[v0.23] resolver: allow reference matches for local image lookups

[tonistiigi]

When looking up local images from container image store, Get() method only accepts direct name matches. This means that when image name is sent together with a digest value, it is not matched because containerd would expect digest to be part of the image name.

(cherry picked from commit 43580f9)

• resolver: allow reference matches for local image lookups #6029

[Copilot]

Pull Request Overview

This PR enhances the local image resolver to match references including digests by introducing a helper that parses the reference, constructs a name:tag, and verifies the digest when present.

• Replaced direct calls to is.Get(ctx, ref) with getImageByRef for both resolve modes
• Added getImageByRef to parse normalized names, handle tags/defaults, and enforce digest matching
• Imported github.com/containerd/errdefs to signal not-found errors

Comments suppressed due to low confidence (3)

util/resolver/pool.go:249

• [nitpick] Consider adding unit tests for getImageByRef to verify correct behavior when resolving references with only a digest, with both tag and digest, and when the digest does not match.

func getImageByRef(ctx context.Context, is images.Store, ref string) (images.Image, error) {

util/resolver/pool.go:267

• The code calls errors.WithStack but there is no import for a package that provides this function. Consider importing "github.com/pkg/errors" or using a standard fmt.Errorf with %w to wrap cerrdefs.ErrNotFound.

return images.Image{}, errors.WithStack(cerrdefs.ErrNotFound)

util/resolver/pool.go:256

• [nitpick] Replace the hardcoded "latest" with the constant distreference.DefaultTag to avoid a magic string and keep default tag semantics consistent.

tag := "latest"