reference: remove support for deprecated "shortid" refs

The "shortid" syntax was added in d26a3b37a6,
and allowed for matching an image on its ID prefix (this is before images were
content-addressable). With the introduction of content-addressable references,
this syntax became problematic, and Docker deprecated this syntax in 2016
(Docker v1.13.0) through commit; 5fc71599a0

> The `repository:shortid` syntax for referencing images is very little used,
> collides with tag references, and can be confused with digest references.

Support for this syntax was removed in 2017 (Docker 17.12) through commit:
a942c92dd7

containerd uses a fork of the reference package with this syntax removed, and
does not support this syntax:
901bcb2231

This patch removes the deprecated syntax, the ParseAnyReferenceWithSet function,
and the ShortIdentifierRegexp regex.

As there are no external consumers for this function, nor the regexp, I'm
skipping a deprecation cycle for this;

- https://grep.app/search?q=.ShortIdentifierRegexp
- https://grep.app/search?q=.ParseAnyReferenceWithSet%28

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

reference/normalize.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/distribution/distribution/v3/digestset"
 	"github.com/opencontainers/go-digest"
 )
 
@@ -179,20 +178,3 @@ func ParseAnyReference(ref string) (Reference, error) {
 
 	return ParseNormalizedNamed(ref)
 }
-
-// ParseAnyReferenceWithSet parses a reference string as a possible short
-// identifier to be matched in a digest set, a full digest, or familiar name.
-func ParseAnyReferenceWithSet(ref string, ds *digestset.Set) (Reference, error) {
-	if ok := anchoredShortIdentifierRegexp.MatchString(ref); ok {
-		dgst, err := ds.Lookup(ref)
-		if err == nil {
-			return digestReference(dgst), nil
-		}
-	} else {
-		if dgst, err := digest.Parse(ref); err == nil {
-			return digestReference(dgst), nil
-		}
-	}
-
-	return ParseNormalizedNamed(ref)
-}

reference/normalize_test.go

@@ -4,7 +4,6 @@ import (
 	"strconv"
 	"testing"
 
-	"github.com/distribution/distribution/v3/digestset"
 	"github.com/opencontainers/go-digest"
 )
 
@@ -360,7 +359,6 @@ func TestParseAnyReference(t *testing.T) {
 		Reference  string
 		Equivalent string
 		Expected   Reference
-		Digests    []digest.Digest
 	}{
 		{
 			Reference:  "redis",
@@ -416,62 +414,16 @@ func TestParseAnyReference(t *testing.T) {
 			Reference:  "dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9",
 			Equivalent: "docker.io/library/dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9",
 		},
-		{
-			Reference:  "dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9",
-			Expected:   digestReference("sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			Equivalent: "sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c",
-			Digests: []digest.Digest{
-				digest.Digest("sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-				digest.Digest("sha256:abcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			},
-		},
-		{
-			Reference:  "dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9",
-			Equivalent: "docker.io/library/dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9",
-			Digests: []digest.Digest{
-				digest.Digest("sha256:abcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			},
-		},
-		{
-			Reference:  "dbcc1c",
-			Expected:   digestReference("sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			Equivalent: "sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c",
-			Digests: []digest.Digest{
-				digest.Digest("sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-				digest.Digest("sha256:abcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			},
-		},
 		{
 			Reference:  "dbcc1",
 			Equivalent: "docker.io/library/dbcc1",
-			Digests: []digest.Digest{
-				digest.Digest("sha256:dbcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-				digest.Digest("sha256:abcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			},
-		},
-		{
-			Reference:  "dbcc1c",
-			Equivalent: "docker.io/library/dbcc1c",
-			Digests: []digest.Digest{
-				digest.Digest("sha256:abcc1c35ac38df41fd2f5e4130b32ffdb93ebae8b3dbe638c23575912276fc9c"),
-			},
 		},
 	}
 
 	for _, tcase := range tcases {
 		var ref Reference
 		var err error
-		if len(tcase.Digests) == 0 {
+		ref, err = ParseAnyReference(tcase.Reference)
-			ref, err = ParseAnyReference(tcase.Reference)
-		} else {
-			ds := digestset.NewSet()
-			for _, dgst := range tcase.Digests {
-				if err := ds.Add(dgst); err != nil {
-					t.Fatalf("Error adding digest %s: %v", dgst.String(), err)
-				}
-			}
-			ref, err = ParseAnyReferenceWithSet(tcase.Reference, ds)
-		}
 		if err != nil {
 			t.Fatalf("Error parsing reference %s: %v", tcase.Reference, err)
 		}

reference/regexp.go

@@ -112,22 +112,10 @@ var (
 	// are like digests without the algorithm, since sha256 is used.
 	IdentifierRegexp = regexp.MustCompile(identifier)
 
-	shortIdentifier = `([a-f0-9]{6,64})`
-	// ShortIdentifierRegexp is the format used to represent a prefix
-	// of an identifier. A prefix may be used to match a sha256 identifier
-	// within a list of trusted identifiers.
-	ShortIdentifierRegexp = regexp.MustCompile(shortIdentifier)
-
 	anchoredIdentifier = anchored(identifier)
 	// anchoredIdentifierRegexp is used to check or match an
 	// identifier value, anchored at start and end of string.
 	anchoredIdentifierRegexp = regexp.MustCompile(anchoredIdentifier)
-
-	anchoredShortIdentifier = anchored(shortIdentifier)
-	// anchoredShortIdentifierRegexp is used to check if a value
-	// is a possible identifier prefix, anchored at start and end
-	// of string.
-	anchoredShortIdentifierRegexp = regexp.MustCompile(anchoredShortIdentifier)
 )
 
 // literal compiles s into a literal regular expression, escaping any regexp

reference/regexp_test.go

@@ -550,43 +550,7 @@ func TestIdentifierRegexp(t *testing.T) {
 			match: false,
 		},
 	}
-
-	shortCases := []regexpMatch{
-		{
-			input: "da304e823d8ca2b9d863a3c897baeb852ba21ea9a9f1414736394ae7fcaf9821",
-			match: true,
-		},
-		{
-			input: "7EC43B381E5AEFE6E04EFB0B3F0693FF2A4A50652D64AEC573905F2DB5889A1C",
-			match: false,
-		},
-		{
-			input: "da304e823d8ca2b9d863a3c897baeb852ba21ea9a9f1414736394ae7fcaf",
-			match: true,
-		},
-		{
-			input: "sha256:da304e823d8ca2b9d863a3c897baeb852ba21ea9a9f1414736394ae7fcaf9821",
-			match: false,
-		},
-		{
-			input: "da304e823d8ca2b9d863a3c897baeb852ba21ea9a9f1414736394ae7fcaf98218482",
-			match: false,
-		},
-		{
-			input: "da304",
-			match: false,
-		},
-		{
-			input: "da304e",
-			match: true,
-		},
-	}
-
 	for i := range fullCases {
 		checkRegexp(t, anchoredIdentifierRegexp, fullCases[i])
 	}
-
-	for i := range shortCases {
-		checkRegexp(t, anchoredShortIdentifierRegexp, shortCases[i])
-	}
 }