frontend-plugin-api: support feature-level predicates

This lets plugin and module instances apply a shared condition to all of their extensions, while preserving extension-level conditions by combining them with logical AND during app spec resolution.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts

@@ -532,4 +532,88 @@ describe('resolveAppNodeSpecs', () => {
     expect(specs).toHaveLength(1);
     expect(specs[0].if).toEqual(ifPredicate);
   });
+
+  it('should apply plugin if predicates to all plugin extensions', () => {
+    const dataRef = createExtensionDataRef<string>().with({ id: 'test.data' });
+    const pluginIf = { featureFlags: { $contains: 'plugin-flag' } };
+    const plugin = createFrontendPlugin({
+      pluginId: 'test-plugin',
+      if: pluginIf,
+      extensions: [
+        createExtension({
+          name: 'one',
+          attachTo: { id: 'app', input: 'root' },
+          output: [dataRef],
+          factory: () => [dataRef('one')],
+        }),
+        createExtension({
+          name: 'two',
+          attachTo: { id: 'app', input: 'root' },
+          output: [dataRef],
+          factory: () => [dataRef('two')],
+        }),
+      ],
+    });
+
+    const specs = resolveAppNodeSpecs({
+      features: [plugin],
+      builtinExtensions: [],
+      parameters: [],
+      collector,
+    });
+
+    expect(specs).toHaveLength(2);
+    expect(specs[0].if).toEqual(pluginIf);
+    expect(specs[1].if).toEqual(pluginIf);
+  });
+
+  it('should merge plugin and module if predicates with extension predicates', () => {
+    const dataRef = createExtensionDataRef<string>().with({ id: 'test.data' });
+    const pluginIf = { featureFlags: { $contains: 'plugin-flag' } };
+    const moduleIf = { permissions: { $contains: 'module.permission' } };
+    const extensionIf = { featureFlags: { $contains: 'extension-flag' } };
+    const moduleExtensionIf = { featureFlags: { $contains: 'module-flag' } };
+    const plugin = createFrontendPlugin({
+      pluginId: 'test-plugin',
+      if: pluginIf,
+      extensions: [
+        createExtension({
+          name: 'plugin-extension',
+          attachTo: { id: 'app', input: 'root' },
+          if: extensionIf,
+          output: [dataRef],
+          factory: () => [dataRef('plugin')],
+        }),
+        createExtension({
+          name: 'module-extension',
+          attachTo: { id: 'app', input: 'root' },
+          output: [dataRef],
+          factory: () => [dataRef('base')],
+        }),
+      ],
+    });
+    const module = createFrontendModule({
+      pluginId: 'test-plugin',
+      if: moduleIf,
+      extensions: [
+        plugin.getExtension('test-plugin/module-extension').override({
+          if: moduleExtensionIf,
+          factory: () => [dataRef('module')],
+        }),
+      ],
+    });
+
+    const specs = resolveAppNodeSpecs({
+      features: [plugin, module],
+      builtinExtensions: [],
+      parameters: [],
+      collector,
+    });
+
+    expect(specs).toHaveLength(2);
+    expect(specs[0].id).toBe('test-plugin/plugin-extension');
+    expect(specs[0].if).toEqual({ $all: [pluginIf, extensionIf] });
+    expect(specs[1].id).toBe('test-plugin/module-extension');
+    expect(specs[1].if).toEqual({ $all: [moduleIf, moduleExtensionIf] });
+  });
 });

packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts

@@ -20,6 +20,7 @@ import {
   FrontendFeature,
   FrontendPlugin,
 } from '@backstage/frontend-plugin-api';
+import { FilterPredicate } from '@backstage/filter-predicates';
 import { ExtensionParameters } from './readAppExtensionsConfig';
 import { AppNodeSpec } from '@backstage/frontend-plugin-api';
 import { OpaqueFrontendPlugin } from '@internal/frontend';
@@ -40,6 +41,33 @@ function normalizePlugin(plugin: FrontendPlugin): FrontendPlugin {
   return plugin;
 }
 
+function combinePredicates(
+  left: FilterPredicate | undefined,
+  right: FilterPredicate | undefined,
+) {
+  if (!left) {
+    return right;
+  }
+  if (!right) {
+    return left;
+  }
+
+  return { $all: [left, right] };
+}
+
+function getExtensionPredicate(options: {
+  extension: Extension<any, any>;
+  internalExtension: ReturnType<typeof toInternalExtension>;
+}) {
+  if (options.extension.version === 'v2') {
+    return options.extension.if;
+  }
+  if (options.internalExtension.version === 'v2') {
+    return options.internalExtension.if;
+  }
+  return undefined;
+}
+
 /** @internal */
 export function resolveAppNodeSpecs(options: {
   features?: FrontendFeature[];
@@ -79,26 +107,41 @@ export function resolveAppNodeSpecs(options: {
   };
 
   const pluginExtensions = plugins.flatMap(plugin => {
-    return OpaqueFrontendPlugin.toInternal(plugin)
-      .extensions.map(extension => ({
+    const internalPlugin = OpaqueFrontendPlugin.toInternal(plugin);
+    return internalPlugin.extensions
+      .map(extension => ({
         ...extension,
         plugin,
+        if: combinePredicates(
+          internalPlugin.if,
+          extension.version === 'v2' ? extension.if : undefined,
+        ),
       }))
       .filter(filterForbidden);
   });
-  const moduleExtensions = modules.flatMap(mod =>
-    toInternalFrontendModule(mod)
-      .extensions.flatMap(extension => {
+  const moduleExtensions = modules.flatMap(mod => {
+    const internalModule = toInternalFrontendModule(mod);
+    return internalModule.extensions
+      .flatMap(extension => {
         // Modules for plugins that are not installed are ignored
         const plugin = plugins.find(p => p.pluginId === mod.pluginId);
         if (!plugin) {
           return [];
         }
 
-        return [{ ...extension, plugin }];
+        return [
+          {
+            ...extension,
+            plugin,
+            if: combinePredicates(
+              internalModule.if,
+              extension.version === 'v2' ? extension.if : undefined,
+            ),
+          },
+        ];
       })
-      .filter(filterForbidden),
-  );
+      .filter(filterForbidden);
+  });
 
   const appPlugin =
     plugins.find(plugin => plugin.pluginId === 'app') ??
@@ -116,10 +159,7 @@ export function resolveAppNodeSpecs(options: {
           source: plugin,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
-          if:
-            internalExtension.version === 'v2'
-              ? internalExtension.if
-              : undefined,
+          if: getExtensionPredicate({ extension, internalExtension }),
           config: undefined as unknown,
         },
       };
@@ -133,10 +173,7 @@ export function resolveAppNodeSpecs(options: {
           plugin: appPlugin,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
-          if:
-            internalExtension.version === 'v2'
-              ? internalExtension.if
-              : undefined,
+          if: getExtensionPredicate({ extension, internalExtension }),
           config: undefined as unknown,
         },
       };
@@ -156,8 +193,10 @@ export function resolveAppNodeSpecs(options: {
       configuredExtensions[index].extension = internalExtension;
       configuredExtensions[index].params.attachTo = internalExtension.attachTo;
       configuredExtensions[index].params.disabled = internalExtension.disabled;
-      configuredExtensions[index].params.if =
-        internalExtension.version === 'v2' ? internalExtension.if : undefined;
+      configuredExtensions[index].params.if = getExtensionPredicate({
+        extension,
+        internalExtension,
+      });
     } else {
       // Add the extension as a new one when not overriding an existing one
       configuredExtensions.push({
@@ -167,10 +206,7 @@ export function resolveAppNodeSpecs(options: {
           source: extension.plugin,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
-          if:
-            internalExtension.version === 'v2'
-              ? internalExtension.if
-              : undefined,
+          if: getExtensionPredicate({ extension, internalExtension }),
           config: undefined,
         },
       });