fix(compiler): do not recurse to find static symbols of same module

To create the symbols of a module, the static symbol resolver first gets
all the symbols loaded in the module by an export statement. For `export
* from './module'`-like statements, all symbols from `./module` must be
loaded. In cases where the exporting module is actually the same module
that the export statement is in, this causes an unbounded recursive
resolution of the same module.

Exports of the same module are not needed, as their symbols will be
resolved when the symbols in the module metadata's `metadata` key is
explored.

This commit resolves the unbounded recursion by loading exporting
modules only if they differ from the module currently being resolved.

Closes angular/vscode-ng-language-service#593

Author: Ayaz Hafiz

packages/compiler/src/aot/static_symbol_resolver.ts

@@ -313,9 +313,9 @@ export class StaticSymbolResolver {
             }
           });
         } else {
-          // handle the symbols via export * directives.
+          // Handle the symbols loaded by 'export *' directives.
           const resolvedModule = this.resolveModule(moduleExport.from, filePath);
-          if (resolvedModule) {
+          if (resolvedModule && resolvedModule !== filePath) {
             const nestedExports = this.getSymbolsOf(resolvedModule);
             nestedExports.forEach((targetSymbol) => {
               const sourceSymbol = this.getStaticSymbol(filePath, targetSymbol.name);

packages/compiler/test/aot/static_symbol_resolver_spec.ts

@@ -15,7 +15,6 @@ import * as ts from 'typescript';
 const TS_EXT = /(^.|(?!\.d)..)\.ts$/;
 
 describe('StaticSymbolResolver', () => {
-  const noContext = new StaticSymbol('', '', []);
   let host: StaticSymbolResolverHost;
   let symbolResolver: StaticSymbolResolver;
   let symbolCache: StaticSymbolCache;
@@ -103,6 +102,19 @@ describe('StaticSymbolResolver', () => {
         .toBe(symbolResolver.getStaticSymbol('/tmp/src/export.ts', 'exportedObj', ['someMember']));
   });
 
+  it('should not explore re-exports of the same module', () => {
+    init({
+      '/tmp/src/test.ts': `
+        export * from './test';
+
+        export const testValue = 10;
+      `,
+    });
+
+    const symbols = symbolResolver.getSymbolsOf('/tmp/src/test.ts');
+    expect(symbols).toEqual([symbolResolver.getStaticSymbol('/tmp/src/test.ts', 'testValue')]);
+  });
+
   it('should use summaries in resolveSymbol and prefer them over regular metadata', () => {
     const symbolA = symbolCache.get('/test.ts', 'a');
     const symbolB = symbolCache.get('/test.ts', 'b');
@@ -140,7 +152,6 @@ describe('StaticSymbolResolver', () => {
 
   it('should read the exported symbols of a file from the summary and ignore exports in the source',
      () => {
-       const someSymbol = symbolCache.get('/test.ts', 'a');
        init(
            {'/test.ts': 'export var b = 2'},
            [{symbol: symbolCache.get('/test.ts', 'a'), metadata: 1}]);