fix(core): missing-injectable migration should handle forwardRef (#33286)

Currently the migration is unable to migrate instances where
the provider definition uses `forwardRef`. Since this is a
common pattern, we should support that from within the migration.

The solution to the problem is adding a foreign function resolver
to the `PartialEvaluator`. This basically matches the usage of
the static evaluation that is used by the ngtsc annotations.

PR Close #33286

packages/core/schematics/migrations/missing-injectable/BUILD.bazel

@@ -11,6 +11,7 @@ ts_library(
         "//packages/core/schematics/test:__pkg__",
     ],
     deps = [
+        "//packages/compiler-cli/src/ngtsc/annotations",
         "//packages/compiler-cli/src/ngtsc/imports",
         "//packages/compiler-cli/src/ngtsc/partial_evaluator",
         "//packages/compiler-cli/src/ngtsc/reflection",

packages/core/schematics/migrations/missing-injectable/transform.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {forwardRefResolver} from '@angular/compiler-cli/src/ngtsc/annotations/src/util';
 import {Reference} from '@angular/compiler-cli/src/ngtsc/imports';
 import {DynamicValue, PartialEvaluator, ResolvedValue} from '@angular/compiler-cli/src/ngtsc/partial_evaluator';
 import {TypeScriptReflectionHost} from '@angular/compiler-cli/src/ngtsc/reflection';
@@ -67,7 +68,7 @@ export class MissingInjectableTransform {
       return [];
     }
 
-    const evaluatedExpr = this.partialEvaluator.evaluate(module.providersExpr);
+    const evaluatedExpr = this._evaluateExpression(module.providersExpr);
 
     if (!Array.isArray(evaluatedExpr)) {
       return [{
@@ -89,7 +90,7 @@ export class MissingInjectableTransform {
 
     // Migrate "providers" on directives and components if defined.
     if (directive.providersExpr) {
-      const evaluatedExpr = this.partialEvaluator.evaluate(directive.providersExpr);
+      const evaluatedExpr = this._evaluateExpression(directive.providersExpr);
       if (!Array.isArray(evaluatedExpr)) {
         return [
           {node: directive.providersExpr, message: `Providers are not statically analyzable.`}
@@ -100,7 +101,7 @@ export class MissingInjectableTransform {
 
     // Migrate "viewProviders" on components if defined.
     if (directive.viewProvidersExpr) {
-      const evaluatedExpr = this.partialEvaluator.evaluate(directive.viewProvidersExpr);
+      const evaluatedExpr = this._evaluateExpression(directive.viewProvidersExpr);
       if (!Array.isArray(evaluatedExpr)) {
         return [
           {node: directive.viewProvidersExpr, message: `Providers are not statically analyzable.`}
@@ -150,6 +151,14 @@ export class MissingInjectableTransform {
     }
   }
 
+  /**
+   * Evaluates the given TypeScript expression using the partial evaluator with
+   * the foreign function resolver for handling "forwardRef" calls.
+   */
+  private _evaluateExpression(expr: ts.Expression): ResolvedValue {
+    return this.partialEvaluator.evaluate(expr, forwardRefResolver);
+  }
+
   /**
    * Visits the given resolved value of a provider. Providers can be nested in
    * arrays and we need to recursively walk through the providers to be able to

packages/core/schematics/test/missing_injectable_migration_spec.ts

@@ -48,6 +48,10 @@ describe('Missing injectable migration', () => {
     // Switch into the temporary directory path. This allows us to run
     // the schematic against our custom unit test tree.
     shx.cd(tmpDirPath);
+
+    writeFile('/node_modules/@angular/core/index.d.ts', `
+      export declare function forwardRef(fn: Function);
+    `);
   });
 
   afterEach(() => {
@@ -135,6 +139,24 @@ describe('Missing injectable migration', () => {
           .toContain(`{ ${type}, Injectable } from '@angular/core`);
     });
 
+    it(`should migrate object literal provider with forwardRef in ${type}`, async() => {
+      writeFile('/index.ts', `
+        import {${type}, forwardRef} from '@angular/core';
+                  
+        @${type}({${propName}: [{provide: forwardRef(() => MyService)}]})
+        export class TestClass {}
+
+        export class MyService {}
+      `);
+
+      await runMigration();
+
+      expect(warnOutput.length).toBe(0);
+      expect(tree.readContent('/index.ts')).toMatch(/@Injectable\(\)\s+export class MyService/);
+      expect(tree.readContent('/index.ts'))
+          .toContain(`{ ${type}, forwardRef, Injectable } from '@angular/core`);
+    });
+
     it(`should not migrate object literal provider with "useValue" in ${type}`, async() => {
       writeFile('/index.ts', `
         import {${type}} from '@angular/core';