diff --git a/core/lib/Drupal/Core/Extension/ExtensionList.php b/core/lib/Drupal/Core/Extension/ExtensionList.php
index e50cda5..fee4048 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionList.php
@@ -91,6 +91,13 @@
   protected $addedFileNames = [];
 
   /**
+   * Static version of the added file names during the installer.
+   *
+   * @var string
+   */
+  protected static $staticAddedFileNames;
+
+  /**
    * The state.
    *
    * @var \Drupal\Core\State\StateInterface
@@ -140,7 +147,15 @@ public function reset() {
     $this->extensionInfo = NULL;
     $this->cache->delete($this->getInfoCacheId());
     $this->fileNames = NULL;
-    $this->state->delete($this->getFilenameCacheId());
+
+    try {
+      $this->state->delete($this->getFilenameCacheId());
+    }
+    catch (\Exception $e) {
+      // Ignore exceptions caused by a non existing {key_value} table in the
+      // early installer.
+    }
+
     $this->cache->delete($this->getFilenameCacheId());
     // We explicitly don't reset the addedFileNames as its sort of a static
     // cache.
@@ -442,9 +457,19 @@ protected function recalculateFilenames() {
    *   than by consulting the dynamic extension listing.
    *
    * @internal
+   *
+   * @see ::getFilename
    */
   public function setFilename($extension_name, $filename) {
     $this->addedFileNames[$extension_name] = $filename;
+
+    // In the early installer the container is rebuilt multiple times. Therefore
+    // we have to keep the added filenames across those rebuilds. This is not a
+    // final design, but rather just a workaround resolved at some point,
+    // hopefully.
+    if (!empty($GLOBALS['install_state'])) {
+      static::$staticAddedFileNames[$extension_name] = $filename;
+    }
   }
 
   /**
@@ -489,7 +514,10 @@ public function getFilename($extension_name) {
     elseif (isset($this->fileNames[$extension_name])) {
       return $this->fileNames[$extension_name];
     }
-    elseif ($file_names = $this->getFilenames() && isset($file_names[$extension_name])) {
+    elseif (isset(static::$staticAddedFileNames[$extension_name])) {
+      return static::$staticAddedFileNames[$extension_name];
+    }
+    elseif (($file_names = $this->getFilenames()) && isset($file_names[$extension_name])) {
       return $file_names[$extension_name];
     }
     throw new \InvalidArgumentException("The {$this->type} $extension_name does not exist.");
diff --git a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
index 7be828a..7d30840 100644
--- a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
@@ -73,32 +73,44 @@ protected function getExtensionDiscovery() {
     $discovery = parent::getExtensionDiscovery();
 
     if ($active_profile = $this->getActiveProfile()) {
-      // First, find profiles.
-      $discovery = new ExtensionDiscovery($this->root);
-      $discovery->setProfileDirectories([]);
-      $all_profiles = $discovery->scan('profile');
-      $profiles = array_intersect_key($all_profiles, $this->configFactory->get('core.extension')->get('module') ?: [$active_profile->getName() => 0]);
-
-      // If a module is within a profile directory but specifies another
-      // profile for testing, it needs to be found in the parent profile.
-      $settings = $this->configFactory->get('simpletest.settings')->get();
-      $parent_profile = !empty($settings['parent_profile']) ? $settings['parent_profile'] : NULL;
-      if ($parent_profile && !isset($profiles[$parent_profile])) {
-        // In case both profile directories contain the same extension, the
-        // actual profile always has precedence.
-        $profiles = [$parent_profile => $all_profiles[$parent_profile]] + $profiles;
-      }
-
-      $profile_directories = array_map(function (Extension $profile) {
-        return $profile->getPath();
-      }, $profiles);
-      $discovery->setProfileDirectories($profile_directories);
+      $discovery->setProfileDirectories($this->getProfileDirectories($discovery));
     }
 
     return $discovery;
   }
 
   /**
+   * Finds all installation profile paths.
+   *
+   * @param \Drupal\Core\Extension\ExtensionDiscovery $discovery
+   *   The extension discovery.
+   *
+   * @return array
+   *   Paths to all installation profiles.
+   */
+  protected function getProfileDirectories(ExtensionDiscovery $discovery) {
+    $discovery->setProfileDirectories([]);
+    $all_profiles = $discovery->scan('profile');
+    $profiles = array_intersect_key($all_profiles, $this->configFactory->get('core.extension')->get('module') ?: [$active_profile->getName() => 0]);
+
+    // If a module is within a profile directory but specifies another
+    // profile for testing, it needs to be found in the parent profile.
+    $settings = $this->configFactory->get('simpletest.settings')->get();
+    $parent_profile = !empty($settings['parent_profile']) ? $settings['parent_profile'] : NULL;
+
+    if ($parent_profile && !isset($profiles[$parent_profile])) {
+      // In case both profile directories contain the same extension, the
+      // actual profile always has precedence.
+      $profiles = [$parent_profile => $all_profiles[$parent_profile]] + $profiles;
+    }
+
+    $profile_directories = array_map(function (Extension $profile) {
+      return $profile->getPath();
+    }, $profiles);
+    return $profile_directories;
+  }
+
+  /**
    * Gets the processed active profile object, or null.
    *
    * @return \Drupal\Core\Extension\Extension|null
diff --git a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
index c65dac9..77f24c1 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
@@ -253,9 +253,7 @@ protected function getInstalledExtensionsNames() {
    * {@inheritdoc}
    */
   protected function getExtensionDiscovery() {
-    return NULL !== $this->extensionDiscovery
-      ? $this->extensionDiscovery
-      : parent::getExtensionDiscovery();
+    return $this->extensionDiscovery ?: parent::getExtensionDiscovery();
   }
 
 }