Merge pull request #29190 from backstage/rugvip/norm

core-compat-api: better normalization of discovered route paths

.changeset/odd-boxes-pump.md

@@ -0,0 +1,5 @@
+---
+'@backstage/core-compat-api': patch
+---
+
+Improved route path normalization when converting existing route elements in `converLegacyApp`, for example handling trailing `/*` in paths.

packages/core-compat-api/src/collectEntityPageContents.ts

@@ -25,6 +25,7 @@ import {
   EntityCardBlueprint,
   EntityContentBlueprint,
 } from '@backstage/plugin-catalog-react/alpha';
+import { normalizeRoutePath } from './normalizeRoutePath';
 
 const ENTITY_SWITCH_KEY = 'core.backstage.entitySwitch';
 const ENTITY_ROUTE_KEY = 'plugin.catalog.entityLayoutRoute';
@@ -114,7 +115,7 @@ export function collectEntityPageContents(
               name,
               factory(originalFactory, { apis }) {
                 return originalFactory({
-                  defaultPath: pageNode.path,
+                  defaultPath: normalizeRoutePath(pageNode.path),
                   defaultTitle: pageNode.title,
                   filter: mergedIf && (entity => mergedIf(entity, { apis })),
                   loader: () => Promise.resolve(pageNode.children),

packages/core-compat-api/src/collectLegacyRoutes.tsx

@@ -41,6 +41,7 @@ import {
 } from './convertLegacyRouteRef';
 import { compatWrapper } from './compatWrapper';
 import { collectEntityPageContents } from './collectEntityPageContents';
+import { normalizeRoutePath } from './normalizeRoutePath';
 
 /*
 
@@ -236,7 +237,7 @@ export function collectLegacyRoutes(
           factory(originalFactory, { inputs: _inputs }) {
             // todo(blam): why do we not use the inputs here?
             return originalFactory({
-              defaultPath: path[0] === '/' ? path.slice(1) : path,
+              defaultPath: normalizeRoutePath(path),
               routeRef: routeRef ? convertLegacyRouteRef(routeRef) : undefined,
               loader: async () =>
                 compatWrapper(

packages/core-compat-api/src/normalizeRoutePath.test.ts

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { normalizeRoutePath } from './normalizeRoutePath';
+
+describe('normalizeRoutePath', () => {
+  it('should normalize the path', () => {
+    expect(normalizeRoutePath('')).toBe('/');
+    expect(normalizeRoutePath('/')).toBe('/');
+    expect(normalizeRoutePath('/*')).toBe('/');
+    expect(normalizeRoutePath('/////')).toBe('/');
+    expect(normalizeRoutePath('*//*//*')).toBe('/');
+    expect(normalizeRoutePath('/foo')).toBe('/foo');
+    expect(normalizeRoutePath('/foo/')).toBe('/foo');
+    expect(normalizeRoutePath('/foo/*')).toBe('/foo');
+    expect(normalizeRoutePath('/foo/**')).toBe('/foo');
+    expect(normalizeRoutePath('/foo//**')).toBe('/foo');
+    expect(normalizeRoutePath('/foo/*/*')).toBe('/foo');
+    expect(normalizeRoutePath('//foo/*/*')).toBe('/foo');
+    expect(normalizeRoutePath('/foo/bar//*/*')).toBe('/foo/bar');
+    expect(normalizeRoutePath('/foo//bar//*/*')).toBe('/foo//bar');
+  });
+});

packages/core-compat-api/src/normalizeRoutePath.ts

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Normalizes the path to make sure it always starts with a single '/' and do not end with '/' or '*' unless empty
+ */
+export function normalizeRoutePath(path: string) {
+  let normalized = path;
+  while (normalized.endsWith('/') || normalized.endsWith('*')) {
+    normalized = normalized.slice(0, -1);
+  }
+  while (normalized.startsWith('/')) {
+    normalized = normalized.slice(1);
+  }
+  if (!normalized) {
+    return '/';
+  }
+  return `/${normalized}`;
+}