fix(ivy): ngcc - handle pathMappings to files rather then directories (#30525)

Paths can be mapped directly to files, which was not being taken
into account when computing `basePaths` for the `EntryPointFinder`s.

Now if a `pathMapping` pattern does not exist or is a file, then we try
the containing folder instead.

Fixes #31424

PR Close #30525

packages/compiler-cli/ngcc/src/entry_point_finder/utils.ts

@@ -5,7 +5,7 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {AbsoluteFsPath, join, resolve} from '../../../src/ngtsc/file_system';
+import {AbsoluteFsPath, getFileSystem, join, resolve} from '../../../src/ngtsc/file_system';
 import {PathMappings} from '../utils';
 
 /**
@@ -29,11 +29,17 @@ import {PathMappings} from '../utils';
  */
 export function getBasePaths(
     sourceDirectory: AbsoluteFsPath, pathMappings: PathMappings | undefined): AbsoluteFsPath[] {
-  const basePaths = [sourceDirectory];
+  const fs = getFileSystem();
+  let basePaths = [sourceDirectory];
   if (pathMappings) {
     const baseUrl = resolve(pathMappings.baseUrl);
     Object.values(pathMappings.paths).forEach(paths => paths.forEach(path => {
-      basePaths.push(join(baseUrl, extractPathPrefix(path)));
+      // We only want base paths that exist and are not files
+      let basePath = join(baseUrl, extractPathPrefix(path));
+      while (basePath !== baseUrl && (!fs.exists(basePath) || fs.stat(basePath).isFile())) {
+        basePath = fs.dirname(basePath);
+      }
+      basePaths.push(basePath);
     }));
   }
   basePaths.sort();  // Get the paths in order with the shorter ones first.

packages/compiler-cli/ngcc/test/entry_point_finder/directory_walker_entry_point_finder_spec.ts

@@ -166,6 +166,30 @@ runInEachFileSystem(() => {
         ]);
       });
 
+      it('should handle pathMappings that map to files or non-existent directories', () => {
+        const basePath = _Abs('/path_mapped/node_modules');
+        const pathMappings: PathMappings = {
+          baseUrl: '/path_mapped/dist',
+          paths: {
+            '@test': ['pkg2/fesm2015/pkg2.js'],
+            '@missing': ['pkg3'],
+          }
+        };
+        loadTestFiles([
+          ...createPackage(_Abs('/path_mapped/node_modules'), 'test', []),
+          ...createPackage(_Abs('/path_mapped/dist'), 'pkg2'),
+        ]);
+        resolver = new DependencyResolver(
+            fs, logger, {esm2015: new EsmDependencyHost(fs, new ModuleResolver(fs, pathMappings))});
+        const finder = new DirectoryWalkerEntryPointFinder(
+            fs, config, logger, resolver, basePath, pathMappings);
+        const {entryPoints} = finder.findEntryPoints();
+        expect(dumpEntryPointPaths(basePath, entryPoints)).toEqual([
+          ['../dist/pkg2', '../dist/pkg2'],
+          ['test', 'test'],
+        ]);
+      });
+
       function createPackage(
           basePath: AbsoluteFsPath, packageName: string, deps: string[] = []): TestFile[] {
         return [

packages/compiler-cli/ngcc/test/entry_point_finder/targeted_entry_point_finder_spec.ts

@@ -146,15 +146,18 @@ runInEachFileSystem(() => {
           paths: {
             '@x/*': ['*'],
             '@y/*/test': ['lib/*/test'],
+            '@z/*': ['../dist/moo/../*'],
           }
         };
         loadTestFiles([
           ...createPackage(
-              _Abs('/path_mapped/node_modules'), 'test', ['pkg1', '@x/pkg2', '@y/pkg3/test']),
+              _Abs('/path_mapped/node_modules'), 'test',
+              ['pkg1', '@x/pkg2', '@y/pkg3/test', '@z/pkg5']),
           ...createPackage(_Abs('/path_mapped/node_modules'), 'pkg1'),
           ...createPackage(_Abs('/path_mapped/dist'), 'pkg2', ['pkg4']),
           ...createPackage(_Abs('/path_mapped/dist/pkg2/node_modules'), 'pkg4'),
           ...createPackage(_Abs('/path_mapped/dist/lib/pkg3'), 'test'),
+          ...createPackage(_Abs('/path_mapped/dist'), 'pkg5'),
         ]);
         resolver = new DependencyResolver(
             fs, logger, {esm2015: new EsmDependencyHost(fs, new ModuleResolver(fs, pathMappings))});
@@ -166,6 +169,31 @@ runInEachFileSystem(() => {
           ['../dist/pkg2/node_modules/pkg4', '../dist/pkg2/node_modules/pkg4'],
           ['../dist/pkg2', '../dist/pkg2'],
           ['../dist/lib/pkg3/test', '../dist/lib/pkg3/test'],
+          ['../dist/pkg5', '../dist/pkg5'],
+          ['test', 'test'],
+        ]);
+      });
+
+      it('should handle pathMappings that map to files or non-existent directories', () => {
+        const basePath = _Abs('/path_mapped/node_modules');
+        const targetPath = _Abs('/path_mapped/node_modules/test');
+        const pathMappings: PathMappings = {
+          baseUrl: '/path_mapped/dist',
+          paths: {
+            '@test': ['pkg2/fesm2015/pkg2.js'],
+            '@missing': ['pkg3'],
+          }
+        };
+        loadTestFiles([
+          ...createPackage(_Abs('/path_mapped/node_modules'), 'test', []),
+          ...createPackage(_Abs('/path_mapped/dist'), 'pkg2'),
+        ]);
+        resolver = new DependencyResolver(
+            fs, logger, {esm2015: new EsmDependencyHost(fs, new ModuleResolver(fs, pathMappings))});
+        const finder = new TargetedEntryPointFinder(
+            fs, config, logger, resolver, basePath, targetPath, pathMappings);
+        const {entryPoints} = finder.findEntryPoints();
+        expect(dumpEntryPointPaths(basePath, entryPoints)).toEqual([
           ['test', 'test'],
         ]);
       });