---
version: "v1.0.8"
category: "experiments-updated"
---

#### `cas` — Malformed `cas::` references fail with a clear error

A `cas::` source with a malformed hash, such as `cas::sha1:a`, used to fail with an opaque internal error while looking the hash up in the store.

CAS references are now validated up front: the hash must be lowercase hexadecimal with exactly 40 characters for `sha1` or 64 for `sha256`. References that don't match are rejected with an error identifying the bad reference.
