From e2eeb1dde10b99cc53696ab69157be205379f01a Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Mon, 12 Aug 2024 14:21:23 +0200
Subject: [PATCH 1/5] chore: wip some things

Signed-off-by: blam <ben@blam.sh>
---
 .../src/blueprints/PageBlueprint.tsx          | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx b/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx
index b224ea491e..89ac938505 100644
--- a/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx
+++ b/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx
@@ -64,3 +64,68 @@ export const PageBlueprint = createExtensionBlueprint({
     }
   },
 });
+
+const homePage = PageBlueprint.make({
+  params: {
+    defaultPath: '/home',
+    loader: async () => <h1>Home</h1>,
+  },
+});
+
+const homePlugin = createPlugin({
+  id: 'asd',
+  extensions: [homePage],
+});
+
+// overrides-package locally
+
+/* 
+
+# TODO
+- [ ] Decorate getExtension(...) extension definitions with a namespace
+- [ ] Implement plugin.override([...])
+
+*/
+
+// import plugin from '@backstage/plugin-home';
+
+// export const exp1 = plugin.override([
+//   plugin.getExtension('page:home').override({
+//     *factory(originalFactory) {
+//       yield* originalFactory();
+//       yield coreExtensionData.routePath('/backstage');
+//       // return [...originalFactory(), coreExtensionData.routePath('/backstage')];
+//       // return originalFactory({
+//       //   defaultPath: '/backstage',
+//       // });
+//     },
+//   }),
+//   PageBlueprint.make({
+//     name: 'home',
+//     params: {
+//       defaultPath: '/home',
+//       loader: async () => <h1>Home</h1>,
+//     },
+//   })
+// ]);
+
+// // kind:namespace/name
+// // entity-card:github/issues
+// // entity-card:github/pull-requests
+// // page:catalog
+
+// export const exp2 = createExtensionOverrides({
+//   extensions: [
+//     homePlugin.getExtension('page:home').override({
+//       // namespace: 'home',
+//       *factory(originalFactory) {
+//         yield* originalFactory();
+//         yield coreExtensionData.routePath('/backstage');
+//         // return [...originalFactory(), coreExtensionData.routePath('/backstage')];
+//         // return originalFactory({
+//         //   defaultPath: '/backstage',
+//         // });
+//       },
+//     })
+//   ]
+// })

From d0ab4d33566a6fc27a83d7c71d1a1cb083450728 Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Mon, 12 Aug 2024 17:15:30 +0200
Subject: [PATCH 2/5] feat: implementing plugin overrides
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Patrik Oldsberg <poldsberg@gmail.com>
Co-authored-by: Fredrik Adelöw <freben@users.noreply.github.com>
Co-authored-by: Camila Belo <camilaibs@users.noreply.github.com>
Co-authored-by: Johan Haals <johan@haals.se>
Signed-off-by: blam <ben@blam.sh>
---
 .../src/blueprints/PageBlueprint.tsx          | 65 -------------------
 .../src/wiring/createPlugin.test.ts           | 61 ++++++++++++++++-
 .../src/wiring/createPlugin.ts                | 19 +++++-
 .../frontend-plugin-api/src/wiring/types.ts   |  3 +
 4 files changed, 81 insertions(+), 67 deletions(-)

diff --git a/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx b/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx
index 89ac938505..b224ea491e 100644
--- a/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx
+++ b/packages/frontend-plugin-api/src/blueprints/PageBlueprint.tsx
@@ -64,68 +64,3 @@ export const PageBlueprint = createExtensionBlueprint({
     }
   },
 });
-
-const homePage = PageBlueprint.make({
-  params: {
-    defaultPath: '/home',
-    loader: async () => <h1>Home</h1>,
-  },
-});
-
-const homePlugin = createPlugin({
-  id: 'asd',
-  extensions: [homePage],
-});
-
-// overrides-package locally
-
-/* 
-
-# TODO
-- [ ] Decorate getExtension(...) extension definitions with a namespace
-- [ ] Implement plugin.override([...])
-
-*/
-
-// import plugin from '@backstage/plugin-home';
-
-// export const exp1 = plugin.override([
-//   plugin.getExtension('page:home').override({
-//     *factory(originalFactory) {
-//       yield* originalFactory();
-//       yield coreExtensionData.routePath('/backstage');
-//       // return [...originalFactory(), coreExtensionData.routePath('/backstage')];
-//       // return originalFactory({
-//       //   defaultPath: '/backstage',
-//       // });
-//     },
-//   }),
-//   PageBlueprint.make({
-//     name: 'home',
-//     params: {
-//       defaultPath: '/home',
-//       loader: async () => <h1>Home</h1>,
-//     },
-//   })
-// ]);
-
-// // kind:namespace/name
-// // entity-card:github/issues
-// // entity-card:github/pull-requests
-// // page:catalog
-
-// export const exp2 = createExtensionOverrides({
-//   extensions: [
-//     homePlugin.getExtension('page:home').override({
-//       // namespace: 'home',
-//       *factory(originalFactory) {
-//         yield* originalFactory();
-//         yield coreExtensionData.routePath('/backstage');
-//         // return [...originalFactory(), coreExtensionData.routePath('/backstage')];
-//         // return originalFactory({
-//         //   defaultPath: '/backstage',
-//         // });
-//       },
-//     })
-//   ]
-// })
diff --git a/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts b/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts
index 76cc030be3..f1a0817c80 100644
--- a/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts
+++ b/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts
@@ -148,7 +148,28 @@ describe('createPlugin', () => {
     });
     expect(plugin).toBeDefined();
 
-    expect(plugin.getExtension('test/1')).toBe(Extension1);
+    expect(plugin.getExtension('test/1')).toMatchInlineSnapshot(`
+      {
+        "$$type": "@backstage/ExtensionDefinition",
+        "attachTo": {
+          "id": "test/output",
+          "input": "names",
+        },
+        "configSchema": undefined,
+        "disabled": false,
+        "factory": [Function],
+        "inputs": {},
+        "kind": undefined,
+        "name": "1",
+        "namespace": "test",
+        "output": [
+          [Function],
+        ],
+        "override": [Function],
+        "toString": [Function],
+        "version": "v2",
+      }
+    `);
     // @ts-expect-error
     expect(plugin.getExtension('nonexistent')).toBeUndefined();
 
@@ -250,4 +271,42 @@ describe('createPlugin', () => {
       }),
     ).toThrow("Plugin 'test' provided duplicate extensions: test/2, test/3");
   });
+
+  describe('overrides', () => {
+    it('should allow overriding extensions that have a matching ID, while keeping old extensions that do not have overlapping IDs', async () => {
+      const plugin = createPlugin({
+        id: 'test',
+        extensions: [Extension1, Extension2, outputExtension],
+      });
+
+      expect(plugin.getExtension('test/1')).toMatchObject({
+        namespace: 'test',
+      });
+
+      await renderWithEffects(
+        createTestAppRoot({
+          features: [
+            plugin.withOverrides({
+              extensions: [
+                plugin.getExtension('test/1').override({
+                  factory() {
+                    return [nameExtensionDataRef('overridden')];
+                  },
+                }),
+              ],
+            }),
+          ],
+          config: {
+            app: {
+              extensions: [{ 'app/root': false }],
+            },
+          },
+        }),
+      );
+
+      await expect(
+        screen.findByText('Names: extension-2, overridden'),
+      ).resolves.toBeInTheDocument();
+    });
+  });
 });
diff --git a/packages/frontend-plugin-api/src/wiring/createPlugin.ts b/packages/frontend-plugin-api/src/wiring/createPlugin.ts
index 1d2a12ffe2..2f7a813c90 100644
--- a/packages/frontend-plugin-api/src/wiring/createPlugin.ts
+++ b/packages/frontend-plugin-api/src/wiring/createPlugin.ts
@@ -78,7 +78,7 @@ export function createPlugin<
   for (const def of options.extensions ?? []) {
     const ext = resolveExtensionDefinition(def, { namespace: options.id });
     extensions.push(ext);
-    extensionDefinitionsById.set(ext.id, def);
+    extensionDefinitionsById.set(ext.id, { ...def, namespace: options.id });
   }
 
   if (extensions.length !== extensionDefinitionsById.size) {
@@ -110,6 +110,23 @@ export function createPlugin<
     toString() {
       return `Plugin{id=${options.id}}`;
     },
+    withOverrides(overrides) {
+      const overrideExtensionIds = new Set(
+        overrides.extensions.map(
+          e => resolveExtensionDefinition(e, { namespace: options.id }).id,
+        ),
+      );
+      const nonOverridenExtensions = (options.extensions ?? []).filter(
+        e =>
+          !overrideExtensionIds.has(
+            resolveExtensionDefinition(e, { namespace: options.id }).id,
+          ),
+      );
+      return createPlugin({
+        ...options,
+        extensions: [...nonOverridenExtensions, ...overrides.extensions],
+      });
+    },
   } as InternalBackstagePlugin<TRoutes, TExternalRoutes>;
 }
 
diff --git a/packages/frontend-plugin-api/src/wiring/types.ts b/packages/frontend-plugin-api/src/wiring/types.ts
index b1afd4e7ea..4a7d972b37 100644
--- a/packages/frontend-plugin-api/src/wiring/types.ts
+++ b/packages/frontend-plugin-api/src/wiring/types.ts
@@ -51,6 +51,9 @@ export interface BackstagePlugin<
   readonly routes: TRoutes;
   readonly externalRoutes: TExternalRoutes;
   getExtension<TId extends keyof TExtensionMap>(id: TId): TExtensionMap[TId];
+  withOverrides(options: {
+    extensions: Array<ExtensionDefinition<any, any>>;
+  }): BackstagePlugin<TRoutes, TExternalRoutes, TExtensionMap>;
 }
 
 /** @public */

From b0ef2dc0ba5b604bdbf7a87f4026b9975cfd05ba Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Tue, 13 Aug 2024 09:12:21 +0200
Subject: [PATCH 3/5] chore: restructure tests and fix api-report

Signed-off-by: blam <ben@blam.sh>
---
 packages/frontend-plugin-api/api-report.md    |  4 +++
 .../src/wiring/createPlugin.test.ts           | 34 ++++++++++++++++---
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/packages/frontend-plugin-api/api-report.md b/packages/frontend-plugin-api/api-report.md
index 6d548e3c26..f841fc2ce2 100644
--- a/packages/frontend-plugin-api/api-report.md
+++ b/packages/frontend-plugin-api/api-report.md
@@ -356,6 +356,10 @@ export interface BackstagePlugin<
   readonly id: string;
   // (undocumented)
   readonly routes: TRoutes;
+  // (undocumented)
+  withOverrides(options: {
+    extensions: Array<ExtensionDefinition<any, any>>;
+  }): BackstagePlugin<TRoutes, TExternalRoutes, TExtensionMap>;
 }
 
 export { BackstageUserIdentity };
diff --git a/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts b/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts
index f1a0817c80..f76e4ec9a5 100644
--- a/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts
+++ b/packages/frontend-plugin-api/src/wiring/createPlugin.test.ts
@@ -273,16 +273,42 @@ describe('createPlugin', () => {
   });
 
   describe('overrides', () => {
+    it('should return a plugin instance with the correct namespace', () => {
+      const plugin = createPlugin({
+        id: 'test',
+        extensions: [Extension1, Extension2],
+      });
+
+      expect(plugin.getExtension('test/1')).toMatchInlineSnapshot(`
+        {
+          "$$type": "@backstage/ExtensionDefinition",
+          "attachTo": {
+            "id": "test/output",
+            "input": "names",
+          },
+          "configSchema": undefined,
+          "disabled": false,
+          "factory": [Function],
+          "inputs": {},
+          "kind": undefined,
+          "name": "1",
+          "namespace": "test",
+          "output": [
+            [Function],
+          ],
+          "override": [Function],
+          "toString": [Function],
+          "version": "v2",
+        }
+      `);
+    });
+
     it('should allow overriding extensions that have a matching ID, while keeping old extensions that do not have overlapping IDs', async () => {
       const plugin = createPlugin({
         id: 'test',
         extensions: [Extension1, Extension2, outputExtension],
       });
 
-      expect(plugin.getExtension('test/1')).toMatchObject({
-        namespace: 'test',
-      });
-
       await renderWithEffects(
         createTestAppRoot({
           features: [

From 99abb6bf299366bd311ec6afdf9bba6c1e2be309 Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Tue, 13 Aug 2024 09:16:07 +0200
Subject: [PATCH 4/5] chore: added a simple changeset

Signed-off-by: blam <ben@blam.sh>
---
 .changeset/fresh-timers-walk.md | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 .changeset/fresh-timers-walk.md

diff --git a/.changeset/fresh-timers-walk.md b/.changeset/fresh-timers-walk.md
new file mode 100644
index 0000000000..647e72830a
--- /dev/null
+++ b/.changeset/fresh-timers-walk.md
@@ -0,0 +1,20 @@
+---
+'@backstage/frontend-plugin-api': patch
+---
+
+Support overriding of plugin extensions using the new `plugin.override` method.
+
+```tsx
+import homePlugin from '@backstage/plugin-home';
+
+export default homePlugin.override({
+  extensions: [
+    homePage.getExtension('page:home').override({
+      *factory(originalFactory) {
+        yield* originalFactory();
+        yield coreExtensionData.reactElement(<h1>My custom home page</h1>);
+      },
+    }),
+  ],
+});
+```

From aa11af2499cdf3de2f891d0020e9bddfb547ad58 Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Tue, 13 Aug 2024 09:19:15 +0200
Subject: [PATCH 5/5] chore: updating changeset

Signed-off-by: blam <ben@blam.sh>
---
 .changeset/fresh-timers-walk.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.changeset/fresh-timers-walk.md b/.changeset/fresh-timers-walk.md
index 647e72830a..a187bede83 100644
--- a/.changeset/fresh-timers-walk.md
+++ b/.changeset/fresh-timers-walk.md
@@ -2,12 +2,12 @@
 '@backstage/frontend-plugin-api': patch
 ---
 
-Support overriding of plugin extensions using the new `plugin.override` method.
+Support overriding of plugin extensions using the new `plugin.withOverrides` method.
 
 ```tsx
 import homePlugin from '@backstage/plugin-home';
 
-export default homePlugin.override({
+export default homePlugin.withOverrides({
   extensions: [
     homePage.getExtension('page:home').override({
       *factory(originalFactory) {