Issue #3411392: Build tests fail on core merge requests

package_manager/tests/src/Build/TemplateProjectTestBase.php

@@ -270,6 +270,10 @@ END;
     // Allow pre-release versions of dependencies.
     $this->runComposer('composer config minimum-stability dev', $template_dir);
 
+    // CORE_MR_ONLY:// Allow any version of Drupal core as in test using a git clone on Gitlab
+    // CORE_MR_ONLY:// core will be checked out at a specific commit hash.
+    // CORE_MR_ONLY:$this->runComposer("composer require --no-update drupal/core:'*'", "composer/Metapackage/CoreRecommended");
+
     // Remove the packages.drupal.org entry (and any other custom repository)
     // from the template's repositories section. We have no reliable way of
     // knowing the repositories' names in advance, so we get that information

scripts/src/ConverterCommand.php

@@ -155,7 +155,15 @@ class ConverterCommand extends Command {
     static::info("Applying core patches");
     print_r($patches);
     foreach ($patches as $file) {
-      static::executeCommand("patch -d{$this->core_dir} -p1 < $file");
+      $patch_result = NULL;
+      $output = [];
+      // Patch but ignore previously applied patches.
+      exec("patch -d{$this->core_dir} -p1 -N -r - < $file", $output, $patch_result);
+      if ($patch_result !== 0) {
+        if (!str_contains(implode("\n", $output), 'Ignoring previously applied (or reversed) patch.')) {
+          throw new \Exception("Patch failed: $file");
+        }
+      }
     }
 
     // Switch to the core directory and require all of the packages there are in