Re-add support for JSON files with any file extension

The usage of Valinor's `Source::file()` method restricted the supported
file extensions to `.json`, not permitting JSON in e.g. `.txt` files.

Author: jeromegamez

CHANGELOG.md

@@ -7,11 +7,15 @@ Please read about the future of the Firebase Admin PHP SDK on the
 
 ## [Unreleased]
 
-## Added
+### Added
 
 * Re-added the `#[SensitiveParameter]` attribute because, while it's not supported in PHP 8.1, it can still be used
   if placed in a standalone line above the variable or property.
 
+### Fixed
+
+* Re-added support for JSON files with any file extension
+
 ## [7.21.1] - 2025-07-24
 
 ### Fixed

src/Firebase/Valinor/Source.php

@@ -24,25 +24,47 @@ private function __construct(
     ) {
     }
 
-    public static function parse(mixed $value): self
+    /**
+     * @param iterable<mixed>|string $value
+     */
+    public static function parse(iterable|string $value): self
     {
         if (is_iterable($value)) {
             return new self(BaseSource::iterable($value));
         }
 
-        if (str_starts_with((string) $value, '{') || str_starts_with((string) $value, '[')) {
-            try {
-                return new self(BaseSource::json($value));
-            } catch (Throwable $e) {
-                throw new InvalidArgumentException(message: $e->getMessage(), previous: $e);
-            }
+        if (str_starts_with($value, '{') || str_starts_with($value, '[')) {
+            return self::json($value);
         }
 
+        return self::file($value);
+    }
+
+    private static function json(string $value): self
+    {
+        try {
+            return new self(BaseSource::json($value));
+        } catch (Throwable $e) {
+            throw new InvalidArgumentException(message: $e->getMessage(), previous: $e);
+        }
+    }
+
+    public static function file(string $value): self
+    {
         try {
-            return new self(BaseSource::file(new SplFileObject($value)));
+            $file = new SplFileObject($value);
         } catch (Throwable $e) {
             throw new InvalidArgumentException(message: $e->getMessage(), previous: $e);
         }
+
+        $content = $file->fread($file->getSize());
+        $pathName = $file->getPathname();
+
+        if ($content === false) {
+            throw new InvalidArgumentException("Unable to parse `$pathName`");
+        }
+
+        return self::json($content);
     }
 
     public function getIterator(): Traversable

tests/Unit/Valinor/SourceTest.php

@@ -51,6 +51,14 @@ public function itSupportsJsonFiles(): void
         }
     }
 
+    #[Test]
+    public function itSupportsJsonFilesWithFileExtensionsNotSuggestingJson(): void
+    {
+        $source = Source::parse(__DIR__.'/valid.txt');
+
+        $this->assertSame(['foo' => 'bar'], iterator_to_array($source));
+    }
+
     #[Test]
     public function itRejectsInvalidFiles(): void
     {

tests/Unit/Valinor/valid.txt

@@ -0,0 +1 @@
+{"foo": "bar"}