regression: wrt zot since v0.16.0?

[rchincha]

What happened in your environment?

In context of #709, trying to figure out what broke.

Looks like a regression at 2329c6e.

First skopeo copy busybox:latest image into zot, then

With oras v0.16.0

$ORAS_PATH attach --plain-http $ORAS_REGISTRY_HOST/busybox:latest --artifact-type 'signature/example' ./signature.json:application/json
Exists    8a865c9da82b signature.json
Attached to localhost:8080/busybox@sha256:67bb7f36fcda428c491d7aa9a24ec0f1a8f6cdf472ef2c827ec7b6c2e36207f2
Digest: sha256:4e23167b9a8d41e8e95f51536b7333371fbf7b6bd993a9acc422a729150a9e90

With oras 2329c6e, see this error.

$ORAS_PATH attach --plain-http $ORAS_REGISTRY_HOST/busybox:latest --artifact-type 'signature/example' ./signature.json:application/json
Exists    8a865c9da82b signature.json
Error: sha256:efa88158fbb53aab65044fd2ec001fb855344a881461a1bf6171068eef4cee64: application/vnd.oci.artifact.manifest.v1+json: not found

What did you expect to happen?

No response

How can we reproduce it?

Pls see above.

What is the version of your ORAS CLI?

2329c6e

What is your OS environment?

ubuntu 22.04

Are you willing to submit PRs to fix it?

• Yes, I am willing to fix it.

[qweeah]

@rchincha Thanks a lot for investigating this issue. After taking a close look, this regression was introduced from oras-go library in oras-project/oras-go#359.

The manifest was packed into the file store, oras-go created a cache but the packed manifest was not cache. Should check whether the cache contains the descriptor in here.

cc oras-go maintainer @Wwwsylvia @shizhMSFT for tracking this issue in oras-go.