From 5f16ea7b5b1d4edcd4be21bf7963dafead9686ea Mon Sep 17 00:00:00 2001
From: Tim Otten <totten@civicrm.org>
Date: Wed, 1 Apr 2020 01:00:07 -0700
Subject: [PATCH] dev/core#1674 - Update container cache when folder is removed
 or created

Conceptually, you want to:

* (A) Keep the container cache when nothing has changed (regardless of whether that status-quo has an API4 subscriber folder).
* (B) Update the cache if Civi/Api4/Event/Subscriber/*.php has been newly created
* (C) Update the cache if Civi/Api4/Event/Subscriber/*.php has been newly removed

To test this out, I hacked `Civi\Core\Container::loadContainer()` to emit a debug message
to indicate if it is reusing the cache or updating. Then, I prepared two terminals for running alternate steps:

* In terminal 1, go back and forth with adding/removing folders/files like `Civi/Api4/Event/Subscriber`.
* In terminal 2, periodically run `cv ev 'echo "Hello\n";'` and note whether the cache is update.

In this way, we can see if a developer action (adding a file) leads to an automatic update in the cache.

I found that the previous commit fixed (A) and did (C), but it failed to
update per (B).  This commit should handle (A), (B), and (C).
---
 CRM/Api4/Services.php | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/CRM/Api4/Services.php b/CRM/Api4/Services.php
index c00487df5f..fba89627dd 100644
--- a/CRM/Api4/Services.php
+++ b/CRM/Api4/Services.php
@@ -81,9 +81,14 @@ class CRM_Api4_Services {
     );
     foreach ($locations as $location) {
       $path = \CRM_Utils_File::addTrailingSlash(dirname($location)) . str_replace('\\', DIRECTORY_SEPARATOR, $namespace);
+      if (!file_exists($path) || !is_dir($path)) {
+        $resource = new \Symfony\Component\Config\Resource\FileExistenceResource($path);
+        $container->addResource($resource);
+        continue;
+      }
+
       try {
         $resource = new \Symfony\Component\Config\Resource\DirectoryResource($path, ';\.php$;');
-        $addResource = FALSE;
         foreach (glob("$path*.php") as $file) {
           $matches = [];
           preg_match('/(\w*)\.php$/', $file, $matches);
@@ -92,15 +97,18 @@ class CRM_Api4_Services {
           if ($serviceClass->isInstantiable()) {
             $definition = $container->register(str_replace('\\', '_', $serviceName), $serviceName);
             $definition->addTag($tag);
-            $addResource = TRUE;
           }
         }
-        if ($addResource) {
-          $container->addResource($resource);
-        }
+        $container->addResource($resource);
       }
       catch (\InvalidArgumentException $e) {
         //Directory is not found so lets not do anything i suppose.
+
+        // FIXME: The above comment implies that the try/catch is specifically
+        // about the directory's existence, which would make it redundant with the
+        // newer "file_exists()" guard. However, the actual "catch()" seems broader,
+        // and I don't see anything in DirectoryResource that throws the exception.
+        // So... maybe it's not needed, or maybe there's some additional purpose.
       }
     }
   }
-- 
2.25.1