Use Statamic's own fast YAML parser where it has one

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Changed
+
+- **Statamic's own fast YAML parser is used where it has one.** Flatpack's copy is only used on Statamic versions without it.
+
 ## 1.1.0 (2026-11-10)
 
 ### Changed

src/Flatpack.php

@@ -21,6 +21,8 @@ public static function configure(string $path, int $lazyLimit = 2048): void
         self::$bodies = null;
     }
 
+    private static ?bool $statamicHasFastParser = null;
+
     public static function bodies(): BodyStore
     {
         return self::$bodies ??= new BodyStore(self::$path.'/bodies');
@@ -32,9 +34,22 @@ public static function parseFrontMatter(string $contents): array
         $fm = str_starts_with($contents, '---') ? preg_split("/\n---/", $contents, 2, PREG_SPLIT_NO_EMPTY)[0] : $contents;
         $fm = preg_replace('/^---\n?/', '', $fm);
 
+        if (self::statamicHasFastParser()) {
+            return (new \Statamic\Yaml\FastParser)->parse($fm) ?? [];
+        }
+
         return Yaml\FastParser::parse($fm) ?? SymfonyYaml::parse($fm) ?? [];
     }
 
+    /**
+     * Whether this Statamic version has its own fast YAML parser, which Flatpack then uses
+     * instead of the copy it ships for older versions.
+     */
+    public static function statamicHasFastParser(): bool
+    {
+        return self::$statamicHasFastParser ??= method_exists(\Statamic\Yaml\FastParser::class, 'parse');
+    }
+
     /** True when $v holds only scalars, nulls and arrays of them (safe for var_export + OPcache). */
     public static function isPlain($v): bool
     {

src/ServiceProvider.php

@@ -71,7 +71,10 @@ public function register(): void
         $this->app->booting(function ($app) {
             $app->bind(\Statamic\Contracts\Entries\Entry::class, FlatpackEntry::class);
             $app->bind(\Statamic\Stache\Traverser::class, Stache\FastTraverser::class);
-            $app->singleton(\Statamic\Yaml\Yaml::class, fn () => new LeanYaml(new Yaml\SymfonyFast));
+            // Statamic parses with its own fast parser where it has one; older versions get Flatpack's.
+            $app->singleton(\Statamic\Yaml\Yaml::class, fn () => new LeanYaml(
+                Flatpack::statamicHasFastParser() ? new \Symfony\Component\Yaml\Yaml : new Yaml\SymfonyFast
+            ));
             Facade::clearResolvedInstance(\Statamic\Yaml\Yaml::class);
         });
     }

src/Yaml/FastParser.php

@@ -17,6 +17,10 @@
  * collections or plain scalars, invalid YAML) makes it return null, and the caller parses the
  * whole document with Symfony. Errors are therefore always Symfony's.
  *
+ * Statamic has the same parser of its own from the release after 6.40 (statamic/cms#15838).
+ * Flatpack uses Statamic's where it exists and this one on older versions, Statamic 5 included
+ * (see Flatpack::statamicHasFastParser()).
+ *
  * tests/yaml/fuzz.php checks it against Symfony's parser.
  */
 final class FastParser