fix(migrations): account for variables in imports initializer (#55081)

crisbeto · dylhunn · commit 2f9d94bc4ab5 · 2024-03-28T09:40:33.000-07:00
Fixes that the control flow migration was throwing an error if the `imports` of a component are initialized to an identifier. Fixes #55080. PR Close #55081
diff --git a/packages/core/schematics/ng-generate/control-flow-migration/util.ts b/packages/core/schematics/ng-generate/control-flow-migration/util.ts
@@ -84,9 +84,16 @@ function updateImportClause(clause: ts.ImportClause, removeCommonModule: boolean
 function updateClassImports(
     propAssignment: ts.PropertyAssignment, removeCommonModule: boolean): string|null {
   const printer = ts.createPrinter();
-  const importList = propAssignment.initializer as ts.ArrayLiteralExpression;
+  const importList = propAssignment.initializer;
+
+  // Can't change non-array literals.
+  if (!ts.isArrayLiteralExpression(importList)) {
+    return null;
+  }
+
   const removals = removeCommonModule ? importWithCommonRemovals : importRemovals;
-  const elements = importList.elements.filter(el => !removals.includes(el.getText()));
+  const elements =
+      importList.elements.filter(el => !ts.isIdentifier(el) || !removals.includes(el.text));
   if (elements.length === importList.elements.length) {
     // nothing changed
     return null;
diff --git a/packages/core/schematics/test/control_flow_migration_spec.ts b/packages/core/schematics/test/control_flow_migration_spec.ts
@@ -5442,6 +5442,71 @@ describe('control flow migration', () => {
 
       expect(actual).toBe(expected);
     });
+
+    it('should not modify `imports` initialized to a variable reference', async () => {
+      writeFile('/comp.ts', [
+        `import {Component} from '@angular/core';`,
+        `import {CommonModule} from '@angular/common';\n`,
+        `const IMPORTS = [CommonModule];\n`,
+        `@Component({`,
+        `  imports: IMPORTS,`,
+        `  template: '<span *ngIf="show">Content here</span>',`,
+        `})`,
+        `class Comp {`,
+        `  show = false;`,
+        `}`,
+      ].join('\n'));
+
+      await runMigration();
+      const actual = tree.readContent('/comp.ts');
+      const expected = [
+        `import {Component} from '@angular/core';`,
+        `import {CommonModule} from '@angular/common';\n`,
+        `const IMPORTS = [CommonModule];\n`,
+        `@Component({`,
+        `  imports: IMPORTS,`,
+        `  template: '@if (show) {<span>Content here</span>}',`,
+        `})`,
+        `class Comp {`,
+        `  show = false;`,
+        `}`,
+      ].join('\n');
+
+      expect(actual).toBe(expected);
+    });
+
+    it('should handle spread elements in the `imports` array', async () => {
+      writeFile('/comp.ts', [
+        `import {Component} from '@angular/core';`,
+        `import {CommonModule} from '@angular/common';\n`,
+        `const BEFORE = [];\n`,
+        `const AFTER = [];\n`,
+        `@Component({`,
+        `  imports: [...BEFORE, CommonModule, ...AFTER],`,
+        `  template: '<span *ngIf="show">Content here</span>',`,
+        `})`,
+        `class Comp {`,
+        `  show = false;`,
+        `}`,
+      ].join('\n'));
+
+      await runMigration();
+      const actual = tree.readContent('/comp.ts');
+      const expected = [
+        `import {Component} from '@angular/core';\n\n`,
+        `const BEFORE = [];\n`,
+        `const AFTER = [];\n`,
+        `@Component({`,
+        `  imports: [...BEFORE, ...AFTER],`,
+        `  template: '@if (show) {<span>Content here</span>}',`,
+        `})`,
+        `class Comp {`,
+        `  show = false;`,
+        `}`,
+      ].join('\n');
+
+      expect(actual).toBe(expected);
+    });
   });
 
   describe('no migration needed', () => {
