signal-input-migration on transform without explicit typing #63541
Description
Which @angular/* package(s) are the source of the bug?
core
Is this a regression?
No
Description
When I run the signal-input-migration on an app containing an @input() using a transform function without explicit typing, for example:
@Input({transform: value1 => value1 * 10})
public value: number = 0;The migration does throws errors in safe migration mode:
➜ src git:(main) npx @angular/cli@20 generate @angular/core:signal-input-migration
✔ Which directory do you want to migrate? ./
✔ Do you want to migrate as much as possible, even if it may break your build? No
Preparing analysis for: tsconfig.app.json...
Scanning for inputs: tsconfig.app.json...
/src/app/my-component/my-component.ts: Error: FatalDiagnosticError: Code: 1010, Message: Input transform function first parameter must have a type
Value could not be determined statically.
Preparing analysis for: tsconfig.spec.json...
Scanning for inputs: tsconfig.spec.json...
/src/app/my-component/my-component.ts: Error: FatalDiagnosticError: Code: 1010, Message: Input transform function first parameter must have a type
Value could not be determined statically.
Processing analysis data between targets...
Running migration for: tsconfig.app.json...
/src/app/my-component/my-component.ts: Error: FatalDiagnosticError: Code: 1010, Message: Input transform function first parameter must have a type
Value could not be determined statically.
Running migration for: tsconfig.spec.json...
/src/app/my-component/my-component.ts: Error: FatalDiagnosticError: Code: 1010, Message: Input transform function first parameter must have a type
Value could not be determined statically.
Successfully migrated to signal inputs 🎉
-> Migrated 1/1 inputs.
UPDATE src/app/my-component/my-component.ts (276 bytes)but still migrates the given input, erasing its transform function:
import {Component, input} from '@angular/core';
@Component({
selector: 'app-my-component',
imports: [],
templateUrl: './my-component.html',
standalone: true,
styleUrl: './my-component.css'
})
export class MyComponent {
public readonly value = input<number>(0);
}Since the app's behaviour is changed doing so, I would expect the migration to not do anything on this @Input and, using the option --insert-todos, indicate what the action to fix the issue would be (add explicit typing on the transform function)
Please provide a link to a minimal reproduction of the bug
https://github.com/Lysoun/angular-signal-input-migration-transform-issue
Please provide the exception or error you saw
Error: FatalDiagnosticError: Code: 1010, Message: Input transform function first parameter must have a type
Please provide the environment you discovered this bug in (run ng version)
Angular CLI: 20.2.1
Node: 22.16.0
Package Manager: npm 10.9.2
OS: darwin arm64
Angular: 20.2.3
... common, compiler, compiler-cli, core, forms
... platform-browser, router
Package Version
------------------------------------
@angular-devkit/architect 0.2002.1
@angular-devkit/core 20.2.1
@angular-devkit/schematics 20.2.1
@angular/build 20.2.1
@angular/cli 20.2.1
@schematics/angular 20.2.1
rxjs 7.8.2
typescript 5.9.2
zone.js 0.15.1
Anything else?
No response