diff --git a/src/RequirementChecker/RequirementsBuilder.php b/src/RequirementChecker/RequirementsBuilder.php
index d8a5b4a2d..1cf8a9339 100644
--- a/src/RequirementChecker/RequirementsBuilder.php
+++ b/src/RequirementChecker/RequirementsBuilder.php
@@ -138,7 +138,7 @@ static function (array $sources): array {
                 usort(
                     $sources,
                     static fn (array $sourceTypePairA, array $sourceTypePairB) => strcmp(
-                        $sourceTypePairA[0],
+                        (string) $sourceTypePairA[0],
                         (string) $sourceTypePairB[0],
                     ),
                 );
diff --git a/tests/RequirementChecker/RequirementsBuilderTest.php b/tests/RequirementChecker/RequirementsBuilderTest.php
index f98cad507..a99cbef0f 100644
--- a/tests/RequirementChecker/RequirementsBuilderTest.php
+++ b/tests/RequirementChecker/RequirementsBuilderTest.php
@@ -108,9 +108,40 @@ public function test_it_can_build_requirements_from_provided_extensions(): void
             new Extension('http'),
             'package2',
         );
+        $this->builder->addProvidedExtension(
+            new Extension('http'),
+            null,
+        );
+
+        $expectedBuiltRequirements = new Requirements([]);
+        $expectedAllRequirements = new Requirements([
+            Requirement::forProvidedExtension('http', null),
+            Requirement::forProvidedExtension('http', 'package1'),
+            Requirement::forProvidedExtension('http', 'package2'),
+        ]);
+
+        $this->assertBuiltRequirementsEquals($expectedBuiltRequirements);
+        $this->assertAllRequirementsEquals($expectedAllRequirements);
+    }
+
+    public function test_it_can_build_requirements_from_provided_extensions_sorting_edge_case(): void
+    {
+        $this->builder->addProvidedExtension(
+            new Extension('http'),
+            null,
+        );
+        $this->builder->addProvidedExtension(
+            new Extension('http'),
+            'package1',
+        );
+        $this->builder->addProvidedExtension(
+            new Extension('http'),
+            'package2',
+        );
 
         $expectedBuiltRequirements = new Requirements([]);
         $expectedAllRequirements = new Requirements([
+            Requirement::forProvidedExtension('http', null),
             Requirement::forProvidedExtension('http', 'package1'),
             Requirement::forProvidedExtension('http', 'package2'),
         ]);