Here's one

    $subPathname = $iterator->getSubPathname();
    $extension = $fileInfo->getExtension();
    // Under src/ only consider php files which are also under src/Hook.
    $inHook = str_starts_with($subPathname, 'src/Hook/');
    $isDir = $iterator->isDir();
    if ($isDir && ($subPathname === 'src' || $subPathname === 'src/Hook' || $inHook)) {
      return TRUE;
    }
    if ($inHook && $extension === 'php') {
      return TRUE;
    }
    if (str_starts_with($subPathname, 'src/')) {
      return FALSE;
    }
    // Otherwise traverse subdirectories as long as they are not submodules.
    return $isDir ?
      // glob() doesn't support streams but scandir() does.
      !in_array($fileInfo->getFilename(), ['tests', 'js', 'css']) && !array_filter(scandir($key), fn ($filename) => str_ends_with($filename, '.info.yml')) :
      in_array($extension, ['inc', 'module', 'profile', 'install']);