fix: correct lookup for the kustomization file when applying patches (cherry-pick #22024) (#22086)

Signed-off-by: nitishfy <justnitish06@gmail.com>
Co-authored-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

Author: nitishfy

util/kustomize/kustomize.go

@@ -25,7 +25,7 @@ import (
 	"github.com/argoproj/argo-cd/v2/util/proxy"
 )
 
-// represents a Docker image in the format NAME[:TAG].
+// Image represents a Docker image in the format NAME[:TAG].
 type Image = string
 
 type BuildOpts struct {
@@ -69,7 +69,29 @@ type kustomize struct {
 	noProxy string
 }
 
-var _ Kustomize = &kustomize{}
+var KustomizationNames = []string{"kustomization.yaml", "kustomization.yml", "Kustomization"}
+
+// IsKustomization checks if the given file name matches any known kustomization file names.
+func IsKustomization(path string) bool {
+	for _, kustomization := range KustomizationNames {
+		if path == kustomization {
+			return true
+		}
+	}
+	return false
+}
+
+// findKustomizeFile looks for any known kustomization file in the path
+func findKustomizeFile(dir string) string {
+	for _, file := range KustomizationNames {
+		path := filepath.Join(dir, file)
+		if _, err := os.Stat(path); err == nil {
+			return file
+		}
+	}
+
+	return ""
+}
 
 func (k *kustomize) getBinaryPath() string {
 	if k.binaryPath != "" {
@@ -252,7 +274,13 @@ func (k *kustomize) Build(opts *v1alpha1.ApplicationSourceKustomize, kustomizeOp
 		}
 
 		if len(opts.Patches) > 0 {
-			kustomizationPath := filepath.Join(k.path, "kustomization.yaml")
+			kustFile := findKustomizeFile(k.path)
+			// If the kustomization file is not found, return early.
+			// There is no point reading the kustomization path if it doesn't exist.
+			if kustFile == "" {
+				return nil, nil, nil, fmt.Errorf("kustomization file not found in the path")
+			}
+			kustomizationPath := filepath.Join(k.path, kustFile)
 			b, err := os.ReadFile(kustomizationPath)
 			if err != nil {
 				return nil, nil, nil, fmt.Errorf("failed to load kustomization.yaml: %w", err)
@@ -369,17 +397,6 @@ func isHelmEnabled(buildOptions string) bool {
 	return strings.Contains(buildOptions, "--enable-helm")
 }
 
-var KustomizationNames = []string{"kustomization.yaml", "kustomization.yml", "Kustomization"}
-
-func IsKustomization(path string) bool {
-	for _, kustomization := range KustomizationNames {
-		if path == kustomization {
-			return true
-		}
-	}
-	return false
-}
-
 // semver/v3 doesn't export the regexp anymore, so shamelessly copied it over to
 // here.
 // https://github.com/Masterminds/semver/blob/49c09bfed6adcffa16482ddc5e5588cffff9883a/version.go#L42

util/kustomize/kustomize_test.go

@@ -18,14 +18,13 @@ import (
 )
 
 const (
-	kustomization1  = "kustomization_yaml"
-	kustomization2a = "kustomization_yml"
-	kustomization2b = "Kustomization"
-	kustomization3  = "force_common"
-	kustomization4  = "custom_version"
-	kustomization5  = "kustomization_yaml_patches"
-	kustomization6  = "kustomization_yaml_components"
-	kustomization7  = "label_without_selector"
+	kustomization1 = "kustomization_yaml"
+	kustomization3 = "force_common"
+	kustomization4 = "custom_version"
+	kustomization5 = "kustomization_yaml_patches"
+	kustomization6 = "kustomization_yaml_components"
+	kustomization7 = "label_without_selector"
+	kustomization8 = "kustomization_yaml_patches_empty"
 )
 
 func testDataDir(tb testing.TB, testData string) (string, error) {
@@ -65,7 +64,7 @@ func TestKustomizeBuild(t *testing.T) {
 		Replicas: []v1alpha1.KustomizeReplica{
 			{
 				Name:  "nginx-deployment",
-				Count: intstr.FromInt(2),
+				Count: intstr.FromInt32(2),
 			},
 			{
 				Name:  "web",
@@ -512,3 +511,28 @@ func TestKustomizeBuildPatches(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, "test", name)
 }
+
+func TestFailKustomizeBuildPatches(t *testing.T) {
+	appPath, err := testDataDir(t, kustomization8)
+	require.NoError(t, err)
+	kustomize := NewKustomizeApp(appPath, appPath, git.NopCreds{}, "", "", "", "")
+
+	kustomizeSource := v1alpha1.ApplicationSourceKustomize{
+		Patches: []v1alpha1.KustomizePatch{
+			{
+				Patch: `[ { "op": "replace", "path": "/spec/template/spec/containers/0/ports/0/containerPort", "value": 443 },  { "op": "replace", "path": "/spec/template/spec/containers/0/name", "value": "test" }]`,
+				Target: &v1alpha1.KustomizeSelector{
+					KustomizeResId: v1alpha1.KustomizeResId{
+						KustomizeGvk: v1alpha1.KustomizeGvk{
+							Kind: "Deployment",
+						},
+						Name: "nginx-deployment",
+					},
+				},
+			},
+		},
+	}
+
+	_, _, _, err = kustomize.Build(&kustomizeSource, nil, nil, nil)
+	require.EqualError(t, err, "kustomization file not found in the path")
+}

util/kustomize/testdata/kustomization_yaml_patches_empty/Kustomization.yaml

@@ -0,0 +1,3 @@
+# This is an invalid kustomization file
+resources:
+  - ./deployment.yaml

util/kustomize/testdata/kustomization_yaml_patches_empty/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+  labels:
+    app: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+        - name: nginx
+          image: nginx:1.15.4
+          ports:
+            - containerPort: 80