Tslint migration does not consider an extends property containing an array

[sfabriece]

🚀 Feature request

Command (mark with an x)

• new
• build
• serve
• test
• e2e
• generate
• add
• update
• lint
• xi18n
• run
• config
• help
• version
• doc

Description

Running ng update @angular/cli --migrate-only tslint-version-6

with a tslint config like this:

{
  "extends": [
    "tslint:recommended",
    "tslint-plugin-prettier",
    "tslint-config-prettier"
  ],
....

fails with

 tslint configuration does not extend "tslint:recommended".
    Migration will terminate as some rules might conflict.

The following file implements the migration.
https://github.com/angular/angular-cli/blob/master/packages/schematics/angular/migrations/update-10/update-tslint.ts

Describe the solution you'd like

If you have a solution in mind, please describe it.

Describe alternatives you've considered

Have you considered any alternative solutions or workarounds?

[alan-agius4]

Hi, thanks for the issues. Actually the problem here is the error message, as the migration will be executed when extending only tslint:recommended

[sfabriece]

Can I contribute the fix to this @alan-agius4 ?

[alan-agius4]

@sfabriece, there is already a PR for this: #17323

Thanks anyways 🙂

[francovp]

For me, I did't have the "extends" array on my tslint.json and got the warning message, but the migration still completes

Using package manager: 'npm'
Collecting installed dependencies...
Found 67 dependencies.
** Executing 'tslint-version-6' of package '@angular/cli' **

> Update tslint to version 6.
    tslint configuration does not extend "tslint:recommended".
    Migration will terminate as some rules might conflict.
UPDATE package.json (3375 bytes)
UPDATE tslint.json (3099 bytes)
  Migration completed.