fix(core): preserve comments in internal inject migration (angular#60588)

The internal-only combineMemberInitializers option
for the inject migration sometimes dropped the
doc comments from the members.

PR Close angular#60588

Author: Ryan Russell

packages/core/schematics/ng-generate/inject-migration/migration.ts

@@ -773,24 +773,36 @@ function applyInternalOnlyChanges(
 
   result.toCombine.forEach(({declaration, initializer}) => {
     const initializerStatement = closestNode(initializer, ts.isStatement);
-    const newProperty = ts.factory.createPropertyDeclaration(
-      cloneModifiers(declaration.modifiers),
-      cloneName(declaration.name),
-      declaration.questionToken,
-      declaration.type,
-      initializer,
-    );
 
     // If the initialization order is being preserved, we have to remove the original
     // declaration and re-declare it. Otherwise we can do the replacement in-place.
     if (preserveInitOrder) {
+      // Preserve comment in the new property since we are removing the entire node.
+      const newProperty = ts.factory.createPropertyDeclaration(
+        declaration.modifiers,
+        declaration.name,
+        declaration.questionToken,
+        declaration.type,
+        initializer,
+      );
+
       tracker.removeNode(declaration, true);
       removedMembers.add(declaration);
       afterInjectCalls.push(
         memberIndentation +
           printer.printNode(ts.EmitHint.Unspecified, newProperty, declaration.getSourceFile()),
       );
     } else {
+      // Strip comments from the declaration since we are replacing just
+      // the node, not the leading comment.
+      const newProperty = ts.factory.createPropertyDeclaration(
+        cloneModifiers(declaration.modifiers),
+        cloneName(declaration.name),
+        declaration.questionToken,
+        declaration.type,
+        initializer,
+      );
+
       tracker.replaceNode(declaration, newProperty);
     }
 

packages/core/schematics/test/inject_migration_spec.ts

@@ -2221,6 +2221,48 @@ describe('inject migration', () => {
       ]);
     });
 
+    it('should account for doc strings when inlining initializers and combining in initialization order', async () => {
+      writeFile(
+        '/dir.ts',
+        [
+          `import { Directive } from '@angular/core';`,
+          `import { Foo } from 'foo';`,
+          ``,
+          `@Directive()`,
+          `class MyDir {`,
+          `  /** Value of Foo */`,
+          `  private readonly value: number;`,
+          ``,
+          `  /** ID of Foo */`,
+          `  id: string;`,
+          ``,
+          `  constructor(private foo: Foo) {`,
+          `    this.value = this.foo.getValue();`,
+          `    this.id = this.value.toString();`,
+          `  }`,
+          `}`,
+        ].join('\n'),
+      );
+
+      await runInternalMigration();
+
+      expect(tree.readContent('/dir.ts').split('\n')).toEqual([
+        `import { Directive, inject } from '@angular/core';`,
+        `import { Foo } from 'foo';`,
+        ``,
+        `@Directive()`,
+        `class MyDir {`,
+        `  private foo = inject(Foo);`,
+        // The indentation of the members here is slightly off,
+        // but it's not a problem because this code is internal-only.
+        `  /** Value of Foo */`,
+        `private readonly value: number = this.foo.getValue();`,
+        `  /** ID of Foo */`,
+        `id: string = this.value.toString();`,
+        `}`,
+      ]);
+    });
+
     it('should hoist property declarations that were not combined above the inject() calls', async () => {
       writeFile(
         '/dir.ts',