fix: provide a Versions method on VersionIndex (#311)

Provides a Versions method on the VersionIndex type which returns a copy
of the VersionSlice used to build the index.

This is a pre-requisite to upgrade the vervet version of
vervet-underground.

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/urfave/cli/v2 v2.25.7
 	github.com/vmware-labs/yaml-jsonpath v0.3.2
 	go.uber.org/multierr v1.11.0
+	golang.org/x/exp v0.0.0-20231006140011-7918f672742d
 	gopkg.in/yaml.v3 v3.0.1
 )
 

go.sum

@@ -211,6 +211,8 @@ golang.org/x/crypto v0.3.1-0.20221117191849-2c476679df9a/go.mod h1:hebNnKkNXi2Uz
 golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
 golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
 golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=

resource.go

@@ -6,11 +6,11 @@ import (
 	"errors"
 	"fmt"
 	"path/filepath"
-	"sort"
 	"time"
 
 	"github.com/bmatcuk/doublestar/v4"
 	"github.com/getkin/kin-openapi/openapi3"
+	"golang.org/x/exp/maps"
 )
 
 const (
@@ -125,14 +125,7 @@ func (rv *ResourceVersions) Name() string {
 
 // Versions returns each Version defined for this resource.
 func (rv *ResourceVersions) Versions() VersionSlice {
-	result := make(VersionSlice, len(rv.versions))
-	i := 0
-	for v := range rv.versions {
-		result[i] = v
-		i++
-	}
-	sort.Sort(result)
-	return result
+	return rv.index.Versions()
 }
 
 // ErrNoMatchingVersion indicates the requested version cannot be satisfied by
@@ -275,7 +268,7 @@ func LoadResourceVersionsFileset(specYamls []string) (*ResourceVersions, error)
 			}
 		}
 	}
-	resourceVersions.index = NewVersionIndex((resourceVersions.Versions()))
+	resourceVersions.index = NewVersionIndex(maps.Keys(resourceVersions.versions))
 	return &resourceVersions, nil
 }
 

spec.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/bmatcuk/doublestar/v4"
 	"github.com/getkin/kin-openapi/openapi3"
+	"golang.org/x/exp/maps"
 )
 
 // SpecGlobPattern defines the expected directory structure for the versioned
@@ -19,7 +20,6 @@ const SpecGlobPattern = "**/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]/spec.yaml
 
 // SpecVersions stores a collection of versioned OpenAPI specs.
 type SpecVersions struct {
-	versions  VersionSlice
 	index     VersionIndex
 	documents map[Version]*openapi3.T
 }
@@ -68,7 +68,7 @@ func LoadSpecVersionsFileset(epPaths []string) (*SpecVersions, error) {
 // Versions returns the distinct API versions in this collection of OpenAPI
 // documents.
 func (sv *SpecVersions) Versions() VersionSlice {
-	return sv.versions
+	return sv.index.Versions()
 }
 
 // At returns the OpenAPI document that matches the given version. If the
@@ -104,7 +104,7 @@ func (sv *SpecVersions) resolveOperations() {
 	}
 	type operationVersionMap map[operationKey]operationVersion
 	activeOpsByStability := map[Stability]operationVersionMap{}
-	for _, v := range sv.versions {
+	for _, v := range sv.index.versions {
 		doc := sv.documents[v]
 		currentActiveOps, ok := activeOpsByStability[v.Stability]
 		if !ok {
@@ -245,14 +245,8 @@ func newSpecVersions(specs resourceVersionsSlice) (*SpecVersions, error) {
 			documentVersions[v] = doc
 		}
 	}
-	versions = VersionSlice{}
-	for v := range documentVersions {
-		versions = append(versions, v)
-	}
-	sort.Sort(versions)
 	sv := &SpecVersions{
-		versions:  versions,
-		index:     NewVersionIndex(versions),
+		index:     NewVersionIndex(maps.Keys(documentVersions)),
 		documents: documentVersions,
 	}
 	sv.resolveOperations()

version.go

@@ -238,7 +238,8 @@ type VersionSlice []Version
 // VersionIndex provides a search over versions, resolving which version is in
 // effect for a given date and stability level.
 type VersionIndex struct {
-	versions []effectiveVersion
+	effectiveVersions []effectiveVersion
+	versions          VersionSlice
 }
 
 type effectiveVersion struct {
@@ -250,38 +251,46 @@ type effectiveVersion struct {
 // VersionSlice will be sorted.
 func NewVersionIndex(vs VersionSlice) (vi VersionIndex) {
 	sort.Sort(vs)
+	vi.versions = make(VersionSlice, len(vs))
+	copy(vi.versions, vs)
+
 	evIndex := -1
 	currentStabilities := [numStabilityLevels]time.Time{}
-	for i := range vs {
-		if evIndex == -1 || !vi.versions[evIndex].date.Equal(vs[i].Date) {
-			vi.versions = append(vi.versions, effectiveVersion{
-				date:        vs[i].Date,
+	for i := range vi.versions {
+		if evIndex == -1 || !vi.effectiveVersions[evIndex].date.Equal(vi.versions[i].Date) {
+			vi.effectiveVersions = append(vi.effectiveVersions, effectiveVersion{
+				date:        vi.versions[i].Date,
 				stabilities: currentStabilities,
 			})
 			evIndex++
 		}
-		vi.versions[evIndex].stabilities[vs[i].Stability] = vs[i].Date
-		currentStabilities[vs[i].Stability] = vs[i].Date
+		vi.effectiveVersions[evIndex].stabilities[vi.versions[i].Stability] = vi.versions[i].Date
+		currentStabilities[vi.versions[i].Stability] = vi.versions[i].Date
 	}
 	return vi
 }
 
-// resolveIndex performs a binary search on the stability versions in effect on
-// the query date.
-func (vi *VersionIndex) resolveIndex(query time.Time) (int, error) {
-	if len(vi.versions) == 0 || vi.versions[0].date.After(query) {
-		return -1, ErrNoMatchingVersion
+// Deprecates returns the version that deprecates the given version in the
+// slice.
+func (vi *VersionIndex) Deprecates(q Version) (Version, bool) {
+	match, err := vi.resolveIndex(q.Date)
+	if err == ErrNoMatchingVersion {
+		return Version{}, false
 	}
-	lower, curr, upper := 0, len(vi.versions)/2, len(vi.versions)
-	for lower < upper-1 {
-		if vi.versions[curr].date.After(query) {
-			upper = curr
-		} else {
-			lower = curr
+	if err != nil {
+		panic(err)
+	}
+	for i := match + 1; i < len(vi.effectiveVersions); i++ {
+		for stab := q.Stability; stab < numStabilityLevels; stab++ {
+			if stabDate := vi.effectiveVersions[i].stabilities[stab]; stabDate.After(q.Date) {
+				return Version{
+					Date:      vi.effectiveVersions[i].date,
+					Stability: stab,
+				}, true
+			}
 		}
-		curr = lower + (upper-lower)/2
 	}
-	return lower, nil
+	return Version{}, false
 }
 
 // Resolve returns the released version effective on the query version date at
@@ -295,13 +304,38 @@ func (vi *VersionIndex) Resolve(query Version) (Version, error) {
 		return Version{}, err
 	}
 	for stab := query.Stability; stab < numStabilityLevels; stab++ {
-		if stabDate := vi.versions[i].stabilities[stab]; !stabDate.IsZero() {
+		if stabDate := vi.effectiveVersions[i].stabilities[stab]; !stabDate.IsZero() {
 			return Version{Date: stabDate, Stability: stab}, nil
 		}
 	}
 	return Version{}, ErrNoMatchingVersion
 }
 
+// Versions returns each Version defined.
+func (vi *VersionIndex) Versions() VersionSlice {
+	vs := make(VersionSlice, len(vi.versions))
+	copy(vs, vi.versions)
+	return vs
+}
+
+// resolveIndex performs a binary search on the stability versions in effect on
+// the query date.
+func (vi *VersionIndex) resolveIndex(query time.Time) (int, error) {
+	if len(vi.effectiveVersions) == 0 || vi.effectiveVersions[0].date.After(query) {
+		return -1, ErrNoMatchingVersion
+	}
+	lower, curr, upper := 0, len(vi.effectiveVersions)/2, len(vi.effectiveVersions)
+	for lower < upper-1 {
+		if vi.effectiveVersions[curr].date.After(query) {
+			upper = curr
+		} else {
+			lower = curr
+		}
+		curr = lower + (upper-lower)/2
+	}
+	return lower, nil
+}
+
 // resolveForBuild returns the most stable version effective on the query
 // version date with respect to the given version stability. Returns
 // ErrNoMatchingVersion if no version matches.
@@ -316,7 +350,7 @@ func (vi *VersionIndex) resolveForBuild(query Version) (Version, error) {
 	var matchDate time.Time
 	var matchStab Stability
 	for stab := query.Stability; stab < numStabilityLevels; stab++ {
-		stabDate := vi.versions[i].stabilities[stab]
+		stabDate := vi.effectiveVersions[i].stabilities[stab]
 		if !stabDate.IsZero() && !stabDate.Before(matchDate) && !stabDate.After(query.Date) {
 			matchDate, matchStab = stabDate, stab
 		}
@@ -327,29 +361,6 @@ func (vi *VersionIndex) resolveForBuild(query Version) (Version, error) {
 	return Version{Date: matchDate, Stability: matchStab}, nil
 }
 
-// Deprecates returns the version that deprecates the given version in the
-// slice.
-func (vi *VersionIndex) Deprecates(q Version) (Version, bool) {
-	match, err := vi.resolveIndex(q.Date)
-	if err == ErrNoMatchingVersion {
-		return Version{}, false
-	}
-	if err != nil {
-		panic(err)
-	}
-	for i := match + 1; i < len(vi.versions); i++ {
-		for stab := q.Stability; stab < numStabilityLevels; stab++ {
-			if stabDate := vi.versions[i].stabilities[stab]; stabDate.After(q.Date) {
-				return Version{
-					Date:      vi.versions[i].date,
-					Stability: stab,
-				}, true
-			}
-		}
-	}
-	return Version{}, false
-}
-
 // Len implements sort.Interface.
 func (vs VersionSlice) Len() int { return len(vs) }
 

versionware/example/go.mod

@@ -35,6 +35,7 @@ require (
 	github.com/prometheus/procfs v0.12.0 // indirect
 	github.com/rogpeppe/go-internal v1.11.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect
 	golang.org/x/sys v0.13.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect

versionware/example/go.sum

@@ -72,6 +72,8 @@ github.com/ugorji/go/codec v1.2.11 h1:BMaWp1Bb6fHwEtbplGBGJ498wD+LKlNSl25MjdZY4d
 github.com/ugorji/go/codec v1.2.11/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZgYf6w6lg=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
 go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
 golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
 golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=