bug symfony#57553 [HttpKernel] Enable optional cache-warmers when cache-dir != build-dir (nicolas-grekas)

This PR was merged into the 6.4 branch.

Discussion
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[HttpKernel] Enable optional cache-warmers when cache-dir != build-dir

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Issues        | -
| License       | MIT

We should be running optional cache warmers during kernel compilation when cache-dir != build-dir. This gives them an opportunity to run, which is missing right now.

Commits
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7aa625b [HttpKernel] Enable optional cache-warmers when cache-dir != build-dir

Author: nicolas-grekas

src/Symfony/Component/HttpKernel/Kernel.php

@@ -539,10 +539,17 @@ protected function initializeContainer()
             touch($oldContainerDir.'.legacy');
         }
 
-        $preload = $this instanceof WarmableInterface ? (array) $this->warmUp($this->container->getParameter('kernel.cache_dir'), $buildDir) : [];
+        $cacheDir = $this->container->getParameter('kernel.cache_dir');
+        $preload = $this instanceof WarmableInterface ? (array) $this->warmUp($cacheDir, $buildDir) : [];
 
         if ($this->container->has('cache_warmer')) {
-            $preload = array_merge($preload, (array) $this->container->get('cache_warmer')->warmUp($this->container->getParameter('kernel.cache_dir'), $buildDir));
+            $cacheWarmer = $this->container->get('cache_warmer');
+
+            if ($cacheDir !== $buildDir) {
+                $cacheWarmer->enableOptionalWarmers();
+            }
+
+            $preload = array_merge($preload, (array) $cacheWarmer->warmUp($cacheDir, $buildDir));
         }
 
         if ($preload && file_exists($preloadFile = $buildDir.'/'.$class.'.preload.php')) {