fix: Kustomize skip commit if nothing changed (argoproj-labs#607)

Signed-off-by: Fs02 <[email protected]>
Signed-off-by: Tchoupinax <[email protected]>

pkg/argocd/git.go

@@ -329,40 +329,51 @@ func writeKustomization(app *v1alpha1.Application, wbc *WriteBackConfig, gitC gi
 		return err, false
 	}
 
-	if err = updateKustomizeFile(filterFunc, kustFile); err != nil {
-		return err, false
-	}
-
-	return nil, false
+	return updateKustomizeFile(filterFunc, kustFile)
 }
 
 // updateKustomizeFile reads the kustomization file at path, applies the filter to it, and writes the result back
 // to the file. This is the same behavior as kyaml.UpdateFile, but it preserves the original order
 // of YAML fields to minimize git diffs.
-func updateKustomizeFile(filter kyaml.Filter, path string) error {
+func updateKustomizeFile(filter kyaml.Filter, path string) (error, bool) {
 	// Read the yaml
 	y, err := kyaml.ReadFile(path)
 	if err != nil {
-		return err
+		return err, false
+	}
+
+	originalData, err := y.String()
+	if err != nil {
+		return err, false
 	}
 
 	// Update the yaml
 	yCpy := y.Copy()
 	if err := yCpy.PipeE(filter); err != nil {
-		return err
+		return err, false
 	}
 
 	// Preserve the original order of fields
 	if err := order.SyncOrder(y, yCpy); err != nil {
-		return err
+		return err, false
+	}
+
+	override, err := yCpy.String()
+	if err != nil {
+		return err, false
+	}
+
+	if originalData == override {
+		log.Debugf("target parameter file and marshaled data are the same, skipping commit.")
+		return nil, true
 	}
 
 	// Write the yaml
-	if err := kyaml.WriteFile(yCpy, path); err != nil {
-		return err
+	if err := os.WriteFile(path, []byte(override), 0600); err != nil {
+		return err, false
 	}
 
-	return nil
+	return nil, false
 }
 
 func imagesFilter(images v1alpha1.KustomizeImages) (kyaml.Filter, error) {

pkg/argocd/git_test.go

@@ -270,19 +270,49 @@ func Test_updateKustomizeFile(t *testing.T) {
 `,
 			filter: filter,
 		},
+		{
+			name: "no-change",
+			content: `images:
+- name: foo
+  digest: sha23456
+`,
+			wantContent: "",
+			filter:      filter,
+		},
+		{
+			name: "invalid-path",
+			content: `images:
+- name: foo
+  digest: sha12345
+`,
+			wantContent: "",
+			filter:      filter,
+			wantErr:     true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			path := makeTmpKustomization(t, []byte(tt.content))
-			err := updateKustomizeFile(tt.filter, path)
+			var path string
+			if tt.wantErr {
+				path = "/invalid-path"
+			} else {
+				path = makeTmpKustomization(t, []byte(tt.content))
+			}
+
+			err, skip := updateKustomizeFile(tt.filter, path)
 			if tt.wantErr {
 				assert.Error(t, err)
+				assert.False(t, skip)
+			} else if tt.name == "no-change" {
+				assert.Nil(t, err)
+				assert.True(t, skip)
 			} else {
 				got, err := os.ReadFile(path)
 				if err != nil {
 					t.Fatal(err)
 				}
 				assert.Equal(t, tt.wantContent, string(got))
+				assert.False(t, skip)
 			}
 		})
 	}