In Phabricator, drop PhutilClassMap caches after loading additional libraries

Summary:
Depends on D16755. Right now, we build a setup check map (to run preflight checks), then later load libraries.

This means any checks included in third-party libraries don't get added to the map, and no longer run.

(These are rare, but Phacility has a couple).

Instead, delete the caches after loading extra libraries.

Test Plan: With this and D16755, re-ran setup checks and saw Phacility setup checks run.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D16756

src/infrastructure/env/PhabricatorEnv.php

@@ -202,6 +202,12 @@ final class PhabricatorEnv extends Phobject {
       phutil_load_library($library);
     }
 
+    // Drop any class map caches, since they will have generated without
+    // any classes from libraries. Without this, preflight setup checks can
+    // cause generation of a setup check cache that omits checks defined in
+    // libraries, for example.
+    PhutilClassMapQuery::deleteCaches();
+
     // If custom libraries specify config options, they won't get default
     // values as the Default source has already been loaded, so we get it to
     // pull in all options from non-phabricator libraries now they are loaded.