feat: support SourceHydrator applications for image updates

pkg/argocd/argocd.go

@@ -981,6 +981,22 @@ func getApplicationSourceType(app *argocdapi.Application, wbc *WriteBackConfig)
 		return argocdapi.ApplicationSourceTypeDirectory
 	}
 
+	// For SourceHydrator apps, Status.SourceType reflects the sync source (typically
+	// "Directory" since it syncs rendered manifests), not the dry source. If the DrySource
+	// has explicit Helm/Kustomize/Plugin config, use that to determine the actual type.
+	if app.Spec.SourceHydrator != nil {
+		ds := app.Spec.SourceHydrator.DrySource
+		if ds.Helm != nil {
+			return argocdapi.ApplicationSourceTypeHelm
+		}
+		if ds.Kustomize != nil {
+			return argocdapi.ApplicationSourceTypeKustomize
+		}
+		if ds.Plugin != nil {
+			return argocdapi.ApplicationSourceTypePlugin
+		}
+	}
+
 	return app.Status.SourceType
 }
 
@@ -1015,6 +1031,24 @@ func getApplicationSource(ctx context.Context, app *argocdapi.Application, wbc *
 		return &app.Spec.Sources[0]
 	}
 
+	// If the application uses a SourceHydrator, derive the source from its DrySource.
+	// The dry source is the write-back target: it holds the original (unhydrated) manifests.
+	// We construct the ApplicationSource manually (rather than using GetDrySource()) to
+	// include the Helm/Kustomize/Directory/Plugin fields, which downstream code relies on.
+	if app.Spec.SourceHydrator != nil {
+		ds := app.Spec.SourceHydrator.DrySource
+		source := argocdapi.ApplicationSource{
+			RepoURL:        ds.RepoURL,
+			Path:           ds.Path,
+			TargetRevision: ds.TargetRevision,
+			Helm:           ds.Helm,
+			Kustomize:      ds.Kustomize,
+			Directory:      ds.Directory,
+			Plugin:         ds.Plugin,
+		}
+		return &source
+	}
+
 	return app.Spec.Source
 }
 

pkg/argocd/argocd_test.go

@@ -540,6 +540,164 @@ func Test_GetApplicationSource(t *testing.T) {
 
 }
 
+func Test_GetApplicationSource_SourceHydrator(t *testing.T) {
+	t.Run("Get source with Helm config from DrySource", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{
+						RepoURL:        "https://example.com/repo.git",
+						Path:           "charts/myapp",
+						TargetRevision: "main",
+						Helm: &v1alpha1.ApplicationSourceHelm{
+							Parameters: []v1alpha1.HelmParameter{{Name: "image.tag", Value: "1.0.0"}},
+						},
+					},
+				},
+			},
+		}
+
+		appSource := GetApplicationSource(context.Background(), application, nil)
+		require.NotNil(t, appSource)
+		assert.Equal(t, "https://example.com/repo.git", appSource.RepoURL)
+		assert.Equal(t, "charts/myapp", appSource.Path)
+		assert.Equal(t, "main", appSource.TargetRevision)
+		require.NotNil(t, appSource.Helm)
+		assert.Equal(t, "1.0.0", appSource.Helm.Parameters[0].Value)
+	})
+
+	t.Run("Get source with Kustomize config from DrySource", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{
+						RepoURL:   "https://example.com/repo.git",
+						Path:      "overlays/hub",
+						Kustomize: &v1alpha1.ApplicationSourceKustomize{},
+					},
+				},
+			},
+		}
+
+		appSource := GetApplicationSource(context.Background(), application, nil)
+		require.NotNil(t, appSource)
+		assert.NotNil(t, appSource.Kustomize)
+	})
+
+	t.Run("Get source from DrySource without explicit type config", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{
+						RepoURL:        "https://example.com/repo.git",
+						Path:           "overlays/hub",
+						TargetRevision: "main",
+					},
+				},
+			},
+		}
+
+		appSource := GetApplicationSource(context.Background(), application, nil)
+		require.NotNil(t, appSource)
+		assert.Equal(t, "main", appSource.TargetRevision)
+		assert.Nil(t, appSource.Helm)
+		assert.Nil(t, appSource.Kustomize)
+	})
+
+	t.Run("SourceHydrator takes precedence over nil Source", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				Source: nil,
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{
+						RepoURL:        "https://example.com/repo.git",
+						TargetRevision: "develop",
+					},
+				},
+			},
+		}
+
+		appSource := GetApplicationSource(context.Background(), application, nil)
+		require.NotNil(t, appSource)
+		assert.Equal(t, "develop", appSource.TargetRevision)
+	})
+}
+
+func Test_GetApplicationSourceType_SourceHydrator(t *testing.T) {
+	t.Run("Detect Helm from DrySource", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{Helm: &v1alpha1.ApplicationSourceHelm{}},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{SourceType: v1alpha1.ApplicationSourceTypeDirectory},
+		}
+		assert.Equal(t, v1alpha1.ApplicationSourceTypeHelm, GetApplicationSourceType(application, nil))
+	})
+
+	t.Run("Detect Kustomize from DrySource", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{Kustomize: &v1alpha1.ApplicationSourceKustomize{}},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{SourceType: v1alpha1.ApplicationSourceTypeDirectory},
+		}
+		assert.Equal(t, v1alpha1.ApplicationSourceTypeKustomize, GetApplicationSourceType(application, nil))
+	})
+
+	t.Run("Detect Plugin from DrySource", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{Plugin: &v1alpha1.ApplicationSourcePlugin{}},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{SourceType: v1alpha1.ApplicationSourceTypeDirectory},
+		}
+		assert.Equal(t, v1alpha1.ApplicationSourceTypePlugin, GetApplicationSourceType(application, nil))
+	})
+
+	t.Run("Fall back to Status.SourceType when DrySource has no explicit type", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{SourceType: v1alpha1.ApplicationSourceTypeDirectory},
+		}
+		assert.Equal(t, v1alpha1.ApplicationSourceTypeDirectory, GetApplicationSourceType(application, nil))
+	})
+
+	t.Run("DrySource Helm overrides misleading Status.SourceType Directory", func(t *testing.T) {
+		application := &v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "test-app", Namespace: "testns"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{
+						Helm: &v1alpha1.ApplicationSourceHelm{
+							Parameters: []v1alpha1.HelmParameter{{Name: "image.tag", Value: "1.0.0"}},
+						},
+					},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{SourceType: v1alpha1.ApplicationSourceTypeDirectory},
+		}
+		assert.Equal(t, v1alpha1.ApplicationSourceTypeHelm, GetApplicationSourceType(application, nil))
+	})
+}
+
 // Test_MultiSourceHelmAndKustomize_SourceTypeDetection demonstrates the bug fixed by the
 // write-back target check in getApplicationSourceType.
 // The bug scenario:

pkg/argocd/update.go

@@ -375,8 +375,11 @@ func marshalParamsOverride(ctx context.Context, applicationImages *ApplicationIm
 		mergeKustomizeOverride(&params, &newParams)
 		override, err = marshalWithIndent(params, defaultIndent)
 	case ApplicationTypeHelm:
-		if appSource.Helm == nil {
-			return []byte{}, nil
+		// Extract Helm parameters safely; Helm may be nil for SourceHydrator apps
+		// where the source type is auto-detected from files rather than set in the spec.
+		var helmParams []v1alpha1.HelmParameter
+		if appSource.Helm != nil {
+			helmParams = appSource.Helm.Parameters
 		}
 
 		if wbc != nil && !strings.HasPrefix(filepath.Base(wbc.Target), common.DefaultTargetFilePrefix) {
@@ -425,7 +428,7 @@ func marshalParamsOverride(ctx context.Context, applicationImages *ApplicationIm
 					}
 				} else {
 					// image-tag is present, so continue to process image-tag
-					helmParamVer := getHelmParam(appSource.Helm.Parameters, helmParamVersion)
+					helmParamVer := getHelmParam(helmParams, helmParamVersion)
 					var tagValue string
 					if helmParamVer == nil {
 						// Parameter not pre-defined in the Application - use the image's tag data as fallback
@@ -440,7 +443,7 @@ func marshalParamsOverride(ctx context.Context, applicationImages *ApplicationIm
 					}
 				}
 
-				helmParamN := getHelmParam(appSource.Helm.Parameters, helmParamName)
+				helmParamN := getHelmParam(helmParams, helmParamName)
 				// Determine which value to use for the image name parameter
 				var valueToSet string
 				if helmParamN == nil {
@@ -475,6 +478,9 @@ func marshalParamsOverride(ctx context.Context, applicationImages *ApplicationIm
 
 			override, err = marshalWithIndent(&helmNewValues, defaultIndent)
 		} else {
+			if appSource.Helm == nil {
+				return []byte{}, nil
+			}
 			var params helmOverride
 			newParams := helmOverride{
 				Helm: helmParameters{

pkg/argocd/update_test.go

@@ -3402,6 +3402,89 @@ kustomize:
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(yamlOutput)),
 			"Output should be valid Kustomize override YAML with updated image")
 	})
+
+	t.Run("SourceHydrator app with nil Helm writes custom values file via fallback", func(t *testing.T) {
+		expected := `
+# auto generated by argocd image updater
+
+image:
+  tag: v0.0.0
+  name: nginx
+`
+		app := v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "hydrator-app"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{
+				SourceType: v1alpha1.ApplicationSourceTypeDirectory,
+				Summary:    v1alpha1.ApplicationSummary{Images: []string{"nginx:v0.0.0"}},
+			},
+		}
+		im := NewImage(image.NewFromIdentifier("nginx"))
+		im.HelmImageName = "image.name"
+		im.HelmImageTag = "image.tag"
+		applicationImages := &ApplicationImages{
+			Application: app,
+			Images:      ImageList{im},
+			WriteBackConfig: &WriteBackConfig{
+				Method: WriteBackGit,
+				Target: "./values.yaml",
+			},
+		}
+
+		yamlOutput, err := marshalParamsOverride(context.Background(), applicationImages, nil)
+		require.NoError(t, err)
+		assert.NotEmpty(t, yamlOutput)
+		assert.Equal(t, strings.TrimSpace(strings.ReplaceAll(expected, "\t", "  ")), strings.TrimSpace(string(yamlOutput)))
+	})
+
+	t.Run("SourceHydrator app with Helm in DrySource writes default override file", func(t *testing.T) {
+		expected := `
+helm:
+  parameters:
+  - name: image.name
+    value: nginx
+    forcestring: true
+  - name: image.tag
+    value: v1.0.0
+    forcestring: true
+`
+		app := v1alpha1.Application{
+			ObjectMeta: v1.ObjectMeta{Name: "hydrator-app"},
+			Spec: v1alpha1.ApplicationSpec{
+				SourceHydrator: &v1alpha1.SourceHydrator{
+					DrySource: v1alpha1.DrySource{
+						Helm: &v1alpha1.ApplicationSourceHelm{
+							Parameters: []v1alpha1.HelmParameter{
+								{Name: "image.name", Value: "nginx", ForceString: true},
+								{Name: "image.tag", Value: "v1.0.0", ForceString: true},
+							},
+						},
+					},
+				},
+			},
+			Status: v1alpha1.ApplicationStatus{SourceType: v1alpha1.ApplicationSourceTypeDirectory},
+		}
+		im := NewImage(image.NewFromIdentifier("nginx"))
+		im.HelmImageName = "image.name"
+		im.HelmImageTag = "image.tag"
+		applicationImages := &ApplicationImages{
+			Application: app,
+			Images:      ImageList{im},
+			WriteBackConfig: &WriteBackConfig{
+				Method: WriteBackGit,
+				Target: ".argocd-source-hydrator-app.yaml",
+			},
+		}
+
+		yamlOutput, err := marshalParamsOverride(context.Background(), applicationImages, nil)
+		require.NoError(t, err)
+		assert.NotEmpty(t, yamlOutput)
+		assert.Equal(t, strings.TrimSpace(strings.ReplaceAll(expected, "\t", "  ")), strings.TrimSpace(string(yamlOutput)))
+	})
 }
 
 func Test_GetHelmValue(t *testing.T) {