fix(ngcc): ensure that bundle `rootDir` is the package path (#34212)

Previously the `rootDir` was set to the entry-point path but
this is incorrect if the source files are stored in a directory outside
the entry-point path. This is the case in the latest versions of the
Angular CDK.

Instead the `rootDir` should be the containing package path, which is
guaranteed to include all the source for the entry-point.

---

A symptom of this is an error when ngcc is trying to process the source of
an entry-point format after the entry-point's typings have already been
processed by a previous processing run.

During processing the `_toR3Reference()` function gets called which in turn
makes a call to `ReflectionHost.getDtsDeclaration()`. If the typings files
are also being processed this returns the node from the dts typings files.

But if we have already processed the typings files and are now processing
only an entry-point format without typings, the call to
`ReflectionHost.getDtsDeclaration()` returns `null`.

When this value is `null`, a JS `valueRef` is passed through as the DTS
`typeRef` to the `ReferenceEmitter`. In this case, the `ReferenceEmitter`
fails during `emit()` because no `ReferenceEmitStrategy` is able to provide
an emission:

1) The `LocalIdentifierStrategy` is not able help because in this case
`ImportMode` is `ForceNewImport`.
2) The `LogicalProjectStrategy` cannot find the JS file below the `rootDir`.

The second strategy failure is fixed by this PR.

Fixes https://github.com/angular/ngcc-validation/issues/495

PR Close #34212

packages/compiler-cli/ngcc/src/packages/entry_point_bundle.ts

@@ -47,15 +47,14 @@ export function makeEntryPointBundle(
     mirrorDtsFromSrc: boolean = false,
     enableI18nLegacyMessageIdFormat: boolean = true): EntryPointBundle {
   // Create the TS program and necessary helpers.
+  const rootDir = entryPoint.package;
   const options: ts.CompilerOptions = {
     allowJs: true,
     maxNodeModuleJsDepth: Infinity,
-    noLib: true,
+    noLib: true, rootDir, ...pathMappings
-    rootDir: entryPoint.path, ...pathMappings
   };
   const srcHost = new NgccSourcesCompilerHost(fs, options, entryPoint.path);
   const dtsHost = new NgtscCompilerHost(fs, options);
-  const rootDirs = [absoluteFrom(entryPoint.path)];
 
   // Create the bundle programs, as necessary.
   const absFormatPath = fs.resolve(entryPoint.path, formatPath);
@@ -71,8 +70,11 @@ export function makeEntryPointBundle(
                              null;
   const isFlatCore = isCore && src.r3SymbolsFile === null;
 
-  return {entryPoint, format, rootDirs, isCore,
+  return {
-          isFlatCore, src,    dts,      enableI18nLegacyMessageIdFormat};
+    entryPoint,
+    format,
+    rootDirs: [rootDir], isCore, isFlatCore, src, dts, enableI18nLegacyMessageIdFormat
+  };
 }
 
 function computePotentialDtsFilesFromJsFiles(

packages/compiler-cli/ngcc/test/packages/entry_point_bundle_spec.ts

@@ -148,6 +148,16 @@ runInEachFileSystem(() => {
           name: _('/node_modules/internal/esm2015/src/internal.js'),
           contents: 'export function internal();'
         },
+
+        // A package with a secondary entry-point that has source files in a different tree
+        {
+          name: _('/node_modules/primary/secondary/index.d.ts'),
+          contents: 'export declare function secondary();'
+        },
+        {
+          name: _('/node_modules/primary/esm2015/secondary/index.js'),
+          contents: 'export function secondary();'
+        },
       ]);
     }
 
@@ -268,5 +278,24 @@ runInEachFileSystem(() => {
          expect(esm5bundle.dts !.program.getSourceFiles().map(sf => sf.fileName))
              .not.toContain(absoluteFrom('/node_modules/test/internal.d.ts'));
        });
+
+    it('should set the `rootDir` to the package path not the entry-point path', () => {
+      setupMockFileSystem();
+      const fs = getFileSystem();
+      const entryPoint: EntryPoint = {
+        name: 'secondary',
+        packageJson: {name: 'secondary'},
+        package: absoluteFrom('/node_modules/primary'),
+        path: absoluteFrom('/node_modules/primary/secondary'),
+        typings: absoluteFrom('/node_modules/primary/secondary/index.d.ts'),
+        compiledByAngular: true,
+        ignoreMissingDependencies: false,
+        generateDeepReexports: false,
+      };
+      const bundle = makeEntryPointBundle(
+          fs, entryPoint, './index.js', false, 'esm2015', /* transformDts */ true,
+          /* pathMappings */ undefined, /* mirrorDtsFromSrc */ true);
+      expect(bundle.rootDirs).toEqual([absoluteFrom('/node_modules/primary')]);
+    });
   });
 });