@Self() decorated dependency throws an error

Type of Issue

[X] Bug Report
[ ] Feature Request

Description

With the new ng-packagr@3.0.0-rc.5 when building my package I noticed an error:

BUILD ERROR
: No provider for NgControl ("[ERROR ->]<custom-form-field></custom-form-field>")

The line it originated from came from the constructor of a custom form component using a ControlValueAccessor, it seems that @Self() decorator made the DI fail. If I remove the build passed again.

When using the @Self() decorator, the only place allowed to find the injector is the component itself.

The same issue doesn’t appear for other DI-decorators like @Host() and @Optional

How To Reproduce

Setup a minimal custom form field component using the @Self() decorator.

import { Component, Self } from '@angular/core';
import { ControlValueAccessor, NgControl } from '@angular/forms';

@Component({
  selector: 'custom-form-field',
  template: ''
})
export class CustomFormFieldComponent implements ControlValueAccessor {
  constructor(
    @Self() public controlDir: NgControl
  ) {
    controlDir.valueAccessor = this;
  }

  onChange: (val: any) => void;
  onTouched: () => void;

  writeValue(val: any) {

  }

  registerOnChange(fn: (val: any) => void) {
    this.onChange = (val) => fn(val);
  }

  registerOnTouched(fn: any) {
    this.onTouched = fn;
  }
}

When building this package where this file is included it will result into:

BUILD ERROR
: No provider for NgControl ("[ERROR ->]<custom-form-field></custom-form-field>")

Expected Behaviour

I assume it would be able to build this just fine, as the module where the component is used is using the ReactiveFormsModule which provides this NgControl. Not sure if ng-packagr has special rules in place for injecting dependencies with @Self().

Version Information

ng-packagr:            3.0.0-rc.5
@angular/compiler:     6.0.2
rollup:                0.58.2
tsickle:               0.27.5
typescript:            2.7.2

[alan-agius4]

This doesn’t seem to be a bug, ngControl can be optional and thus apart from ‘self’ one should add ‘optional’ as well, as ngControl doesn’t get inject like a normal service for instance like httpClient, it gets injected based on the usage of the component.

Check an example; https://github.com/angular/material2/blob/master/src/lib/input/input.ts

Also ng-packagr doesn’t have any logic for this, its alll done by the Angular Compiler.

[abbazabacto]

Thanks for the amazing quick reply @alan-agius4

Adding @Optional() seems to make the compiler happy:

constructor(
    @Optional() @Self() public controlDir: NgControl,