oc-mirror throws error when trying to mirror release payloads using digest with graph=true for nightly, rc and ec builds and does not generate signatures for ec and rc builds.
    

    [fedora@knarra-fedora knarra]$ ./oc-mirror version
W0210 13:19:40.701416  143622 mirror.go:102] 

⚠️  oc-mirror v1 is deprecated (starting in 4.18 release) and will be removed in a future release - please migrate to oc-mirror --v2

WARNING: This version information is deprecated and will be replaced with the output from --short. Use --output=yaml|json to get the full version.
Client Version: version.Info{Major:"", Minor:"", GitVersion:"4.18.0-202502041931.p0.gc7144d5.assembly.stream.el9-c7144d5", GitCommit:"c7144d5d2c2b0345f163299ed04a400f2f93d340", GitTreeState:"clean", BuildDate:"2025-02-04T20:04:49Z", GoVersion:"go1.22.9 (Red Hat 1.22.9-1.module+el8.10.0+22500+aee717ef) X:strictfipsruntime", Compiler:"gc", Platform:"linux/amd64"}

    

    Always
    

    1. use the nightly image set config as shown below and see that it throws an error
    2. use the rc candidate as shown below and see that it throws an error and does not generate signature relatted files
    3. use the ec candidate as shown below and see that it throws an error and does not generate signature related files.
    

    2025/02/10 12:15:49  [INFO]   : === Results ===
2025/02/10 12:15:49  [INFO]   :  ✓  191 / 191 release images mirrored successfully
2025/02/10 12:15:49  [INFO]   : 📄 Generating IDMS file...
2025/02/10 12:15:49  [INFO]   : internlrelease/working-dir/cluster-resources/idms-oc-mirror.yaml file created
2025/02/10 12:15:49  [INFO]   : 📄 No images by tag were mirrored. Skipping ITMS generation.
2025/02/10 12:15:49  [INFO]   : 📄 No catalogs mirrored. Skipping CatalogSource file generation.
2025/02/10 12:15:49  [INFO]   : 📄 No catalogs mirrored. Skipping ClusterCatalog file generation.
2025/02/10 12:15:49  [INFO]   : 📄 Generating UpdateService file...
2025/02/10 12:15:49  [INFO]   : 👋 Goodbye, thank you for using oc-mirror
2025/02/10 12:15:49  [ERROR]  : unknown image : reference name is empty 

    

     No errors should be seen and for ec and rc candidate signature should be generated as well.
    

with nightly payload and graph==true:
===============================
kind: ImageSetConfiguration
apiVersion: mirror.openshift.io/v2alpha1
mirror:
  platform:
    graph: true
    release: quay.io/openshift-release-dev/ocp-release@sha256:e0907823bc8989b02bb1bd55d5f08262dd0e4846173e792c14e7684fbd476c0d

with rc payload and graph==true:
===========================
[fedora@knarra-fedora knarra]$ cat /tmp/internal.yaml 
kind: ImageSetConfiguration
apiVersion: mirror.openshift.io/v2alpha1
mirror:
  platform:
    release: quay.io/openshift-release-dev/ocp-release@sha256:f0de3be10be2f5fc1a5b1c208bcfe5d3a71a70989cacbca57ebf7c5fe6e14b09
    graph: true

with ec payload and graph==true:
============================
[fedora@knarra-fedora knarra]$ cat /tmp/internal.yaml 
kind: ImageSetConfiguration
apiVersion: mirror.openshift.io/v2alpha1
mirror:
  platform:
    release: quay.io/openshift-release-dev/ocp-release@sha256:aa3e0a3a94babd90535f8298ab274b51a9bce6045dda8c3c8cd742bc59f0e2d9
    graph: true