feat(builder): Add a cachePath option for the federation cache

src/builders/build/builder.ts

@@ -36,7 +36,6 @@ import {
 import {
   AbortedError,
   createNfWatcher,
-  getDefaultCachePath,
   linkedSharedDirs,
   logger,
   type NfFileWatcher,
@@ -52,6 +51,7 @@ import { checkForInvalidImports } from "./../../utils/check-for-invalid-imports.
 import { warnFlatExternals } from "./../../utils/warn-flat-externals.js";
 import { federationSourceFiles } from "./../../utils/federation-source-files.js";
 import { watchpackWatch } from "./../../utils/watchpack-watch.js";
+import { resolveCachePath } from "./../../utils/resolve-cache-path.js";
 import { federationBuildNotifier } from "./federation-build-notifier.js";
 import {
   createFederationFreshness,
@@ -256,7 +256,7 @@ export async function* runBuilder(
         i18n ? getLocaleSubPath(i18n, localeFilter[0]!) : localeFilter[0]!,
       );
 
-  const cachePath = getDefaultCachePath(context.workspaceRoot);
+  const cachePath = resolveCachePath(context.workspaceRoot, nfBuilderOptions.cachePath);
 
   const normalized = await normalizeFederationOptions(
     {

src/builders/build/schema.d.ts

@@ -23,6 +23,7 @@ export interface NfBuilderSchema extends JsonObject {
   devServer?: boolean;
   entryPoints?: string[];
   cacheExternalArtifacts?: boolean;
+  cachePath?: string;
 }
 
 export type NfInternalOptions = {

src/builders/build/schema.json

@@ -81,6 +81,10 @@
       "description": "Will cache the shared externals so they can be re-used between builds",
       "alias": "cache"
     },
+    "cachePath": {
+      "type": "string",
+      "description": "Folder for the federation cache, relative to the workspace root. Defaults to 'node_modules/.cache/native-federation'. Avoid '.angular/cache' (Angular purges it); use e.g. '.angular/nf-cache' and gitignore it."
+    },
     "buildNotifications": {
       "type": "object",
       "description": "Opt in to build completion notifications. Omitting this option leaves them off; the defaults below only apply once it is present.",

src/builders/remote/builder.ts

@@ -22,7 +22,6 @@ import {
   setLogLevel,
   RebuildQueue,
   AbortedError,
-  getDefaultCachePath,
   syncNfFileWatcher,
   linkedSharedDirs,
   sharedMappingDirs,
@@ -33,6 +32,7 @@ import { withDiskCaseWorkspaceRoot } from '../../utils/disk-case.js';
 import { checkForInvalidImports } from '../../utils/check-for-invalid-imports.js';
 import { warnFlatExternals } from '../../utils/warn-flat-externals.js';
 import { federationSourceFiles } from '../../utils/federation-source-files.js';
+import { resolveCachePath } from '../../utils/resolve-cache-path.js';
 
 import type { NfRemoteBuilderSchema, NfRemoteInternalOptions } from './schema.js';
 import { resolveNgBuilderOptions } from './resolve-ng-options.js';
@@ -89,7 +89,7 @@ export async function* runRemoteBuilder(
   setBuildAdapter(adapter);
   setLogLevel(nfBuilderOptions.verbose ? 'verbose' : 'info');
 
-  const cachePath = getDefaultCachePath(context.workspaceRoot);
+  const cachePath = resolveCachePath(context.workspaceRoot, nfBuilderOptions.cachePath);
 
   const normalized = await normalizeFederationOptions(
     {

src/builders/remote/schema.d.ts

@@ -13,6 +13,7 @@ export interface NfRemoteBuilderSchema extends JsonObject {
   verbose?: boolean;
   entryPoints?: string[];
   cacheExternalArtifacts?: boolean;
+  cachePath?: string;
 
   // Passthroughs to the Angular esbuild pipeline / asset copier.
   assets?: ApplicationBuilderOptions['assets'];

src/builders/remote/schema.json

@@ -50,6 +50,10 @@
       "description": "Will cache the shared externals so they can be re-used between builds",
       "alias": "cache"
     },
+    "cachePath": {
+      "type": "string",
+      "description": "Folder for the federation cache, relative to the workspace root. Defaults to 'node_modules/.cache/native-federation'. Avoid '.angular/cache' (Angular purges it); use e.g. '.angular/nf-cache' and gitignore it."
+    },
     "assets": {
       "type": "array",
       "description": "Assets to copy into the output directory. Same shape as @angular/build:application 'assets'.",

src/utils/resolve-cache-path.spec.ts

@@ -0,0 +1,48 @@
+import * as path from 'path';
+
+import { resolveCachePath } from './resolve-cache-path.js';
+
+const root = path.resolve('/workspace/app');
+
+describe('resolveCachePath', () => {
+  it('falls back to core default when unset or empty', () => {
+    expect(resolveCachePath(root)).toBe(path.join(root, 'node_modules/.cache/native-federation'));
+    expect(resolveCachePath(root, '')).toBe(
+      path.join(root, 'node_modules/.cache/native-federation')
+    );
+  });
+
+  it('resolves a relative path against the workspace root', () => {
+    expect(resolveCachePath(root, '.angular/nf-cache')).toBe(path.join(root, '.angular/nf-cache'));
+  });
+
+  it('keeps an absolute path as is', () => {
+    const abs = path.resolve('/tmp/nf-cache');
+    expect(resolveCachePath(root, abs)).toBe(abs);
+  });
+
+  it('normalizes ".." segments, allowing a folder outside the workspace', () => {
+    expect(resolveCachePath(root, '../shared-cache/nf')).toBe(
+      path.resolve('/workspace/shared-cache/nf')
+    );
+  });
+
+  it('accepts a sibling whose name merely starts with ".."', () => {
+    // path.relative(root/..foo, root) is "..": a plain prefix check on ".." would misread
+    // names like this, so the helper compares whole segments.
+    expect(resolveCachePath(root, '..foo')).toBe(path.join(root, '..foo'));
+  });
+
+  it('rejects an ancestor whose child folder name starts with ".."', () => {
+    const odd = path.resolve('/workspace/..hidden/app');
+    expect(() => resolveCachePath(odd, '..')).toThrow(/contains the workspace root/);
+  });
+
+  // Core rm -rf's <cachePath>/<project> on an adapter minor bump; these would hit sources.
+  it.each(['.', './', '..', '../..', root, path.resolve('/')])(
+    'rejects %s, which contains the workspace root',
+    cachePath => {
+      expect(() => resolveCachePath(root, cachePath)).toThrow(/contains the workspace root/);
+    }
+  );
+});

src/utils/resolve-cache-path.ts

@@ -0,0 +1,24 @@
+import * as path from 'path';
+
+import { getDefaultCachePath } from '@softarc/native-federation/internal';
+
+export function resolveCachePath(workspaceRoot: string, cachePath?: string): string {
+  if (!cachePath) {
+    return getDefaultCachePath(workspaceRoot);
+  }
+
+  const resolved = path.resolve(workspaceRoot, cachePath);
+
+  // Core purges `<cachePath>/<project>` whenever the adapter's minor changes, so a cachePath
+  // at or above the workspace root could delete a source folder named like the project.
+  const up = path.relative(resolved, workspaceRoot);
+  const isOutside = up === '..' || up.startsWith(`..${path.sep}`) || path.isAbsolute(up);
+  if (!isOutside) {
+    throw new Error(
+      `The cachePath "${cachePath}" resolves to "${resolved}", which contains the workspace ` +
+        `root. Point it at a dedicated folder, e.g. ".angular/nf-cache".`
+    );
+  }
+
+  return resolved;
+}