Version prefix matters when sorting tags names

Make sure that 'v' prefix is taken into account.

Sort identical tag names with 'v' prefix at the end.

Signed-off-by: Michal Minář <miminar@redhat.com>

pkg/image/apis/image/helper.go

@@ -856,6 +856,7 @@ type prioritizedTag struct {
 	tag      string
 	priority tagPriority
 	semver   semver.Version
+	prefix   string
 }
 
 func prioritizeTag(tag string) prioritizedTag {
@@ -866,14 +867,20 @@ func prioritizeTag(tag string) prioritizedTag {
 		}
 	}
 
-	short := strings.TrimLeft(tag, "v")
+	short := tag
+	prefix := ""
+	if strings.HasPrefix(tag, "v") {
+		prefix = "v"
+		short = tag[1:]
+	}
 
 	// 5.1.3
 	if v, err := semver.Parse(short); err == nil {
 		return prioritizedTag{
 			tag:      tag,
 			priority: tagPriorityFull,
 			semver:   v,
+			prefix:   prefix,
 		}
 	}
 
@@ -884,6 +891,7 @@ func prioritizeTag(tag string) prioritizedTag {
 				tag:      tag,
 				priority: tagPriorityMinor,
 				semver:   v,
+				prefix:   prefix,
 			}
 		}
 	}
@@ -895,6 +903,7 @@ func prioritizeTag(tag string) prioritizedTag {
 				tag:      tag,
 				priority: tagPriorityMinor,
 				semver:   v,
+				prefix:   prefix,
 			}
 		}
 	}
@@ -903,6 +912,7 @@ func prioritizeTag(tag string) prioritizedTag {
 	return prioritizedTag{
 		tag:      tag,
 		priority: tagPriorityOther,
+		prefix:   prefix,
 	}
 }
 
@@ -920,7 +930,10 @@ func (t prioritizedTags) Less(i, j int) bool {
 	}
 
 	cmp := t[i].semver.Compare(t[j].semver)
-	return cmp > 0 // the newer tag has a higher priority
+	if cmp > 0 { // the newer tag has a higher priority
+		return true
+	}
+	return t[i].prefix < t[j].prefix
 }
 
 // PrioritizeTags orders a set of image tags with a few conventions:

pkg/image/apis/image/helper_test.go

@@ -1161,7 +1161,7 @@ func TestPrioritizeTags(t *testing.T) {
 	}{
 		{
 			tags:     []string{"other", "latest", "v5.5", "5.2.3", "v5.3.6-bother", "5.3.6-abba", "5.6"},
-			expected: []string{"latest", "5.6", "v5.5", "v5.3.6-bother", "5.3.6-abba", "5.2.3", "other"},
+			expected: []string{"latest", "5.6", "v5.5", "5.3.6-abba", "v5.3.6-bother", "5.2.3", "other"},
 		},
 		{
 			tags:     []string{"1.1-beta1", "1.2-rc1", "1.1-rc1", "1.1-beta2", "1.2-beta1", "1.2-alpha1", "1.2-beta4", "latest"},
@@ -1171,6 +1171,10 @@ func TestPrioritizeTags(t *testing.T) {
 			tags:     []string{"7.1", "v7.1", "7.1.0"},
 			expected: []string{"7.1", "v7.1", "7.1.0"},
 		},
+		{
+			tags:     []string{"7.1.0", "v7.1", "7.1"},
+			expected: []string{"7.1", "v7.1", "7.1.0"},
+		},
 	}
 
 	for _, tc := range tests {