Merge branch 'master' into runtime-module-federation-enablement

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

packages/cli/CHANGELOG.md

@@ -1,5 +1,50 @@
 # @backstage/cli
 
+## 0.35.4-next.2
+
+### Patch Changes
+
+- 20131c5: Added support for CSS exports in package builds. When a package declares a CSS file in its `exports` field (e.g., `"./styles.css": "./src/styles.css"`), the CLI will automatically bundle it during `backstage-cli package build`, resolving any `@import` statements. The export path is rewritten from `src/` to `dist/` at publish time.
+
+  Fixed `backstage-cli repo fix` to not add `typesVersions` entries for non-script exports like CSS files.
+
+- 6ce4a13: Removed `/alpha` from `scaffolderActionsExtensionPoint` import
+- 73351c2: Updated dependency `webpack` to `~5.104.0`.
+- Updated dependencies
+  - @backstage/integration@1.20.0-next.2
+  - @backstage/cli-node@0.2.18-next.1
+  - @backstage/config-loader@1.10.8-next.0
+
+## 0.35.4-next.1
+
+### Patch Changes
+
+- 5e3ef57: Added support for the new `peerModules` metadata field in `package.json`. This field allows plugin packages to declare modules that should be installed alongside them for cross-plugin integrations. The field is validated by `backstage-cli repo fix --publish`.
+- Updated dependencies
+  - @backstage/integration@1.20.0-next.1
+  - @backstage/cli-node@0.2.18-next.1
+
+## 0.35.3-next.0
+
+### Patch Changes
+
+- cfd8103: Updated catalog provider module template to use stable catalog extension points from `@backstage/plugin-catalog-node` instead of alpha exports.
+- 7455dae: Use node prefix on native imports
+- 4fc7bf0: Bump to tar v7
+- 122d39c: Completely removed support for the deprecated `app.experimental.packages` configuration. Replace existing usage directly with `app.packages`.
+- 69d880e: Bump to latest zod to ensure it has the latest features
+- Updated dependencies
+  - @backstage/config-loader@1.10.8-next.0
+  - @backstage/eslint-plugin@0.2.1-next.0
+  - @backstage/integration@1.19.3-next.0
+  - @backstage/cli-common@0.1.18-next.0
+  - @backstage/cli-node@0.2.17-next.0
+  - @backstage/catalog-model@1.7.6
+  - @backstage/config@1.3.6
+  - @backstage/errors@1.2.7
+  - @backstage/release-manifests@0.0.13
+  - @backstage/types@1.2.2
+
 ## 0.35.2
 
 ### Patch Changes

packages/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@backstage/cli",
-  "version": "0.35.2",
+  "version": "0.35.4-next.2",
   "description": "CLI for developing Backstage plugins and apps",
   "backstage": {
     "role": "cli"
@@ -119,6 +119,7 @@
     "p-queue": "^6.6.2",
     "pirates": "^4.0.6",
     "postcss": "^8.1.0",
+    "postcss-import": "^16.1.0",
     "process": "^0.11.10",
     "raw-loader": "^4.0.2",
     "react-dev-utils": "^12.0.0-next.60",
@@ -192,7 +193,7 @@
     "msw": "^1.0.0",
     "nodemon": "^3.0.1",
     "terser-webpack-plugin": "^5.1.3",
-    "webpack": "~5.103.0",
+    "webpack": "~5.104.0",
     "webpack-dev-server": "^5.0.0"
   },
   "peerDependencies": {
@@ -207,7 +208,7 @@
     "jsdom": "^27.1.0",
     "mini-css-extract-plugin": "^2.4.2",
     "terser-webpack-plugin": "^5.1.3",
-    "webpack": "~5.103.0",
+    "webpack": "~5.104.0",
     "webpack-dev-server": "^5.0.0"
   },
   "peerDependenciesMeta": {

packages/cli/src/lib/entryPoints.ts

@@ -33,18 +33,25 @@ const defaultIndex = {
   ext: '.ts',
 };
 
+const SCRIPT_EXTS = ['.js', '.jsx', '.ts', '.tsx'];
+
 function parseEntryPoint(mount: string, path: string): EntryPoint {
+  const ext = extname(path);
+
   let name = mount;
   if (name === '.') {
     name = 'index';
   } else if (name.startsWith('./')) {
     name = name.slice(2);
   }
-  if (name.includes('/')) {
+
+  // Script entry points can't have slashes because we create backward-compat
+  // directories for them. Non-script files (like CSS) can have nested paths.
+  if (name.includes('/') && SCRIPT_EXTS.includes(ext)) {
     throw new Error(`Mount point '${mount}' may not contain multiple slashes`);
   }
 
-  return { mount, path, name, ext: extname(path) };
+  return { mount, path, name, ext };
 }
 
 export function readEntryPoints(pkg: BackstagePackageJson): Array<EntryPoint> {

packages/cli/src/modules/build/commands/package/build/command.ts

@@ -15,9 +15,14 @@
  */
 
 import { OptionValues } from 'commander';
+import fs from 'fs-extra';
 import { buildPackage, Output } from '../../../lib/builder';
 import { findRoleFromCommand } from '../../../../../lib/role';
-import { PackageGraph, PackageRoles } from '@backstage/cli-node';
+import {
+  BackstagePackageJson,
+  PackageGraph,
+  PackageRoles,
+} from '@backstage/cli-node';
 import { paths } from '../../../../../lib/paths';
 import { buildFrontend } from '../../../lib/buildFrontend';
 import { buildBackend } from '../../../lib/buildBackend';
@@ -93,8 +98,13 @@ export async function command(opts: OptionValues): Promise<void> {
     outputs.add(Output.types);
   }
 
+  const packageJson = (await fs.readJson(
+    paths.resolveTarget('package.json'),
+  )) as BackstagePackageJson;
+
   return buildPackage({
     outputs,
+    packageJson,
     minify: Boolean(opts.minify),
     workspacePackages: await PackageGraph.listTargetPackages(),
   });

packages/cli/src/modules/build/lib/builder/config.ts

@@ -37,7 +37,7 @@ import {
   OutputPlugin,
 } from 'rollup';
 
-import { forwardFileImports } from './plugins';
+import { forwardFileImports, cssEntryPoints } from './plugins';
 import { BuildOptions, Output } from './types';
 import { paths } from '../../../../lib/paths';
 import { BackstagePackageJson } from '@backstage/cli-node';
@@ -275,6 +275,7 @@ export async function makeRollupConfigs(
           target: 'ES2023',
           minify: options.minify,
         }),
+        cssEntryPoints({ entryPoints, targetDir }),
       ],
     });
   }

packages/cli/src/modules/build/lib/builder/packager.ts

@@ -107,7 +107,8 @@ export const buildPackage = async (options: BuildOptions) => {
 
   const rollupConfigs = await makeRollupConfigs(options);
 
-  await fs.remove(resolvePath(options.targetDir ?? paths.targetDir, 'dist'));
+  const targetDir = options.targetDir ?? paths.targetDir;
+  await fs.remove(resolvePath(targetDir, 'dist'));
 
   const buildTasks = rollupConfigs.map(rollupBuild);
 

packages/cli/src/modules/build/lib/builder/plugins.test.ts

@@ -22,9 +22,25 @@ import {
   PluginContext,
 } from 'rollup';
 
-import { forwardFileImports } from './plugins';
+import { forwardFileImports, cssEntryPoints } from './plugins';
 import { createMockDirectory } from '@backstage/backend-test-utils';
 
+// Helper to call generateBundle hook which can be a function or ObjectHook
+async function callGenerateBundle(
+  plugin: ReturnType<typeof cssEntryPoints>,
+  ctx: PluginContext,
+  options: NormalizedOutputOptions,
+  bundle: Record<string, OutputChunk | OutputAsset>,
+  isWrite: boolean,
+) {
+  const hook = plugin.generateBundle;
+  if (typeof hook === 'function') {
+    await hook.call(ctx, options, bundle, isWrite);
+  } else if (hook && typeof hook === 'object' && 'handler' in hook) {
+    await hook.handler.call(ctx, options, bundle, isWrite);
+  }
+}
+
 const context = {
   meta: {
     rollupVersion: '0.0.0',
@@ -194,3 +210,139 @@ describe('forwardFileImports', () => {
     });
   });
 });
+
+describe('cssEntryPoints', () => {
+  it('should be created with correct name', () => {
+    const plugin = cssEntryPoints({
+      entryPoints: [],
+      targetDir: '/dev',
+    });
+    expect(plugin.name).toBe('backstage-css-entry-points');
+  });
+
+  describe('with createMockDirectory', () => {
+    const mockDir = createMockDirectory();
+
+    const emittedFiles: Array<{ fileName: string; source: string }> = [];
+    const emitContext = {
+      ...context,
+      emitFile: (file: { fileName: string; source: string }) => {
+        emittedFiles.push(file);
+        return 'asset-id';
+      },
+    } as unknown as PluginContext;
+
+    beforeEach(() => {
+      emittedFiles.length = 0;
+      mockDir.setContent({
+        dev: {
+          src: {
+            css: {
+              'styles.css': '@import "./base.css";\n.root { color: red; }',
+              'base.css': '.base { margin: 0; }',
+            },
+          },
+        },
+      });
+    });
+
+    it('should not emit when isWrite is false', async () => {
+      const plugin = cssEntryPoints({
+        entryPoints: [
+          {
+            mount: './css/styles.css',
+            path: './src/css/styles.css',
+            name: 'css/styles.css',
+            ext: '.css',
+          },
+        ],
+        targetDir: mockDir.resolve('dev'),
+      });
+
+      await callGenerateBundle(
+        plugin,
+        emitContext,
+        { dir: mockDir.resolve('dev/dist') } as NormalizedOutputOptions,
+        {},
+        false,
+      );
+
+      expect(emittedFiles).toHaveLength(0);
+    });
+
+    it('should emit only CSS entry points with resolved imports', async () => {
+      const plugin = cssEntryPoints({
+        entryPoints: [
+          // Non-CSS entry should be ignored
+          { mount: '.', path: './src/index.ts', name: 'index', ext: '.ts' },
+          {
+            mount: './css/styles.css',
+            path: './src/css/styles.css',
+            name: 'css/styles.css',
+            ext: '.css',
+          },
+        ],
+        targetDir: mockDir.resolve('dev'),
+      });
+
+      await callGenerateBundle(
+        plugin,
+        emitContext,
+        { dir: mockDir.resolve('dev/dist') } as NormalizedOutputOptions,
+        {},
+        true,
+      );
+
+      // Only CSS file should be emitted, not the .ts entry
+      expect(emittedFiles).toHaveLength(1);
+      expect(emittedFiles[0].fileName).toBe('css/styles.css');
+      expect(emittedFiles[0].source).toContain('.base { margin: 0; }');
+      expect(emittedFiles[0].source).toContain('.root { color: red; }');
+      expect(emittedFiles[0].source).not.toContain('@import');
+    });
+
+    it('should only emit once per output directory', async () => {
+      const plugin = cssEntryPoints({
+        entryPoints: [
+          {
+            mount: './css/styles.css',
+            path: './src/css/styles.css',
+            name: 'css/styles.css',
+            ext: '.css',
+          },
+        ],
+        targetDir: mockDir.resolve('dev'),
+      });
+
+      // First call should emit
+      await callGenerateBundle(
+        plugin,
+        emitContext,
+        { dir: mockDir.resolve('dev/dist') } as NormalizedOutputOptions,
+        {},
+        true,
+      );
+      expect(emittedFiles).toHaveLength(1);
+
+      // Second call to same dir should not emit again
+      await callGenerateBundle(
+        plugin,
+        emitContext,
+        { dir: mockDir.resolve('dev/dist') } as NormalizedOutputOptions,
+        {},
+        true,
+      );
+      expect(emittedFiles).toHaveLength(1);
+
+      // Call to different dir should emit
+      await callGenerateBundle(
+        plugin,
+        emitContext,
+        { dir: mockDir.resolve('dev/dist2') } as NormalizedOutputOptions,
+        {},
+        true,
+      );
+      expect(emittedFiles).toHaveLength(2);
+    });
+  });
+});

packages/cli/src/modules/build/lib/builder/plugins.ts

@@ -15,6 +15,8 @@
  */
 
 import fs from 'fs-extra';
+import postcss from 'postcss';
+import postcssImport from 'postcss-import';
 import {
   dirname,
   resolve as resolvePath,
@@ -27,6 +29,7 @@ import {
   OutputChunk,
   HasModuleSideEffects,
 } from 'rollup';
+import { EntryPoint } from '../../../../lib/entryPoints';
 
 type ForwardFileImportsOptions = {
   include: Array<string | RegExp> | string | RegExp | null;
@@ -169,3 +172,58 @@ export function forwardFileImports(options: ForwardFileImportsOptions) {
     },
   } satisfies Plugin;
 }
+
+interface CssEntryPointsOptions {
+  entryPoints: EntryPoint[];
+  targetDir: string;
+}
+
+/**
+ * Rollup plugin that bundles CSS entry points using postcss-import.
+ * CSS files declared in package.json exports are processed and emitted
+ * as part of the Rollup bundle.
+ */
+export function cssEntryPoints(options: CssEntryPointsOptions): Plugin {
+  const cssEntries = options.entryPoints.filter(ep => ep.ext === '.css');
+
+  // Track output directories we've already emitted CSS to, to avoid duplicates
+  // when Rollup runs generateBundle multiple times (once per output format)
+  const generatedFor = new Set<string>();
+
+  return {
+    name: 'backstage-css-entry-points',
+
+    async generateBundle(outputOptions, _bundle, isWrite) {
+      if (!isWrite) {
+        return;
+      }
+
+      const dir = outputOptions.dir || dirname(outputOptions.file!);
+      if (generatedFor.has(dir)) {
+        return;
+      }
+      generatedFor.add(dir);
+
+      for (const entryPoint of cssEntries) {
+        const sourcePath = resolvePath(options.targetDir, entryPoint.path);
+        // Strip the src/ prefix to create an output filename relative to the Rollup output directory
+        const outputPath = entryPoint.path.replace(/^(\.\/)?src\//, '');
+
+        // Read source CSS
+        const source = await fs.readFile(sourcePath, 'utf8');
+
+        // Bundle @import statements using postcss-import
+        const result = await postcss([postcssImport()]).process(source, {
+          from: sourcePath,
+        });
+
+        // Emit the bundled CSS as an asset
+        this.emitFile({
+          type: 'asset',
+          fileName: outputPath,
+          source: result.css,
+        });
+      }
+    },
+  };
+}

packages/cli/src/modules/build/lib/packager/productionPack.ts

@@ -148,7 +148,11 @@ async function rewriteEntryPoints(
 
   for (const entryPoint of entryPoints) {
     if (!SCRIPT_EXTS.includes(entryPoint.ext)) {
-      outputExports[entryPoint.mount] = entryPoint.path;
+      // Non-script files (like CSS) get their paths rewritten from src/ to dist/
+      outputExports[entryPoint.mount] = entryPoint.path.replace(
+        /^(\.\/)?src\//,
+        './dist/',
+      );
       continue;
     }
 

packages/cli/src/modules/maintenance/commands/repo/fix.ts

@@ -27,10 +27,13 @@ import {
   resolve as resolvePath,
   posix,
   relative as relativePath,
+  extname,
 } from 'node:path';
 import { paths } from '../../../../lib/paths';
 import { publishPreflightCheck } from '../../lib/publishing';
 
+const SCRIPT_EXTS = ['.js', '.jsx', '.ts', '.tsx', '.json'];
+
 /**
  * A mutable object representing a package.json file with potential fixes.
  */
@@ -122,29 +125,46 @@ export function fixPackageExports(pkg: FixablePackage) {
     }
     const newPath = trimRelative(path);
 
+    // Only script files and package.json should be added to typesVersions
     if (typeof value === 'string') {
-      typeEntries[newPath] = [trimRelative(value)];
+      if (SCRIPT_EXTS.includes(extname(value))) {
+        typeEntries[newPath] = [trimRelative(value)];
+      }
     } else if (value && typeof value === 'object' && !Array.isArray(value)) {
       if (typeof value.types === 'string') {
         typeEntries[newPath] = [trimRelative(value.types)];
-      } else if (typeof value.default === 'string') {
+      } else if (
+        typeof value.default === 'string' &&
+        SCRIPT_EXTS.includes(extname(value.default))
+      ) {
         typeEntries[newPath] = [trimRelative(value.default)];
       }
     }
   }
 
-  const typesVersions = { '*': typeEntries };
-  if (existingTypesVersions !== JSON.stringify(typesVersions)) {
-    const newPkgEntries = Object.entries(pkg.packageJson).filter(
-      ([name]) => name !== 'typesVersions',
-    );
-    newPkgEntries.splice(
-      newPkgEntries.findIndex(([name]) => name === 'exports') + 1,
-      0,
-      ['typesVersions', typesVersions],
-    );
+  const hasTypeEntries = Object.keys(typeEntries).length > 0;
+  const typesVersions = hasTypeEntries ? { '*': typeEntries } : undefined;
 
-    pkg.packageJson = Object.fromEntries(newPkgEntries) as BackstagePackageJson;
+  if (existingTypesVersions !== JSON.stringify(typesVersions)) {
+    if (pkg.packageJson.typesVersions) {
+      // Update in place to preserve field order
+      if (typesVersions) {
+        pkg.packageJson.typesVersions = typesVersions;
+      } else {
+        delete pkg.packageJson.typesVersions;
+      }
+    } else if (typesVersions) {
+      // Insert after exports when adding for the first time
+      const newPkgEntries = Object.entries(pkg.packageJson);
+      newPkgEntries.splice(
+        newPkgEntries.findIndex(([name]) => name === 'exports') + 1,
+        0,
+        ['typesVersions', typesVersions],
+      );
+      pkg.packageJson = Object.fromEntries(
+        newPkgEntries,
+      ) as BackstagePackageJson;
+    }
     pkg.changed = true;
   }
 
@@ -430,6 +450,47 @@ export function fixPluginPackages(
   }
 }
 
+export function fixPeerModules(pkg: FixablePackage) {
+  const pkgBackstage = pkg.packageJson.backstage;
+  const role = pkgBackstage?.role;
+  if (!role) {
+    return;
+  }
+
+  const peerModules = pkgBackstage.peerModules;
+  if (peerModules === undefined) {
+    return;
+  }
+
+  const packagePath = relativePath(
+    paths.targetRoot,
+    resolvePath(pkg.dir, 'package.json'),
+  );
+
+  // Validate that peerModules is only used on plugin packages
+  if (role !== 'backend-plugin' && role !== 'frontend-plugin') {
+    throw new Error(
+      `The 'backstage.peerModules' field in "${pkg.packageJson.name}" can only be used on plugin packages (backend-plugin or frontend-plugin), but package has role '${role}' in "${packagePath}"`,
+    );
+  }
+
+  // Validate that peerModules is an array
+  if (!Array.isArray(peerModules)) {
+    throw new Error(
+      `Invalid 'backstage.peerModules' field in "${pkg.packageJson.name}", must be an array of package names in "${packagePath}"`,
+    );
+  }
+
+  // Validate that all entries are non-empty strings
+  for (const entry of peerModules) {
+    if (typeof entry !== 'string' || entry.length === 0) {
+      throw new Error(
+        `Invalid entry in 'backstage.peerModules' field in "${pkg.packageJson.name}", all entries must be non-empty package name strings in "${packagePath}"`,
+      );
+    }
+  }
+}
+
 type PackageFixer = (pkg: FixablePackage, packages: FixablePackage[]) => void;
 
 export async function command(opts: OptionValues): Promise<void> {
@@ -444,6 +505,7 @@ export async function command(opts: OptionValues): Promise<void> {
       fixRepositoryField,
       fixPluginId,
       fixPluginPackages,
+      fixPeerModules,
       // Run the publish preflight check too, to make sure we don't uncover errors during publishing
       publishPreflightCheck,
     );

packages/cli/src/types.d.ts

@@ -259,3 +259,9 @@ declare module 'webpack-node-externals' {
 }
 
 declare module '@esbuild-kit/cjs-loader' {}
+
+declare module 'postcss-import' {
+  import { Plugin } from 'postcss';
+
+  export default function postcssImport(): Plugin;
+}

packages/cli/templates/scaffolder-backend-module/src/module.ts

@@ -1,5 +1,5 @@
 import { createBackendModule } from "@backstage/backend-plugin-api";
-import { scaffolderActionsExtensionPoint  } from '@backstage/plugin-scaffolder-node/alpha';
+import { scaffolderActionsExtensionPoint  } from '@backstage/plugin-scaffolder-node';
 import { createExampleAction } from "./actions/example";
 
 /**