Improve sorting Github release tags to handle empty string; no version

github.go

@@ -10,7 +10,6 @@ import (
 	"path/filepath"
 	"regexp"
 	"runtime"
-	"sort"
 	"strings"
 )
 
@@ -132,21 +131,21 @@ func (g GithubReleases) MatchTagFromPartialVersion(pv string) (tag string, found
 			tags[i] = j.TagName
 		}
 	}
-	sort.Strings(tags)
+	sortedTags := sortVersions(tags)
 	LCPV := strings.ToLower(pv)
 	// Iterate the Github release tags backwards.
-	for i := len(tags) - 1; i >= 0; i-- {
-		LCThisTag := strings.ToLower(tags[i])
+	for i := len(sortedTags) - 1; i >= 0; i-- {
+		LCThisTag := strings.ToLower(sortedTags[i])
 		if strings.HasPrefix(LCThisTag, LCPV) || strings.HasPrefix(LCThisTag, "v"+LCPV) {
-			debugLog.Printf("matched tag %q for partial version %s\n", tags[i], pv)
-			return tags[i], true
+			debugLog.Printf("matched tag %q for partial version %s\n", sortedTags[i], pv)
+			return sortedTags[i], true
 		}
 	}
 	// Try matching with extraneous text removed from the beginning of the tag,
 	// like tags that include the repo or release name.
 	var stripPrefixRE *regexp.Regexp = regexp.MustCompile(`^[a-zA-Z-_]+(v?\d+\..*)`)
-	for i := len(tags) - 1; i >= 0; i-- {
-		LCThisTag := strings.ToLower(tags[i])
+	for i := len(sortedTags) - 1; i >= 0; i-- {
+		LCThisTag := strings.ToLower(sortedTags[i])
 		strippedMatches := stripPrefixRE.FindStringSubmatch(LCThisTag)
 		if strippedMatches == nil || len(strippedMatches) < 2 {
 			debugLog.Printf("cannot strip extraneous text from tag %q\n", LCThisTag)
@@ -155,8 +154,8 @@ func (g GithubReleases) MatchTagFromPartialVersion(pv string) (tag string, found
 		strippedTag := strippedMatches[1]
 		debugLog.Printf("the stripped tag is %q", strippedTag)
 		if strings.HasPrefix(strippedTag, LCPV) || strings.HasPrefix(strippedTag, "v"+LCPV) {
-			debugLog.Printf("matched tag %q after stripping prefix %q, for partial version %s\n", tags[i], strippedTag, pv)
-			return tags[i], true
+			debugLog.Printf("matched tag %q after stripping prefix %q, for partial version %s\n", sortedTags[i], strippedTag, pv)
+			return sortedTags[i], true
 		}
 	}
 	debugLog.Printf("no partial match for %s\n", pv)

github_test.go

@@ -25,6 +25,10 @@ func TestGithubMatchTagFromPartialVersion(t *testing.T) {
 			ReleaseName: "1.0.2",
 			TagName:     "1.0.2",
 		},
+		{
+			ReleaseName: "release with no version",
+			TagName:     "",
+		},
 		{
 			ReleaseName: "1.0.3-rc1",
 			TagName:     "1.0.3-rc1",

toolmanaged.go

@@ -8,8 +8,6 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
-
-	hashicorpversion "github.com/hashicorp/go-version"
 )
 
 // managedTool represents a tool that JKL has already installed.
@@ -138,21 +136,8 @@ func (t managedTool) listInstalledVersions() (versions []string, found bool, err
 	if !found {
 		return nil, false, nil
 	}
-	sortedVersions := make([]*hashicorpversion.Version, len(versions))
-	for i, v := range versions {
-		hv, err := hashicorpversion.NewVersion(v)
-		if err != nil {
-			debugLog.Printf("using string-sort while listing installed versions - the version %q can't be converted to a version, probably because it starts with extraneous text", v)
-			sort.Strings(versions)
-			return versions, true, nil
-		}
-		sortedVersions[i] = hv
-	}
-	sort.Sort(hashicorpversion.Collection(sortedVersions))
-	for i, v := range sortedVersions { // reorder the original version strings by hashicorpversion.Version order
-		versions[i] = v.Original()
-	}
-	return versions, true, nil
+	sortedVersions := sortVersions(versions)
+	return sortedVersions, true, nil
 }
 
 // latestInstalledVersion returns the latest version number that is installed

util.go

@@ -7,7 +7,10 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
+
+	hashicorpversion "github.com/hashicorp/go-version"
 )
 
 // stringContainsOneOfLowerCase reports the first substring contained in s, returning
@@ -215,3 +218,30 @@ func getAliasesForOperatingSystem(OS string) []string {
 	}
 	return OSAliases[strings.ToLower(OS)]
 }
+
+// SortVersions returns the slice of strings sorted as semver version numbers.
+// Any empty strings are replaced with version 0.0.0 before being sorted, to
+// retain the size of the slice.
+func sortVersions(versions []string) []string {
+	debugLog.Printf("sorting %d versions: %v", len(versions), versions)
+	sortedVersions := make([]*hashicorpversion.Version, len(versions))
+	for i, v := range versions {
+		if v == "" {
+			debugLog.Printf("WARNING: the version at index %d is an empty string, using 0.0.0 instead", i)
+			v = "0.0.0"
+		}
+		hv, err := hashicorpversion.NewVersion(v)
+		if err != nil {
+			debugLog.Printf("using string-sort while listing installed versions - the version %q can't be converted to a version, probably because it starts with extraneous text: %v", v, err)
+			sort.Strings(versions)
+			return versions
+		}
+		sortedVersions[i] = hv
+	}
+	sort.Sort(hashicorpversion.Collection(sortedVersions))
+	for i, v := range sortedVersions { // reorder the original version strings by hashicorpversion.Version order
+		versions[i] = v.Original()
+	}
+	debugLog.Printf("sorted versions are: %v", versions)
+	return versions
+}