Emit side-effect imports for global dts from Clutz externs

Clutz is soon going to emit type declarations for externs in the global namespace. To make type annotations using externs work in transitive dependencies, tsickle needs to emit side effect imports in .d.ts files. This follows what tsickle is already doing for symbols from goog modules.

PiperOrigin-RevId: 483933310

Author: frigus02

src/clutz.ts

@@ -16,8 +16,10 @@
  */
 
 import * as ts from 'typescript';
+
 import * as googmodule from './googmodule';
 import * as path from './path';
+import {isDeclaredInClutzDts} from './type_translator';
 
 /**
  * Constructs a ts.CustomTransformerFactory that postprocesses the .d.ts
@@ -317,25 +319,24 @@ function ambientModuleSymbolFromClutz(
  * because sometimes TS generates AST nodes that don't have a parent.
  */
 function clutzSymbolFromQualifiedName(
-    typeChecker: ts.TypeChecker, qname: ts.QualifiedName): ts.Symbol|undefined {
-  // Verify that the innermost reference is the look of disapproval.
-  let inner = qname;
-  while (ts.isQualifiedName(inner.left)) {
-    inner = inner.left;
-  }
-  if (inner.left.text !== 'ಠ_ಠ' || inner.right.text !== 'clutz') {
-    return undefined;  // Not a look of disapproval.
-  }
-
-  const node = qname.right;
+    typeChecker: ts.TypeChecker, name: ts.EntityName): ts.Symbol|undefined {
+  const node = ts.isQualifiedName(name) ? name.right : name;
   let sym = typeChecker.getSymbolAtLocation(node);
   if (!sym) {
     // When the declarations transformer has synthesized a reference, for
     // example due to inference, the type checker will not return a symbol
     // underlying the node.  Instead we reach through the TS internals for this.
+    // Note: Even though TypeScript declares node.symbol as always defined,
+    // we've seen instances of it being undefined.
     // tslint:disable-next-line:no-any circumventing private API
-    sym = (node as any)['symbol'] as ts.Symbol;
+    sym = (node as any)['symbol'] as ts.Symbol | undefined;
   }
+
+  if (!sym || !sym.declarations || sym.declarations.length === 0 ||
+      !isDeclaredInClutzDts(sym.declarations[0])) {
+    return undefined;
+  }
+
   return sym;
 }
 
@@ -345,11 +346,11 @@ function clutzSymbolFromQualifiedName(
  */
 function clutzSymbolFromNode(
     typeChecker: ts.TypeChecker, node: ts.Node): ts.Symbol|undefined {
-  if (ts.isTypeReferenceNode(node) && ts.isQualifiedName(node.typeName)) {
+  if (ts.isTypeReferenceNode(node)) {
     // Reference in type position.
     return clutzSymbolFromQualifiedName(typeChecker, node.typeName);
   }
-  if (ts.isTypeQueryNode(node) && ts.isQualifiedName(node.exprName)) {
+  if (ts.isTypeQueryNode(node)) {
     // Reference in typeof position.
     return clutzSymbolFromQualifiedName(typeChecker, node.exprName);
   }
@@ -403,9 +404,8 @@ function gatherNecessaryClutzImports(typeChecker: ts.TypeChecker, sf: ts.SourceF
 
 
   /**
-   * Recursively searches a node for references to members of the `ಠ_ಠ.clutz`
-   * namespace, and adds any referenced source files to the `imports` set.
-   * TODO(b/162295026): forbid this pattern and delete this logic.
+   * Recursively searches a node for references to symbols declared in Clutz
+   * .d.ts files and adds any referenced source files to the `imports` set.
    */
   function visit(node: ts.Node) {
     const sym = clutzSymbolFromNode(typeChecker, node);

src/type_translator.ts

@@ -45,9 +45,13 @@ export function isDeclaredInBuiltinLibDTS(node: ts.Node|null|
  * Returns true if the given node's source file is generated by Clutz, i.e. has
  * the magic Clutz header.
  */
-function isDeclaredInClutzDts(node: ts.Node|null|undefined): boolean {
+export function isDeclaredInClutzDts(node: ts.Node|null|undefined): boolean {
   const sourceFile = node?.getSourceFile();
-  return !!sourceFile && sourceFile.text.startsWith('//!! generated by clutz.');
+  if (!sourceFile) return false;
+  const clutz1Header = '//!! generated by clutz.';
+  const clutz2Header = '// Generated by google3/javascript/typescript/clutz2';
+  return sourceFile.text.startsWith(clutz1Header) ||
+      sourceFile.text.startsWith(clutz2Header);
 }
 
 /**

test_files/clutz_imports.declaration.no_externs/clutz2_output_demo8.d.ts

@@ -0,0 +1,18 @@
+// Generated by google3/javascript/typescript/clutz2
+/**
+ * @fileoverview This file contains the Clutz2 output for a simple goog.provide.
+ * It was manually created and is a support file for the actual test.
+ */
+
+declare namespace ಠ_ಠ.clutz {
+	namespace demo8 {
+		export class C {
+			private noStructuralTyping_demo8$C: any;
+		}
+	}  // namespace demo8
+}  // ಠ_ಠ.clutz
+
+declare module 'goog:demo8' {
+	import demo8 = ಠ_ಠ.clutz.demo8;
+	export default demo8;
+}

test_files/clutz_imports.declaration.no_externs/clutz_output_demo1.d.ts

@@ -1,3 +1,4 @@
+//!! generated by clutz.
 /**
  * @fileoverview This file contains the Clutz output for a simple goog.module.
  * It was manually created and is a support file for the actual test.

test_files/clutz_imports.declaration.no_externs/clutz_output_demo2.d.ts

@@ -1,3 +1,4 @@
+//!! generated by clutz.
 /**
  * @fileoverview This file contains the Clutz output for a simple goog.provide.
  * It was manually created and is a support file for the actual test.

test_files/clutz_imports.declaration.no_externs/clutz_output_demo3.d.ts

@@ -1,3 +1,4 @@
+//!! generated by clutz.
 /**
  * @fileoverview This file contains the Clutz output for a simple goog.module.
  * It was manually created and is a support file for the actual test.

test_files/clutz_imports.declaration.no_externs/clutz_output_demo4.d.ts

@@ -1,3 +1,4 @@
+//!! generated by clutz.
 /**
  * @fileoverview This file contains the Clutz output for a simple goog.provide.
  * It was manually created and is a support file for the actual test.

test_files/clutz_imports.declaration.no_externs/clutz_output_demo5.d.ts

@@ -1,3 +1,4 @@
+//!! generated by clutz.
 /**
  * @fileoverview This file contains the Clutz output for a simple goog.module.
  * It was manually created and is a support file for the actual test.

test_files/clutz_imports.declaration.no_externs/clutz_output_demo6.d.ts

@@ -1,3 +1,4 @@
+//!! generated by clutz.
 /**
  * @fileoverview This file contains the Clutz output for a simple goog.module,
  * with a generic class.

test_files/clutz_imports.declaration.no_externs/clutz_output_demo7.d.ts

@@ -0,0 +1,11 @@
+//!! generated by clutz.
+/**
+ * @fileoverview This file contains the Clutz output for an externs file.
+ * It was manually created and is a support file for the actual test.
+ */
+
+declare namespace demo7 {
+  class C {
+    foo(): void;
+  }
+}