fix(@angular/cli): enhance list_projects MCP tool file system traversal and symlink handling

This commit introduces several improvements to the `findAngularJsonFiles` function within the `list_projects` tool.
An `isIgnorableFileError` helper was introduced to consistently handle file system errors (EACCES, EPERM, ENOENT, EBUSY) across `stat` and `readdir` calls, making the traversal more resilient to transient issues and unavailable directories.
A check was implemented to ensure that symbolic links are only traversed if their resolved target paths are valid and remain within the defined search roots.

Author: clydin

packages/angular/cli/src/commands/mcp/tools/projects.ts

@@ -6,8 +6,9 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
+import { realpathSync } from 'node:fs';
 import { readFile, readdir, stat } from 'node:fs/promises';
-import { dirname, extname, join, normalize, posix, resolve } from 'node:path';
+import { dirname, extname, isAbsolute, join, normalize, posix, relative, resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import semver from 'semver';
 import { z } from 'zod';
@@ -148,15 +149,24 @@ their types, and their locations.
 });
 
 const EXCLUDED_DIRS = new Set(['node_modules', 'dist', 'out', 'coverage']);
+const IGNORED_FILE_SYSTEM_ERRORS = new Set(['EACCES', 'EPERM', 'ENOENT', 'EBUSY']);
+
+function isIgnorableFileError(error: Error & { code?: string }): boolean {
+  return !!error.code && IGNORED_FILE_SYSTEM_ERRORS.has(error.code);
+}
 
 /**
  * Iteratively finds all 'angular.json' files with controlled concurrency and directory exclusions.
  * This non-recursive implementation is suitable for very large directory trees,
  * prevents file descriptor exhaustion (`EMFILE` errors), and handles symbolic link loops.
  * @param rootDir The directory to start the search from.
+ * @param allowedRealRoots A list of allowed real root directories (resolved paths) to restrict symbolic link traversal.
  * @returns An async generator that yields the full path of each found 'angular.json' file.
  */
-async function* findAngularJsonFiles(rootDir: string): AsyncGenerator<string> {
+async function* findAngularJsonFiles(
+  rootDir: string,
+  allowedRealRoots: ReadonlyArray<string>,
+): AsyncGenerator<string> {
   const CONCURRENCY_LIMIT = 50;
   const queue: string[] = [rootDir];
   const seenInodes = new Set<number>();
@@ -166,7 +176,7 @@ async function* findAngularJsonFiles(rootDir: string): AsyncGenerator<string> {
     seenInodes.add(rootStats.ino);
   } catch (error) {
     assertIsError(error);
-    if (error.code === 'EACCES' || error.code === 'EPERM' || error.code === 'ENOENT') {
+    if (isIgnorableFileError(error)) {
       return; // Cannot access root, so there's nothing to do.
     }
     throw error;
@@ -182,25 +192,46 @@ async function* findAngularJsonFiles(rootDir: string): AsyncGenerator<string> {
         const subdirectories: string[] = [];
         for (const entry of entries) {
           const fullPath = join(dir, entry.name);
-          if (entry.isDirectory()) {
+          if (entry.isDirectory() || entry.isSymbolicLink()) {
             // Exclude dot-directories, build/cache directories, and node_modules
             if (entry.name.startsWith('.') || EXCLUDED_DIRS.has(entry.name)) {
               continue;
             }
 
-            // Check for symbolic link loops
+            let entryStats;
             try {
-              const entryStats = await stat(fullPath);
+              entryStats = await stat(fullPath);
               if (seenInodes.has(entryStats.ino)) {
                 continue; // Already visited this directory (symlink loop), skip.
               }
-              seenInodes.add(entryStats.ino);
             } catch {
               // Ignore errors from stat (e.g., broken symlinks)
               continue;
             }
 
-            subdirectories.push(fullPath);
+            if (entry.isSymbolicLink()) {
+              try {
+                const targetPath = realpathSync(fullPath);
+                // Ensure the link target is within one of the allowed roots.
+                const isAllowed = allowedRealRoots.some((root) => {
+                  const rel = relative(root, targetPath);
+
+                  return !rel.startsWith('..') && !isAbsolute(rel);
+                });
+
+                if (!isAllowed) {
+                  continue;
+                }
+              } catch {
+                // Ignore broken links.
+                continue;
+              }
+            }
+
+            if (entryStats.isDirectory()) {
+              seenInodes.add(entryStats.ino);
+              subdirectories.push(fullPath);
+            }
           } else if (entry.name === 'angular.json') {
             foundFilesInBatch.push(fullPath);
           }
@@ -209,7 +240,7 @@ async function* findAngularJsonFiles(rootDir: string): AsyncGenerator<string> {
         return subdirectories;
       } catch (error) {
         assertIsError(error);
-        if (error.code === 'EACCES' || error.code === 'EPERM') {
+        if (isIgnorableFileError(error)) {
           return []; // Silently ignore permission errors.
         }
         throw error;
@@ -529,8 +560,20 @@ async function createListProjectsHandler({ server }: McpToolContext) {
       searchRoots = [process.cwd()];
     }
 
+    // Pre-resolve allowed roots to handle their own symlinks or normalizations.
+    // We ignore failures here; if a root is broken, we simply won't match against it.
+    const realAllowedRoots = searchRoots
+      .map((r) => {
+        try {
+          return realpathSync(r);
+        } catch {
+          return null;
+        }
+      })
+      .filter((r): r is string => r !== null);
+
     for (const root of searchRoots) {
-      for await (const configFile of findAngularJsonFiles(root)) {
+      for await (const configFile of findAngularJsonFiles(root, realAllowedRoots)) {
         const { workspace, parsingError, versioningError } = await processConfigFile(
           configFile,
           root,