Add support for setting new tag while preserving the current name

- As well as setting new name while keeping the tag

Issue: #3487

kustomize/internal/commands/edit/set/setimage.go

@@ -20,7 +20,9 @@ type setImageOptions struct {
 	imageMap map[string]types.Image
 }
 
-var pattern = regexp.MustCompile("^(.*):([a-zA-Z0-9._-]*)$")
+var pattern = regexp.MustCompile("^(.*):([a-zA-Z0-9._-]*|\\*)$")
+
+var preserveSeparator = "*"
 
 // errors
 
@@ -74,7 +76,8 @@ images:
 to the kustomization file if it doesn't exist,
 and overwrite the previous ones if the image name exists.
 
-The image tag can only contain alphanumeric, '.', '_' and '-'.
+The image tag can only contain alphanumeric, '.', '_' and '-'. Passing * (asterisk) either in the new name 
+or in new tag will preserve the appropriate values from the kustomization file.
 `,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			err := o.Validate(args)
@@ -125,7 +128,20 @@ func (o *setImageOptions) RunSetImage(fSys filesys.FileSystem) error {
 
 	// append only new images from kustomize file
 	for _, im := range m.Images {
-		if _, ok := o.imageMap[im.Name]; ok {
+		if argIm, ok := o.imageMap[im.Name]; ok {
+
+			// Reuse the existing new name when asterisk new name is passed
+			if argIm.NewName == preserveSeparator {
+				argIm = replaceNewName(argIm, im.NewName)
+			}
+
+			// Reuse the existing new tag when asterisk new tag is passed
+			if argIm.NewTag == preserveSeparator {
+				argIm = replaceNewTag(argIm, im.NewTag)
+			}
+
+			o.imageMap[im.Name] = argIm
+
 			continue
 		}
 
@@ -134,6 +150,15 @@ func (o *setImageOptions) RunSetImage(fSys filesys.FileSystem) error {
 
 	var images []types.Image
 	for _, v := range o.imageMap {
+
+		if v.NewName == preserveSeparator {
+			v = replaceNewName(v, "")
+		}
+
+		if v.NewTag == preserveSeparator {
+			v = replaceNewTag(v, "")
+		}
+
 		images = append(images, v)
 	}
 
@@ -145,6 +170,24 @@ func (o *setImageOptions) RunSetImage(fSys filesys.FileSystem) error {
 	return mf.Write(m)
 }
 
+func replaceNewName(image types.Image, newName string) types.Image {
+	return types.Image{
+		Name:    image.Name,
+		NewName: newName,
+		NewTag:  image.NewTag,
+		Digest:  image.Digest,
+	}
+}
+
+func replaceNewTag(image types.Image, newTag string) types.Image {
+	return types.Image{
+		Name:    image.Name,
+		NewName: image.NewName,
+		NewTag:  newTag,
+		Digest:  image.Digest,
+	}
+}
+
 func parse(arg string) (types.Image, error) {
 
 	// matches if there is an image name to overwrite

kustomize/internal/commands/edit/set/setimage_test.go

@@ -251,6 +251,104 @@ func TestSetImage(t *testing.T) {
 				err: errImageInvalidArgs,
 			},
 		},
+		{
+			description: "override new tag but keep new name",
+			given: given{
+				args: []string{"image1=*:v1"},
+				infileImages: []string{
+					"images:",
+					"- name: image1",
+					"  newName: foo.bar.foo:8800/foo/image1",
+					"  newTag: my-tag",
+				},
+			},
+			expected: expected{
+				fileOutput: []string{
+					"images:",
+					"- name: image1",
+					"  newName: foo.bar.foo:8800/foo/image1",
+					"  newTag: v1",
+				}},
+		},
+		{
+			description: "override new name but keep new tag",
+			given: given{
+				args: []string{"image1=my-image1:*"},
+				infileImages: []string{
+					"images:",
+					"- name: image1",
+					"  newName: foo.bar.foo:8800/foo/image1",
+					"  newTag: my-tag",
+				},
+			},
+			expected: expected{
+				fileOutput: []string{
+					"images:",
+					"- name: image1",
+					"  newName: my-image1",
+					"  newTag: my-tag",
+				}},
+		},
+		{
+			description: "keep new name and new tag (rare case)",
+			given: given{
+				args: []string{"image1=*:*"},
+				infileImages: []string{
+					"images:",
+					"- name: image1",
+					"  newName: my-image1",
+					"  newTag: my-tag",
+				},
+			},
+			expected: expected{
+				fileOutput: []string{
+					"images:",
+					"- name: image1",
+					"  newName: my-image1",
+					"  newTag: my-tag",
+				}},
+		},
+		{
+			description: "do not set asterisk as new name for existing image",
+			given: given{
+				args: []string{"image1=*:v1"},
+				infileImages: []string{
+					"images:",
+					"- name: image1",
+					"  newTag: my-tag",
+				},
+			},
+			expected: expected{
+				fileOutput: []string{
+					"images:",
+					"- name: image1",
+					"  newTag: v1",
+				}},
+		},
+		{
+			description: "do not set asterisk as new name",
+			given: given{
+				args: []string{"image1=*:v1"},
+			},
+			expected: expected{
+				fileOutput: []string{
+					"images:",
+					"- name: image1",
+					"  newTag: v1",
+				}},
+		},
+		{
+			description: "do not set asterisk as new tag",
+			given: given{
+				args: []string{"image1=my-image1:*"},
+			},
+			expected: expected{
+				fileOutput: []string{
+					"images:",
+					"- name: image1",
+					"  newName: my-image1",
+				}},
+		},
 	}
 
 	for _, tc := range testCases {