Return file path in archive type exception

composer.json

@@ -50,7 +50,7 @@
       "./vendor/bin/phpcpd --suffix='.php' src"
     ],
     "phpunit": [
-      "phpdbg -qrr ./vendor/bin/phpunit -d memory_limit=-1 --testsuite BagIt"
+      "phpdbg -qrr ./vendor/bin/phpunit -d memory_limit=-1 --verbose --testsuite BagIt"
     ],
     "test": [
       "@check",

src/Bag.php

@@ -418,7 +418,7 @@ public function package(string $filepath): void
     {
         if (!self::hasExtension($filepath, $this->packageExtensions)) {
             throw new BagItException(
-                "Unknown archive type, the file extension must be one of (" .
+                "Unknown archive type ($filepath), the file extension must be one of (" .
                 implode(", ", $this->packageExtensions) . ")"
             );
         }
@@ -2186,18 +2186,17 @@ private static function getExtension(string $filepath): ?string
     {
         $filename = strtolower(basename($filepath));
         $pathinfo = pathinfo($filename);
-        $extensions = [$pathinfo['extension']] ?? null;
+        $extensions = [];
+        $extensions[] = $pathinfo['extension'] ?? null;
         while (strpos($pathinfo['filename'], ".") > -1) {
             $pathinfo = pathinfo($pathinfo['filename']);
             $extensions[] = $pathinfo['extension'] ?? null;
         }
         $extensions = array_filter($extensions);
         if (count($extensions) > 0) {
-            $extension = implode(".", array_reverse($extensions));
-        } else {
-            $extension = null;
+            return implode(".", array_reverse($extensions));
         }
-        return $extension;
+        return null;
     }
 
     /**

tests/BagTest.php

@@ -838,8 +838,8 @@ public function testInvalidPackage(): void
         $this->assertFileDoesNotExist($archivefile);
 
         $this->expectException(BagItException::class);
-        $this->expectExceptionMessage("Unknown archive type, the file extension must be one of (tar, tgz, tar.gz, " .
-            "tar.bz2, zip)");
+        $this->expectExceptionMessage("Unknown archive type ($archivefile), the file extension must be one of (tar, " .
+            "tgz, tar.gz, tar.bz2, zip)");
 
         $bag->package($archivefile);
     }