fix(ivy): in ngcc, handle inline exports in commonjs code (#32129)

One of the compiler's tasks is to enumerate the exports of a given ES
module. This can happen for example to resolve `foo.bar` where `foo` is a
namespace import:

```typescript
import * as foo from './foo';

@NgModule({
  directives: [foo.DIRECTIVES],
})
```

In this case, the compiler must enumerate the exports of `foo.ts` in order
to evaluate the expression `foo.DIRECTIVES`.

When this operation occurs under ngcc, it must deal with the different
module formats and types of exports that occur. In commonjs code, a problem
arises when certain exports are downleveled.

```typescript
export const DIRECTIVES = [
  FooDir,
  BarDir,
];
```

can be downleveled to:

```javascript
exports.DIRECTIVES = [
  FooDir,
  BarDir,
```

Previously, ngtsc and ngcc expected that any export would have an associated
`ts.Declaration` node. `export class`, `export function`, etc. all retain
`ts.Declaration`s even when downleveled. But the `export const` construct
above does not. Therefore, ngcc would not detect `DIRECTIVES` as an export
of `foo.ts`, and the evaluation of `foo.DIRECTIVES` would therefore fail.

To solve this problem, the core concept of an exported `Declaration`
according to the `ReflectionHost` API is split into a `ConcreteDeclaration`
which has a `ts.Declaration`, and an `InlineDeclaration` which instead has
a `ts.Expression`. Differentiating between these allows ngcc to return an
`InlineDeclaration` for `DIRECTIVES` and correctly keep track of this
export.

PR Close #32129

packages/compiler-cli/ngcc/test/host/commonjs_host_spec.ts

@@ -9,7 +9,7 @@ import * as ts from 'typescript';
 
 import {absoluteFrom, getFileSystem, getSourceFileOrError} from '../../../src/ngtsc/file_system';
 import {TestFile, runInEachFileSystem} from '../../../src/ngtsc/file_system/testing';
-import {ClassMemberKind, CtorParameter, Import, isNamedClassDeclaration, isNamedFunctionDeclaration, isNamedVariableDeclaration} from '../../../src/ngtsc/reflection';
+import {ClassMemberKind, CtorParameter, Import, InlineDeclaration, isNamedClassDeclaration, isNamedFunctionDeclaration, isNamedVariableDeclaration} from '../../../src/ngtsc/reflection';
 import {getDeclaration} from '../../../src/ngtsc/testing';
 import {loadFakeCore, loadTestFiles} from '../../../test/helpers';
 import {CommonJsReflectionHost} from '../../src/host/commonjs_host';
@@ -31,6 +31,7 @@ runInEachFileSystem(() => {
     let SIMPLE_ES2015_CLASS_FILE: TestFile;
     let SIMPLE_CLASS_FILE: TestFile;
     let FOO_FUNCTION_FILE: TestFile;
+    let INLINE_EXPORT_FILE: TestFile;
     let INVALID_DECORATORS_FILE: TestFile;
     let INVALID_DECORATOR_ARGS_FILE: TestFile;
     let INVALID_PROP_DECORATORS_FILE: TestFile;
@@ -164,6 +165,18 @@ exports.foo = foo;
 `,
       };
 
+      INLINE_EXPORT_FILE = {
+        name: _('/inline_export.js'),
+        contents: `
+var core = require('@angular/core');
+function foo() {}
+foo.decorators = [
+  { type: core.Directive, args: [{ selector: '[ignored]' },] }
+];
+exports.directives = [foo];
+`,
+      };
+
       INVALID_DECORATORS_FILE = {
         name: _('/invalid_decorators.js'),
         contents: `
@@ -1629,7 +1642,7 @@ exports.ExternalModule = ExternalModule;
           const exportDeclarations = host.getExportsOfModule(file);
           expect(exportDeclarations).not.toBe(null);
           expect(Array.from(exportDeclarations !.entries())
-                     .map(entry => [entry[0], entry[1].node.getText(), entry[1].viaModule]))
+                     .map(entry => [entry[0], entry[1].node !.getText(), entry[1].viaModule]))
               .toEqual([
                 ['Directive', `Directive: FnWithArg<(clazz: any) => any>`, '@angular/core'],
                 ['a', `a = 'a'`, './a_module'],
@@ -1655,7 +1668,7 @@ exports.ExternalModule = ExternalModule;
           const exportDeclarations = host.getExportsOfModule(file);
           expect(exportDeclarations).not.toBe(null);
           expect(Array.from(exportDeclarations !.entries())
-                     .map(entry => [entry[0], entry[1].node.getText(), entry[1].viaModule]))
+                     .map(entry => [entry[0], entry[1].node !.getText(), entry[1].viaModule]))
               .toEqual([
                 ['Directive', `Directive: FnWithArg<(clazz: any) => any>`, _('/b_module')],
                 ['a', `a = 'a'`, _('/b_module')],
@@ -1673,6 +1686,19 @@ exports.ExternalModule = ExternalModule;
                 ['xtra2', `xtra2 = 'xtra2'`, _('/xtra_module')],
               ]);
         });
+
+        it('should handle inline exports', () => {
+          loadTestFiles([INLINE_EXPORT_FILE]);
+          const {program, host: compilerHost} = makeTestBundleProgram(_('/inline_export.js'));
+          const host = new CommonJsReflectionHost(new MockLogger(), false, program, compilerHost);
+          const file = getSourceFileOrError(program, _('/inline_export.js'));
+          const exportDeclarations = host.getExportsOfModule(file);
+          expect(exportDeclarations).not.toBeNull();
+          const decl = exportDeclarations !.get('directives') as InlineDeclaration;
+          expect(decl).not.toBeUndefined();
+          expect(decl.node).toBeNull();
+          expect(decl.expression).toBeDefined();
+        });
       });
 
       describe('getClassSymbol()', () => {

packages/compiler-cli/ngcc/test/host/esm2015_host_spec.ts

@@ -1538,8 +1538,9 @@ runInEachFileSystem(() => {
           'SomeClass',
         ]);
 
-        const values = Array.from(exportDeclarations !.values())
-                           .map(declaration => [declaration.node.getText(), declaration.viaModule]);
+        const values =
+            Array.from(exportDeclarations !.values())
+                .map(declaration => [declaration.node !.getText(), declaration.viaModule]);
         expect(values).toEqual([
           [`Directive: FnWithArg<(clazz: any) => any>`, null],
           [`a = 'a'`, null],

packages/compiler-cli/ngcc/test/host/esm5_host_import_helper_spec.ts

@@ -399,7 +399,7 @@ export { SomeDirective };
 
             const declaration = host.getDeclarationOfIdentifier(ngModuleRef !);
             expect(declaration).not.toBe(null);
-            expect(declaration !.node.getText()).toContain('function HttpClientXsrfModule()');
+            expect(declaration !.node !.getText()).toContain('function HttpClientXsrfModule()');
           });
         });
         describe('getVariableValue', () => {

packages/compiler-cli/ngcc/test/host/esm5_host_spec.ts

@@ -1842,8 +1842,9 @@ runInEachFileSystem(() => {
           'SomeClass',
         ]);
 
-        const values = Array.from(exportDeclarations !.values())
-                           .map(declaration => [declaration.node.getText(), declaration.viaModule]);
+        const values =
+            Array.from(exportDeclarations !.values())
+                .map(declaration => [declaration.node !.getText(), declaration.viaModule]);
         expect(values).toEqual([
           [`Directive: FnWithArg<(clazz: any) => any>`, null],
           [`a = 'a'`, null],

packages/compiler-cli/ngcc/test/host/umd_host_spec.ts

@@ -1741,7 +1741,7 @@ runInEachFileSystem(() => {
           const exportDeclarations = host.getExportsOfModule(file);
           expect(exportDeclarations).not.toBe(null);
           expect(Array.from(exportDeclarations !.entries())
-                     .map(entry => [entry[0], entry[1].node.getText(), entry[1].viaModule]))
+                     .map(entry => [entry[0], entry[1].node !.getText(), entry[1].viaModule]))
               .toEqual([
                 ['Directive', `Directive: FnWithArg<(clazz: any) => any>`, '@angular/core'],
                 ['a', `a = 'a'`, '/a_module'],