feat: add type for failure during deleting dangling referrer index

[qweeah]

Resolves #479

[codecov-commenter]

Codecov Report

Merging #482 (be342e1) into main (e8225cb) will increase coverage by 0.08%.
The diff coverage is 63.63%.

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@@            Coverage Diff             @@
##             main     #482      +/-   ##
==========================================
+ Coverage   72.84%   72.92%   +0.08%     
==========================================
  Files          49       49              
  Lines        4518     4528      +10     
==========================================
+ Hits         3291     3302      +11     
  Misses        919      919              
+ Partials      308      307       -1     

Impacted Files	Coverage Δ
registry/remote/referrers.go	92.04% <33.33%> (-4.30%)	⬇️
registry/remote/repository.go	68.87% <100.00%> (+0.64%)	⬆️

[shizhMSFT]

LGTM

[sajayantony]

Is the digest of the manifest that failed to be deleted included in the errro?

[TerryHowe]

LGTM

Although please answer Sajay's question. Digest appears to be included to me.

[SteveLasker]

I'm struggling to understand why we'd delete content for the user: #479 (comment)

[qweeah]

Is the digest of the manifest that failed to be deleted included in the error?

It implicitly implied in the ReferrersTag, will add subject descriptor so caller don't need to do reversed conversion for referrers tag schema.

[shizhMSFT]

Since we may have more specific errors in the future. It would be better if we can introduce a generic error to avoid error type blow up.

A sample error can be

type ReferrersError struct {
    Op      string
    Subject ocispec.Descriptor
    Err     error
}

Other examples can be found by

• *os.LinkError
• *os.PathError
• *os.SyscallError

[qweeah]

type ReferrersError struct {
    Op      string
    Subject ocispec.Descriptor
    Err     error
}

Updated, made it more generic to a remote.IgnorableError, not only for referrers.

[sajayantony]

Ignorable is confusing to me. It’s up to the caller to decide that IMHO.

[shizhMSFT]

@qweeah It would be better if we can have a runnable example to show how this error can be parsed. Basically, we can have a mock registry which does not support delete.

[shizhMSFT]

LGTM

[TerryHowe]

LGTM

[Wwwsylvia]

LGTM