ng update error message: Cannot find module 'tslint'.

[wartab]

🐞 Bug report

Command (mark with an x)

- [ ] new
- [ ] build
- [ ] serve
- [ ] test
- [ ] e2e
- [ ] generate
- [ ] add
- [x] update
- [ ] lint
- [ ] xi18n
- [ ] run
- [ ] config
- [ ] help
- [ ] version
- [ ] doc

Is this a regression?

Description

It seems like some part of angular-cli uses tslint to perform some migration step from Angular 7 to Angular 8.
When running npm update @angular/cli @angular/core @angular/material, the procedure crashes after static query migration is performed.
After installing tslint, it does not crash anymore, but our environment does not make use of tslint and it doesn't seem to be a dependency of angular-cli either.

🔬 Minimal Reproduction

• Have an Angular 7 project without tslint
• Run ng update @angular/cli @angular/core @angular/material

🔥 Exception or Error

Cannot find module 'tslint'

🌍 Your Environment

     _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/


Angular CLI: 7.3.9
Node: 10.14.2
OS: win32 x64
Angular: 7.2.15
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.13.9
@angular-devkit/build-angular     0.13.9
@angular-devkit/build-optimizer   0.13.9
@angular-devkit/build-webpack     0.13.9
@angular-devkit/core              7.3.9
@angular-devkit/schematics        7.3.9
@angular/cdk                      7.3.7
@angular/cli                      7.3.9
@angular/material                 7.3.7
@ngtools/webpack                  7.3.9
@schematics/angular               7.3.9
@schematics/update                0.13.9
rxjs                              6.5.2
typescript                        3.2.4
webpack                           4.29.0

Anything else relevant?

[devversion]

Problem here is that the @angular-devkit/schematics package uses tslint to provide the TslintFix schematic task. Ideally it would specify tslint as a dependency as it is directly used.

angular-cli/packages/angular_devkit/schematics/tasks/tslint-fix/executor.ts

Lines 13 to 15 in 3afdab2

	Configuration as ConfigurationNS,
	Linter as LinterNS,
	} from 'tslint'; // tslint:disable-line:no-implicit-dependencies

Migrations such as these from @angular/material can depend on these to apply fixes.

[alan-agius4]

The problem is

angular-cli/packages/angular_devkit/schematics/tasks/tslint-fix/executor.ts

Line 96 in 3afdab2

const tslint = require(resolve('tslint', {

😛

As the above mentioned part only imports for types

[devversion]

ups right 😄 In any way, the TslintFix task has a dependency on tslint.