box-php85.patch

diff --git a/src/RequirementChecker/RequirementsBuilder.php b/src/RequirementChecker/RequirementsBuilder.php
index 1cf8a9339..77e558fef 100644
--- a/src/RequirementChecker/RequirementsBuilder.php
+++ b/src/RequirementChecker/RequirementsBuilder.php
@@ -58,6 +58,9 @@ public function addRequirement(Requirement $requirement): void

     public function addRequiredExtension(Extension $extension, ?string $source): void
     {
+        if (!$source) {
+            $source = '';
+        }
         $this->requiredExtensions[$extension->name][] = $source;
         $this->allExtensions[$extension->name][$source] = [$source, RequirementType::EXTENSION];
     }