vendor: update to compose-go 1.13.4

Signed-off-by: Nick Sieger <nick@nicksieger.com>

vendor/github.com/distribution/distribution/v3/digestset/set.go

@@ -1,247 +0,0 @@
-package digestset
-
-import (
-	"errors"
-	"sort"
-	"strings"
-	"sync"
-
-	digest "github.com/opencontainers/go-digest"
-)
-
-var (
-	// ErrDigestNotFound is used when a matching digest
-	// could not be found in a set.
-	ErrDigestNotFound = errors.New("digest not found")
-
-	// ErrDigestAmbiguous is used when multiple digests
-	// are found in a set. None of the matching digests
-	// should be considered valid matches.
-	ErrDigestAmbiguous = errors.New("ambiguous digest string")
-)
-
-// Set is used to hold a unique set of digests which
-// may be easily referenced by easily  referenced by a string
-// representation of the digest as well as short representation.
-// The uniqueness of the short representation is based on other
-// digests in the set. If digests are omitted from this set,
-// collisions in a larger set may not be detected, therefore it
-// is important to always do short representation lookups on
-// the complete set of digests. To mitigate collisions, an
-// appropriately long short code should be used.
-type Set struct {
-	mutex   sync.RWMutex
-	entries digestEntries
-}
-
-// NewSet creates an empty set of digests
-// which may have digests added.
-func NewSet() *Set {
-	return &Set{
-		entries: digestEntries{},
-	}
-}
-
-// checkShortMatch checks whether two digests match as either whole
-// values or short values. This function does not test equality,
-// rather whether the second value could match against the first
-// value.
-func checkShortMatch(alg digest.Algorithm, hex, shortAlg, shortHex string) bool {
-	if len(hex) == len(shortHex) {
-		if hex != shortHex {
-			return false
-		}
-		if len(shortAlg) > 0 && string(alg) != shortAlg {
-			return false
-		}
-	} else if !strings.HasPrefix(hex, shortHex) {
-		return false
-	} else if len(shortAlg) > 0 && string(alg) != shortAlg {
-		return false
-	}
-	return true
-}
-
-// Lookup looks for a digest matching the given string representation.
-// If no digests could be found ErrDigestNotFound will be returned
-// with an empty digest value. If multiple matches are found
-// ErrDigestAmbiguous will be returned with an empty digest value.
-func (dst *Set) Lookup(d string) (digest.Digest, error) {
-	dst.mutex.RLock()
-	defer dst.mutex.RUnlock()
-	if len(dst.entries) == 0 {
-		return "", ErrDigestNotFound
-	}
-	var (
-		searchFunc func(int) bool
-		alg        digest.Algorithm
-		hex        string
-	)
-	dgst, err := digest.Parse(d)
-	if err == digest.ErrDigestInvalidFormat {
-		hex = d
-		searchFunc = func(i int) bool {
-			return dst.entries[i].val >= d
-		}
-	} else {
-		hex = dgst.Hex()
-		alg = dgst.Algorithm()
-		searchFunc = func(i int) bool {
-			if dst.entries[i].val == hex {
-				return dst.entries[i].alg >= alg
-			}
-			return dst.entries[i].val >= hex
-		}
-	}
-	idx := sort.Search(len(dst.entries), searchFunc)
-	if idx == len(dst.entries) || !checkShortMatch(dst.entries[idx].alg, dst.entries[idx].val, string(alg), hex) {
-		return "", ErrDigestNotFound
-	}
-	if dst.entries[idx].alg == alg && dst.entries[idx].val == hex {
-		return dst.entries[idx].digest, nil
-	}
-	if idx+1 < len(dst.entries) && checkShortMatch(dst.entries[idx+1].alg, dst.entries[idx+1].val, string(alg), hex) {
-		return "", ErrDigestAmbiguous
-	}
-
-	return dst.entries[idx].digest, nil
-}
-
-// Add adds the given digest to the set. An error will be returned
-// if the given digest is invalid. If the digest already exists in the
-// set, this operation will be a no-op.
-func (dst *Set) Add(d digest.Digest) error {
-	if err := d.Validate(); err != nil {
-		return err
-	}
-	dst.mutex.Lock()
-	defer dst.mutex.Unlock()
-	entry := &digestEntry{alg: d.Algorithm(), val: d.Hex(), digest: d}
-	searchFunc := func(i int) bool {
-		if dst.entries[i].val == entry.val {
-			return dst.entries[i].alg >= entry.alg
-		}
-		return dst.entries[i].val >= entry.val
-	}
-	idx := sort.Search(len(dst.entries), searchFunc)
-	if idx == len(dst.entries) {
-		dst.entries = append(dst.entries, entry)
-		return nil
-	} else if dst.entries[idx].digest == d {
-		return nil
-	}
-
-	entries := append(dst.entries, nil)
-	copy(entries[idx+1:], entries[idx:len(entries)-1])
-	entries[idx] = entry
-	dst.entries = entries
-	return nil
-}
-
-// Remove removes the given digest from the set. An err will be
-// returned if the given digest is invalid. If the digest does
-// not exist in the set, this operation will be a no-op.
-func (dst *Set) Remove(d digest.Digest) error {
-	if err := d.Validate(); err != nil {
-		return err
-	}
-	dst.mutex.Lock()
-	defer dst.mutex.Unlock()
-	entry := &digestEntry{alg: d.Algorithm(), val: d.Hex(), digest: d}
-	searchFunc := func(i int) bool {
-		if dst.entries[i].val == entry.val {
-			return dst.entries[i].alg >= entry.alg
-		}
-		return dst.entries[i].val >= entry.val
-	}
-	idx := sort.Search(len(dst.entries), searchFunc)
-	// Not found if idx is after or value at idx is not digest
-	if idx == len(dst.entries) || dst.entries[idx].digest != d {
-		return nil
-	}
-
-	entries := dst.entries
-	copy(entries[idx:], entries[idx+1:])
-	entries = entries[:len(entries)-1]
-	dst.entries = entries
-
-	return nil
-}
-
-// All returns all the digests in the set
-func (dst *Set) All() []digest.Digest {
-	dst.mutex.RLock()
-	defer dst.mutex.RUnlock()
-	retValues := make([]digest.Digest, len(dst.entries))
-	for i := range dst.entries {
-		retValues[i] = dst.entries[i].digest
-	}
-
-	return retValues
-}
-
-// ShortCodeTable returns a map of Digest to unique short codes. The
-// length represents the minimum value, the maximum length may be the
-// entire value of digest if uniqueness cannot be achieved without the
-// full value. This function will attempt to make short codes as short
-// as possible to be unique.
-func ShortCodeTable(dst *Set, length int) map[digest.Digest]string {
-	dst.mutex.RLock()
-	defer dst.mutex.RUnlock()
-	m := make(map[digest.Digest]string, len(dst.entries))
-	l := length
-	resetIdx := 0
-	for i := 0; i < len(dst.entries); i++ {
-		var short string
-		extended := true
-		for extended {
-			extended = false
-			if len(dst.entries[i].val) <= l {
-				short = dst.entries[i].digest.String()
-			} else {
-				short = dst.entries[i].val[:l]
-				for j := i + 1; j < len(dst.entries); j++ {
-					if checkShortMatch(dst.entries[j].alg, dst.entries[j].val, "", short) {
-						if j > resetIdx {
-							resetIdx = j
-						}
-						extended = true
-					} else {
-						break
-					}
-				}
-				if extended {
-					l++
-				}
-			}
-		}
-		m[dst.entries[i].digest] = short
-		if i >= resetIdx {
-			l = length
-		}
-	}
-	return m
-}
-
-type digestEntry struct {
-	alg    digest.Algorithm
-	val    string
-	digest digest.Digest
-}
-
-type digestEntries []*digestEntry
-
-func (d digestEntries) Len() int {
-	return len(d)
-}
-
-func (d digestEntries) Less(i, j int) bool {
-	if d[i].val != d[j].val {
-		return d[i].val < d[j].val
-	}
-	return d[i].alg < d[j].alg
-}
-
-func (d digestEntries) Swap(i, j int) {
-	d[i], d[j] = d[j], d[i]
-}

vendor/github.com/distribution/distribution/v3/reference/fuzz.go

@@ -1,12 +0,0 @@
-// +build gofuzz
-
-package reference
-
-// fuzzParseNormalizedNamed implements a fuzzer
-// that targets ParseNormalizedNamed
-// Export before building the fuzzer.
-// nolint:deadcode
-func fuzzParseNormalizedNamed(data []byte) int {
-	_, _ = ParseNormalizedNamed(string(data))
-	return 1
-}

vendor/github.com/distribution/distribution/v3/reference/helpers.go

@@ -32,7 +32,7 @@ func FamiliarString(ref Reference) string {
 }
 
 // FamiliarMatch reports whether ref matches the specified pattern.
-// See https://godoc.org/path#Match for supported patterns.
+// See [path.Match] for supported patterns.
 func FamiliarMatch(pattern string, ref Reference) (bool, error) {
 	matched, err := path.Match(pattern, FamiliarString(ref))
 	if namedRef, isNamed := ref.(Named); isNamed && !matched {

vendor/github.com/distribution/distribution/v3/reference/normalize.go

@@ -4,15 +4,39 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/distribution/distribution/v3/digestset"
 	"github.com/opencontainers/go-digest"
 )
 
-var (
+const (
+	// legacyDefaultDomain is the legacy domain for Docker Hub (which was
+	// originally named "the Docker Index"). This domain is still used for
+	// authentication and image search, which were part of the "v1" Docker
+	// registry specification.
+	//
+	// This domain will continue to be supported, but there are plans to consolidate
+	// legacy domains to new "canonical" domains. Once those domains are decided
+	// on, we must update the normalization functions, but preserve compatibility
+	// with existing installs, clients, and user configuration.
 	legacyDefaultDomain = "index.docker.io"
-	defaultDomain       = "docker.io"
-	officialRepoName    = "library"
-	defaultTag          = "latest"
+
+	// defaultDomain is the default domain used for images on Docker Hub.
+	// It is used to normalize "familiar" names to canonical names, for example,
+	// to convert "ubuntu" to "docker.io/library/ubuntu:latest".
+	//
+	// Note that actual domain of Docker Hub's registry is registry-1.docker.io.
+	// This domain will continue to be supported, but there are plans to consolidate
+	// legacy domains to new "canonical" domains. Once those domains are decided
+	// on, we must update the normalization functions, but preserve compatibility
+	// with existing installs, clients, and user configuration.
+	defaultDomain = "docker.io"
+
+	// officialRepoPrefix is the namespace used for official images on Docker Hub.
+	// It is used to normalize "familiar" names to canonical names, for example,
+	// to convert "ubuntu" to "docker.io/library/ubuntu:latest".
+	officialRepoPrefix = "library/"
+
+	// defaultTag is the default tag if no tag is provided.
+	defaultTag = "latest"
 )
 
 // normalizedNamed represents a name which has been
@@ -34,14 +58,14 @@ func ParseNormalizedNamed(s string) (Named, error) {
 		return nil, fmt.Errorf("invalid repository name (%s), cannot specify 64-byte hexadecimal strings", s)
 	}
 	domain, remainder := splitDockerDomain(s)
-	var remoteName string
+	var remote string
 	if tagSep := strings.IndexRune(remainder, ':'); tagSep > -1 {
-		remoteName = remainder[:tagSep]
+		remote = remainder[:tagSep]
 	} else {
-		remoteName = remainder
+		remote = remainder
 	}
-	if strings.ToLower(remoteName) != remoteName {
-		return nil, fmt.Errorf("invalid reference format: repository name (%s) must be lowercase", remoteName)
+	if strings.ToLower(remote) != remote {
+		return nil, fmt.Errorf("invalid reference format: repository name (%s) must be lowercase", remote)
 	}
 
 	ref, err := Parse(domain + "/" + remainder)
@@ -55,41 +79,53 @@ func ParseNormalizedNamed(s string) (Named, error) {
 	return named, nil
 }
 
-// ParseDockerRef normalizes the image reference following the docker convention. This is added
-// mainly for backward compatibility.
-// The reference returned can only be either tagged or digested. For reference contains both tag
-// and digest, the function returns digested reference, e.g. docker.io/library/busybox:latest@
-// sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa will be returned as
-// docker.io/library/busybox@sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa.
+// namedTaggedDigested is a reference that has both a tag and a digest.
+type namedTaggedDigested interface {
+	NamedTagged
+	Digested
+}
+
+// ParseDockerRef normalizes the image reference following the docker convention,
+// which allows for references to contain both a tag and a digest. It returns a
+// reference that is either tagged or digested. For references containing both
+// a tag and a digest, it returns a digested reference. For example, the following
+// reference:
+//
+//	docker.io/library/busybox:latest@sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa
+//
+// Is returned as a digested reference (with the ":latest" tag removed):
+//
+//	docker.io/library/busybox@sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa
+//
+// References that are already "tagged" or "digested" are returned unmodified:
+//
+//	// Already a digested reference
+//	docker.io/library/busybox@sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa
+//
+//	// Already a named reference
+//	docker.io/library/busybox:latest
 func ParseDockerRef(ref string) (Named, error) {
 	named, err := ParseNormalizedNamed(ref)
 	if err != nil {
 		return nil, err
 	}
-	if _, ok := named.(NamedTagged); ok {
-		if canonical, ok := named.(Canonical); ok {
-			// The reference is both tagged and digested, only
-			// return digested.
-			newNamed, err := WithName(canonical.Name())
-			if err != nil {
-				return nil, err
-			}
-			newCanonical, err := WithDigest(newNamed, canonical.Digest())
-			if err != nil {
-				return nil, err
-			}
-			return newCanonical, nil
+	if canonical, ok := named.(namedTaggedDigested); ok {
+		// The reference is both tagged and digested; only return digested.
+		newNamed, err := WithName(canonical.Name())
+		if err != nil {
+			return nil, err
 		}
+		return WithDigest(newNamed, canonical.Digest())
 	}
 	return TagNameOnly(named), nil
 }
 
-// splitDockerDomain splits a repository name to domain and remotename string.
+// splitDockerDomain splits a repository name to domain and remote-name.
 // If no valid domain is found, the default domain is used. Repository name
 // needs to be already validated before.
 func splitDockerDomain(name string) (domain, remainder string) {
 	i := strings.IndexRune(name, '/')
-	if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost" && strings.ToLower(name[:i]) == name[:i]) {
+	if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != localhost && strings.ToLower(name[:i]) == name[:i]) {
 		domain, remainder = defaultDomain, name
 	} else {
 		domain, remainder = name[:i], name[i+1:]
@@ -98,7 +134,7 @@ func splitDockerDomain(name string) (domain, remainder string) {
 		domain = defaultDomain
 	}
 	if domain == defaultDomain && !strings.ContainsRune(remainder, '/') {
-		remainder = officialRepoName + "/" + remainder
+		remainder = officialRepoPrefix + remainder
 	}
 	return
 }
@@ -118,8 +154,15 @@ func familiarizeName(named namedRepository) repository {
 	if repo.domain == defaultDomain {
 		repo.domain = ""
 		// Handle official repositories which have the pattern "library/<official repo name>"
-		if split := strings.Split(repo.path, "/"); len(split) == 2 && split[0] == officialRepoName {
-			repo.path = split[1]
+		if strings.HasPrefix(repo.path, officialRepoPrefix) {
+			// TODO(thaJeztah): this check may be too strict, as it assumes the
+			//  "library/" namespace does not have nested namespaces. While this
+			//  is true (currently), technically it would be possible for Docker
+			//  Hub to use those (e.g. "library/distros/ubuntu:latest").
+			//  See https://github.com/distribution/distribution/pull/3769#issuecomment-1302031785.
+			if remainder := strings.TrimPrefix(repo.path, officialRepoPrefix); !strings.ContainsRune(remainder, '/') {
+				repo.path = remainder
+			}
 		}
 	}
 	return repo
@@ -179,20 +222,3 @@ 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)
-}

vendor/github.com/distribution/distribution/v3/reference/reference.go

@@ -3,15 +3,16 @@
 //
 // Grammar
 //
-// 	reference                       := name [ ":" tag ] [ "@" digest ]
-//	name                            := [domain '/'] path-component ['/' path-component]*
+//	reference                       := name [ ":" tag ] [ "@" digest ]
+//	name                            := [domain '/'] remote-name
 //	domain                          := host [':' port-number]
 //	host                            := domain-name | IPv4address | \[ IPv6address \]	; rfc3986 appendix-A
 //	domain-name                     := domain-component ['.' domain-component]*
 //	domain-component                := /([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])/
 //	port-number                     := /[0-9]+/
 //	path-component                  := alpha-numeric [separator alpha-numeric]*
-// 	alpha-numeric                   := /[a-z0-9]+/
+//	path (or "remote-name")         := path-component ['/' path-component]*
+//	alpha-numeric                   := /[a-z0-9]+/
 //	separator                       := /[_.]|__|[-]*/
 //
 //	tag                             := /[\w][\w.-]{0,127}/
@@ -23,7 +24,6 @@
 //	digest-hex                      := /[0-9a-fA-F]{32,}/ ; At least 128 bit digest value
 //
 //	identifier                      := /[a-f0-9]{64}/
-//	short-identifier                := /[a-f0-9]{6,64}/
 package reference
 
 import (
@@ -147,7 +147,7 @@ type namedRepository interface {
 	Path() string
 }
 
-// Domain returns the domain part of the Named reference
+// Domain returns the domain part of the [Named] reference.
 func Domain(named Named) string {
 	if r, ok := named.(namedRepository); ok {
 		return r.Domain()
@@ -156,7 +156,7 @@ func Domain(named Named) string {
 	return domain
 }
 
-// Path returns the name without the domain part of the Named reference
+// Path returns the name without the domain part of the [Named] reference.
 func Path(named Named) (name string) {
 	if r, ok := named.(namedRepository); ok {
 		return r.Path()
@@ -177,7 +177,8 @@ func splitDomain(name string) (string, string) {
 // hostname and name string. If no valid hostname is
 // found, the hostname is empty and the full value
 // is returned as name
-// DEPRECATED: Use Domain or Path
+//
+// Deprecated: Use [Domain] or [Path].
 func SplitHostname(named Named) (string, string) {
 	if r, ok := named.(namedRepository); ok {
 		return r.Domain(), r.Path()
@@ -187,7 +188,6 @@ func SplitHostname(named Named) (string, string) {
 
 // Parse parses s and returns a syntactically valid Reference.
 // If an error was encountered it is returned, along with a nil Reference.
-// NOTE: Parse will not handle short digests.
 func Parse(s string) (Reference, error) {
 	matches := ReferenceRegexp.FindStringSubmatch(s)
 	if matches == nil {
@@ -239,7 +239,6 @@ func Parse(s string) (Reference, error) {
 // the Named interface. The reference must have a name and be in the canonical
 // form, otherwise an error is returned.
 // If an error was encountered it is returned, along with a nil Reference.
-// NOTE: ParseNamed will not handle short digests.
 func ParseNamed(s string) (Named, error) {
 	named, err := ParseNormalizedNamed(s)
 	if err != nil {
@@ -322,11 +321,13 @@ func WithDigest(name Named, digest digest.Digest) (Canonical, error) {
 
 // TrimNamed removes any tag or digest from the named reference.
 func TrimNamed(ref Named) Named {
-	domain, path := SplitHostname(ref)
-	return repository{
-		domain: domain,
-		path:   path,
+	repo := repository{}
+	if r, ok := ref.(namedRepository); ok {
+		repo.domain, repo.path = r.Domain(), r.Path()
+	} else {
+		repo.domain, repo.path = splitDomain(ref.Name())
 	}
+	return repo
 }
 
 func getBestReferenceType(ref reference) Reference {

vendor/github.com/distribution/distribution/v3/reference/regexp.go

@@ -1,48 +1,102 @@
 package reference
 
-import "regexp"
+import (
+	"regexp"
+	"strings"
+)
 
-var (
-	// alphaNumeric defines the alpha numeric atom, typically a
+// DigestRegexp matches well-formed digests, including algorithm (e.g. "sha256:<encoded>").
+var DigestRegexp = regexp.MustCompile(digestPat)
+
+// DomainRegexp matches hostname or IP-addresses, optionally including a port
+// number. It defines the structure of potential domain components that may be
+// part of image names. This is purposely a subset of what is allowed by DNS to
+// ensure backwards compatibility with Docker image names. It may be a subset of
+// DNS domain name, an IPv4 address in decimal format, or an IPv6 address between
+// square brackets (excluding zone identifiers as defined by [RFC 6874] or special
+// addresses such as IPv4-Mapped).
+//
+// [RFC 6874]: https://www.rfc-editor.org/rfc/rfc6874.
+var DomainRegexp = regexp.MustCompile(domainAndPort)
+
+// IdentifierRegexp is the format for string identifier used as a
+// content addressable identifier using sha256. These identifiers
+// are like digests without the algorithm, since sha256 is used.
+var IdentifierRegexp = regexp.MustCompile(identifier)
+
+// NameRegexp is the format for the name component of references, including
+// an optional domain and port, but without tag or digest suffix.
+var NameRegexp = regexp.MustCompile(namePat)
+
+// ReferenceRegexp is the full supported format of a reference. The regexp
+// is anchored and has capturing groups for name, tag, and digest
+// components.
+var ReferenceRegexp = regexp.MustCompile(referencePat)
+
+// TagRegexp matches valid tag names. From [docker/docker:graph/tags.go].
+//
+// [docker/docker:graph/tags.go]: https://github.com/moby/moby/blob/v1.6.0/graph/tags.go#L26-L28
+var TagRegexp = regexp.MustCompile(tag)
+
+const (
+	// alphanumeric defines the alphanumeric atom, typically a
 	// component of names. This only allows lower case characters and digits.
-	alphaNumeric = `[a-z0-9]+`
+	alphanumeric = `[a-z0-9]+`
 
 	// separator defines the separators allowed to be embedded in name
-	// components. This allow one period, one or two underscore and multiple
+	// components. This allows one period, one or two underscore and multiple
 	// dashes. Repeated dashes and underscores are intentionally treated
 	// differently. In order to support valid hostnames as name components,
 	// supporting repeated dash was added. Additionally double underscore is
 	// now allowed as a separator to loosen the restriction for previously
 	// supported names.
-	separator = `(?:[._]|__|[-]*)`
+	separator = `(?:[._]|__|[-]+)`
 
-	// nameComponent restricts registry path component names to start
-	// with at least one letter or number, with following parts able to be
-	// separated by one period, one or two underscore and multiple dashes.
-	nameComponent = expression(
-		alphaNumeric,
-		optional(repeated(separator, alphaNumeric)))
+	// localhost is treated as a special value for domain-name. Any other
+	// domain-name without a "." or a ":port" are considered a path component.
+	localhost = `localhost`
 
 	// domainNameComponent restricts the registry domain component of a
 	// repository name to start with a component as defined by DomainRegexp.
 	domainNameComponent = `(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])`
 
+	// optionalPort matches an optional port-number including the port separator
+	// (e.g. ":80").
+	optionalPort = `(?::[0-9]+)?`
+
+	// tag matches valid tag names. From docker/docker:graph/tags.go.
+	tag = `[\w][\w.-]{0,127}`
+
+	// digestPat matches well-formed digests, including algorithm (e.g. "sha256:<encoded>").
+	//
+	// TODO(thaJeztah): this should follow the same rules as https://pkg.go.dev/github.com/opencontainers/go-digest@v1.0.0#DigestRegexp
+	// so that go-digest defines the canonical format. Note that the go-digest is
+	// more relaxed:
+	//   - it allows multiple algorithms (e.g. "sha256+b64:<encoded>") to allow
+	//     future expansion of supported algorithms.
+	//   - it allows the "<encoded>" value to use urlsafe base64 encoding as defined
+	//     in [rfc4648, section 5].
+	//
+	// [rfc4648, section 5]: https://www.rfc-editor.org/rfc/rfc4648#section-5.
+	digestPat = `[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`
+
+	// identifier is the format for a content addressable identifier using sha256.
+	// These identifiers are like digests without the algorithm, since sha256 is used.
+	identifier = `([a-f0-9]{64})`
+
 	// ipv6address are enclosed between square brackets and may be represented
 	// in many ways, see rfc5952. Only IPv6 in compressed or uncompressed format
 	// are allowed, IPv6 zone identifiers (rfc6874) or Special addresses such as
 	// IPv4-Mapped are deliberately excluded.
-	ipv6address = expression(
-		literal(`[`), `(?:[a-fA-F0-9:]+)`, literal(`]`),
-	)
+	ipv6address = `\[(?:[a-fA-F0-9:]+)\]`
+)
 
+var (
 	// domainName defines the structure of potential domain components
 	// that may be part of image names. This is purposely a subset of what is
 	// allowed by DNS to ensure backwards compatibility with Docker image
 	// names. This includes IPv4 addresses on decimal format.
-	domainName = expression(
-		domainNameComponent,
-		optional(repeated(literal(`.`), domainNameComponent)),
-	)
+	domainName = domainNameComponent + anyTimes(`\.`+domainNameComponent)
 
 	// host defines the structure of potential domains based on the URI
 	// Host subcomponent on rfc3986. It may be a subset of DNS domain name,
@@ -53,129 +107,57 @@ var (
 
 	// allowed by the URI Host subcomponent on rfc3986 to ensure backwards
 	// compatibility with Docker image names.
-	domain = expression(
-		host,
-		optional(literal(`:`), `[0-9]+`))
+	domainAndPort = host + optionalPort
 
-	// DomainRegexp defines the structure of potential domain components
-	// that may be part of image names. This is purposely a subset of what is
-	// allowed by DNS to ensure backwards compatibility with Docker image
-	// names.
-	DomainRegexp = regexp.MustCompile(domain)
-
-	tag = `[\w][\w.-]{0,127}`
-	// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
-	TagRegexp = regexp.MustCompile(tag)
-
-	anchoredTag = anchored(tag)
 	// anchoredTagRegexp matches valid tag names, anchored at the start and
 	// end of the matched string.
-	anchoredTagRegexp = regexp.MustCompile(anchoredTag)
+	anchoredTagRegexp = regexp.MustCompile(anchored(tag))
 
-	digestPat = `[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`
-	// DigestRegexp matches valid digests.
-	DigestRegexp = regexp.MustCompile(digestPat)
-
-	anchoredDigest = anchored(digestPat)
 	// anchoredDigestRegexp matches valid digests, anchored at the start and
 	// end of the matched string.
-	anchoredDigestRegexp = regexp.MustCompile(anchoredDigest)
+	anchoredDigestRegexp = regexp.MustCompile(anchored(digestPat))
 
-	namePat = expression(
-		optional(domain, literal(`/`)),
-		nameComponent,
-		optional(repeated(literal(`/`), nameComponent)))
-	// NameRegexp is the format for the name component of references. The
-	// regexp has capturing groups for the domain and name part omitting
-	// the separating forward slash from either.
-	NameRegexp = regexp.MustCompile(namePat)
+	// pathComponent restricts path-components to start with an alphanumeric
+	// character, with following parts able to be separated by a separator
+	// (one period, one or two underscore and multiple dashes).
+	pathComponent = alphanumeric + anyTimes(separator+alphanumeric)
+
+	// remoteName matches the remote-name of a repository. It consists of one
+	// or more forward slash (/) delimited path-components:
+	//
+	//	pathComponent[[/pathComponent] ...] // e.g., "library/ubuntu"
+	remoteName = pathComponent + anyTimes(`/`+pathComponent)
+	namePat    = optional(domainAndPort+`/`) + remoteName
 
-	anchoredName = anchored(
-		optional(capture(domain), literal(`/`)),
-		capture(nameComponent,
-			optional(repeated(literal(`/`), nameComponent))))
 	// anchoredNameRegexp is used to parse a name value, capturing the
 	// domain and trailing components.
-	anchoredNameRegexp = regexp.MustCompile(anchoredName)
+	anchoredNameRegexp = regexp.MustCompile(anchored(optional(capture(domainAndPort), `/`), capture(remoteName)))
 
-	referencePat = anchored(capture(namePat),
-		optional(literal(":"), capture(tag)),
-		optional(literal("@"), capture(digestPat)))
-	// ReferenceRegexp is the full supported format of a reference. The regexp
-	// is anchored and has capturing groups for name, tag, and digest
-	// components.
-	ReferenceRegexp = regexp.MustCompile(referencePat)
+	referencePat = anchored(capture(namePat), optional(`:`, capture(tag)), optional(`@`, capture(digestPat)))
 
-	identifier = `([a-f0-9]{64})`
-	// IdentifierRegexp is the format for string identifier used as a
-	// content addressable identifier using sha256. These identifiers
-	// 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)
+	anchoredIdentifierRegexp = regexp.MustCompile(anchored(identifier))
 )
 
-// literal compiles s into a literal regular expression, escaping any regexp
-// reserved characters.
-func literal(s string) string {
-	re := regexp.MustCompile(regexp.QuoteMeta(s))
-
-	if _, complete := re.LiteralPrefix(); !complete {
-		panic("must be a literal")
-	}
-
-	return re.String()
-}
-
-// expression defines a full expression, where each regular expression must
-// follow the previous.
-func expression(res ...string) string {
-	var s string
-	for _, re := range res {
-		s += re
-	}
-
-	return s
-}
-
 // optional wraps the expression in a non-capturing group and makes the
 // production optional.
 func optional(res ...string) string {
-	return group(expression(res...)) + `?`
+	return `(?:` + strings.Join(res, "") + `)?`
 }
 
-// repeated wraps the regexp in a non-capturing group to get one or more
-// matches.
-func repeated(res ...string) string {
-	return group(expression(res...)) + `+`
-}
-
-// group wraps the regexp in a non-capturing group.
-func group(res ...string) string {
-	return `(?:` + expression(res...) + `)`
+// anyTimes wraps the expression in a non-capturing group that can occur
+// any number of times.
+func anyTimes(res ...string) string {
+	return `(?:` + strings.Join(res, "") + `)*`
 }
 
 // capture wraps the expression in a capturing group.
 func capture(res ...string) string {
-	return `(` + expression(res...) + `)`
+	return `(` + strings.Join(res, "") + `)`
 }
 
 // anchored anchors the regular expression by adding start and end delimiters.
 func anchored(res ...string) string {
-	return `^` + expression(res...) + `$`
+	return `^` + strings.Join(res, "") + `$`
 }

vendor/github.com/distribution/distribution/v3/reference/sort.go

@@ -0,0 +1,75 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package reference
+
+import (
+	"sort"
+)
+
+// Sort sorts string references preferring higher information references.
+//
+// The precedence is as follows:
+//
+//  1. [Named] + [Tagged] + [Digested] (e.g., "docker.io/library/busybox:latest@sha256:<digest>")
+//  2. [Named] + [Tagged]              (e.g., "docker.io/library/busybox:latest")
+//  3. [Named] + [Digested]            (e.g., "docker.io/library/busybo@sha256:<digest>")
+//  4. [Named]                         (e.g., "docker.io/library/busybox")
+//  5. [Digested]                      (e.g., "docker.io@sha256:<digest>")
+//  6. Parse error
+func Sort(references []string) []string {
+	var prefs []Reference
+	var bad []string
+
+	for _, ref := range references {
+		pref, err := ParseAnyReference(ref)
+		if err != nil {
+			bad = append(bad, ref)
+		} else {
+			prefs = append(prefs, pref)
+		}
+	}
+	sort.Slice(prefs, func(a, b int) bool {
+		ar := refRank(prefs[a])
+		br := refRank(prefs[b])
+		if ar == br {
+			return prefs[a].String() < prefs[b].String()
+		}
+		return ar < br
+	})
+	sort.Strings(bad)
+	var refs []string
+	for _, pref := range prefs {
+		refs = append(refs, pref.String())
+	}
+	return append(refs, bad...)
+}
+
+func refRank(ref Reference) uint8 {
+	if _, ok := ref.(Named); ok {
+		if _, ok = ref.(Tagged); ok {
+			if _, ok = ref.(Digested); ok {
+				return 1
+			}
+			return 2
+		}
+		if _, ok = ref.(Digested); ok {
+			return 3
+		}
+		return 4
+	}
+	return 5
+}