Asset::exists() loads the entire container listing to check one file #15607

Bug description

Asset::exists() (src/Assets/Asset.php:224) is $this->container()->files()->contains($path). files() resolves through AssetContainerContents::all(), which reads the whole cached recursive listing of the container into memory. AssetRepository::findById() → AssetContainer::asset() calls exists() on every lookup, so resolving a single asset reference on the front end costs a full listing load.

On a large S3 container this is fatal. One production site has a private container with 197,603 files; the cached listing (asset-list-contents-<handle>) is an 80 MB serialized string in Redis, and unserializing it pushes a PHP-FPM worker past a 1 GB memory_limit:

Allowed memory size of 1073741824 bytes exhausted (tried to allocate 80320709 bytes) at vendor/laravel/framework/src/Illuminate/Redis/Connections/Connection.php:124

Any page that renders an asset from that container pays this, not just the CP.

How to reproduce

1. Container on an S3 disk with a large number of files (tens of thousands is enough to see it; 197k reproduces the fatal at 1 GB).
2. STATAMIC_STACHE_FILE_WATCHER=false so the listing is cached forever.
3. Asset::find('private::some/file.jpg') from a front-end template or tinker and watch memory: the whole listing is loaded to answer one contains().

Logs

See above.

Environment

Statamic 6.35.0, Laravel 11, PHP 8.3, Redis cache, S3 (Flysystem v3) container, cache_meta true.

Installation

Existing Laravel app

Additional details

Suggested fix: make exists() answer without the listing when it can.

• If cache_meta is on and cacheStore()->has($this->metaCacheKey()) (meta cache is written only for assets that exist), return true without touching the listing.
• If the listing is already loaded in memory for this request (AssetContainerContents::$files is set, or Blink has it), use it as today.
• Otherwise fall back to a single $this->disk()->exists($path) (one S3 HEAD) instead of loading the listing.

The same pattern applies to metaExists() (src/Assets/Asset.php:316), which calls container()->metaFiles() and so also loads the full listing. A disk check on metaPath() works there too.

Tests to add in tests/Assets/AssetTest.php: exists() returns true from the meta cache without calling files(); falls back to the disk check when nothing is cached; still returns false for a missing path. Related: #11998 (meta as content) and a separate issue for excluding .meta files from the listing.