fix: for kustomize.buildOptions.<version> per-version build options are never applied #27673

reposerver/repository/repository.go

@@ -1713,7 +1713,15 @@ func GenerateManifests(ctx context.Context, appPath, repoRoot, revision string,
 			return nil, fmt.Errorf("could not parse kubernetes version %s: %w", q.ApplicationSource.GetKubeVersionOrDefault(q.KubeVersion), err)
 		}
 		k := kustomize.NewKustomizeApp(repoRoot, appPath, q.Repo.GetGitCreds(gitCredsStore), repoURL, kustomizeBinary, q.Repo.Proxy, q.Repo.NoProxy)
-		targetObjs, _, commands, err = k.Build(q.ApplicationSource.Kustomize, q.KustomizeOptions, env, &kustomize.BuildOpts{
+		kustomizeOpts := q.KustomizeOptions
+		if kustomizeOpts != nil {
+			if effectiveBuildOptions := settings.GetKustomizeBuildOptions(kustomizeOpts, *q.ApplicationSource); effectiveBuildOptions != kustomizeOpts.BuildOptions {
+				optsCopy := *kustomizeOpts
+				optsCopy.BuildOptions = effectiveBuildOptions
+				kustomizeOpts = &optsCopy
+			}
+		}
+		targetObjs, _, commands, err = k.Build(q.ApplicationSource.Kustomize, kustomizeOpts, env, &kustomize.BuildOpts{
 			KubeVersion: kubeVersion,
 			APIVersions: q.ApplicationSource.GetAPIVersionsOrDefault(q.ApiVersions),
 		})
@@ -2582,7 +2590,15 @@ func populateKustomizeAppDetails(res *apiclient.RepoAppDetailsResponse, q *apicl
 		ApplicationSource: q.Source,
 	}
 	env := newEnv(&fakeManifestRequest, reversion)
-	_, images, _, err := k.Build(q.Source.Kustomize, q.KustomizeOptions, env, nil)
+	kustomizeOpts := q.KustomizeOptions
+	if kustomizeOpts != nil {
+		if effectiveBuildOptions := settings.GetKustomizeBuildOptions(kustomizeOpts, *q.Source); effectiveBuildOptions != kustomizeOpts.BuildOptions {
+			optsCopy := *kustomizeOpts
+			optsCopy.BuildOptions = effectiveBuildOptions
+			kustomizeOpts = &optsCopy
+		}
+	}
+	_, images, _, err := k.Build(q.Source.Kustomize, kustomizeOpts, env, nil)
 	if err != nil {
 		return err
 	}

util/settings/settings.go

@@ -282,6 +282,23 @@ func GetKustomizeBinaryPath(ks *v1alpha1.KustomizeOptions, source v1alpha1.Appli
 	return "", nil
 }
 
+// GetKustomizeBuildOptions returns the build options for the kustomize invocation based on the provided KustomizeOptions
+// and ApplicationSource. If the source requests a specific kustomize version and that version defines per-version build
+// options, those are returned. Otherwise, the global build options are returned.
+func GetKustomizeBuildOptions(ks *v1alpha1.KustomizeOptions, source v1alpha1.ApplicationSource) string {
+	if ks == nil {
+		return ""
+	}
+	if source.Kustomize != nil && source.Kustomize.Version != "" {
+		for _, ver := range ks.Versions {
+			if ver.Name == source.Kustomize.Version && ver.BuildOptions != "" {
+				return ver.BuildOptions
+			}
+		}
+	}
+	return ks.BuildOptions
+}
+
 // Credentials for accessing a Git repository
 type Repository struct {
 	// The URL to the repository

util/settings/settings_test.go

@@ -871,6 +871,50 @@ func Test_GetKustomizeBinaryPath(t *testing.T) {
 	})
 }
 
+func Test_GetKustomizeBuildOptions(t *testing.T) {
+	ko := &v1alpha1.KustomizeOptions{
+		BuildOptions: "--opt1 val1",
+		Versions: []v1alpha1.KustomizeVersion{
+			{Name: "v1", Path: "path_v1"},
+			{Name: "v2", Path: "path_v2", BuildOptions: "--opt2 val2"},
+			{Name: "v3", Path: "path_v3", BuildOptions: "--opt3 val3"},
+		},
+	}
+
+	t.Run("NilOptions", func(t *testing.T) {
+		result := GetKustomizeBuildOptions(nil, v1alpha1.ApplicationSource{})
+		assert.Empty(t, result)
+	})
+
+	t.Run("NoVersionRequested", func(t *testing.T) {
+		result := GetKustomizeBuildOptions(ko, v1alpha1.ApplicationSource{})
+		assert.Equal(t, "--opt1 val1", result)
+	})
+
+	t.Run("VersionWithBuildOptions", func(t *testing.T) {
+		result := GetKustomizeBuildOptions(ko, v1alpha1.ApplicationSource{
+			Kustomize: &v1alpha1.ApplicationSourceKustomize{Version: "v2"},
+		})
+		assert.Equal(t, "--opt2 val2", result)
+	})
+
+	t.Run("VersionWithoutBuildOptions", func(t *testing.T) {
+		// v1 has no BuildOptions — should fall back to global
+		result := GetKustomizeBuildOptions(ko, v1alpha1.ApplicationSource{
+			Kustomize: &v1alpha1.ApplicationSourceKustomize{Version: "v1"},
+		})
+		assert.Equal(t, "--opt1 val1", result)
+	})
+
+	t.Run("UnknownVersion", func(t *testing.T) {
+		// unregistered version — falls back to global
+		result := GetKustomizeBuildOptions(ko, v1alpha1.ApplicationSource{
+			Kustomize: &v1alpha1.ApplicationSourceKustomize{Version: "v99"},
+		})
+		assert.Equal(t, "--opt1 val1", result)
+	})
+}
+
 func TestGetGoogleAnalytics(t *testing.T) {
 	_, settingsManager := fixtures(t.Context(), map[string]string{
 		"ga.trackingid": "123",