2.0.0 Breaking Changes

[bradzacher]

I wanted somewhere to keep track of the breaking changes we should make as part of a 2.0.0 release.

Deprecated Rules:

• (pr feat(eslint-plugin)!: remove deprecated rules #739) remove deprecated rule prefer-interface (replaced by consistent-type-definitions)
• (pr feat(eslint-plugin)!: remove deprecated rules #739) remove deprecated rule no-triple-slash-reference (replaced by triple-slash-reference)
• (pr feat(eslint-plugin)!: add rule consistent-type-assertions #731) remove deprecated rule no-angle-bracket-type-assertion (replaced by consistent-type-assertions)
• (pr feat(eslint-plugin)!: add rule consistent-type-assertions #731) remove deprecated rule no-object-literal-type-assertion (replaced by consistent-type-assertions)

Misc:

• (pr feat: Support eslint@6 #645) Support eslint 6 (drop node 6 support)
• (pr fix(eslint-plugin)!: remove "isTypescriptFile". #594) kill isTypescriptFile checks Make typescript-eslint rules compatible with .vue files #524
• (pr feat(eslint-plugin)!: add rule consistent-type-assertions #731) generalize no-angle-bracket-type-assertion (Rule suggestion: generalize @typescript-eslint/no-angle-bracket-type-assertion #332) and merge in no-object-literal-type-assertion
• (pr feat(typescript-estree)!: throw error on file not in project when project set #760) protection against most common performance pitfall
• (pr fix(eslint-plugin): [explicit-function-return-type] Fix allowExpressions ignoring default exports #831) explicit-function-return-type allowExpressions shouldn't ignore export default () => {}
• rename @typescript-eslint/experimental-utils to @typescript-eslint/utils (feat: Move shared types into their own package #425 (review)) will do in v3
• look into renaming a number of rules Suggestion: standardize against prefixing rule names with "no-" #203 will do with a later major bump..

Recommended stuff:

• reevaluate rule defaults
  • (pr feat(eslint-plugin)!: change recommended config #729) make explicit-function-return-type more relaxed by default, as it's the standard usage ([explicit-function-return-type] Consider allowExpressions=true and allowTypedFunctionExpressions=true as default #493)
  • (feat(eslint-plugin)!: [promise-function-async] make allowAny default true #733) Remove the allowAny option from the promise-function-async rule and make it the default (from comment below)
• (pr feat(eslint-plugin)!: change recommended config #729) update the recommended rule set with new rules (and remove some rules) [recommended] Remove stylistic rules from recommended #651
• (pr feat(eslint-plugin)!: recommended-requiring-type-checking config #846) split the recommended into a base set not requiring type info, and an extension set requiring type info, so people can have a fast experience by default.

[bradzacher]

Potential other changes that need discussions:

• Maybe merge no-unnecessary-type-assertion and no-inferrable-types
• feat(eslint-plugin)!: Move opinionated rules from 'eslint-recommended' to 'recommended' #595 (maybe? Is this too opinionated?)

[IlCallo]

I'm sorry to be that type of dev but... Do you have a ETA/roadmap for v2.0.0?

We are working to move Quasar TS extension from TSLint to ESLint using this package, but some things you'll resolve in v2 are things we'll need asap.
So we are trying to understand if waiting for v2 is an option or we shall fork the repo and apply the fixes we care the most right away, keeping it updated with upstream

[bradzacher]

@IlCallo - what PRs are you waiting for specifically?

Having a quick look at the linked issue..

• isTypescriptFile only affects two rules, so that shouldn't stop you (Make typescript-eslint rules compatible with .vue files #524)
• FYI Vue files have somewhat nebulous support right now because of weird interactions with how vue-eslint-parser interacts with perf optimisations we added (Parsing errors when combined with eslint-plugin-vue as of 1.5.0 #404).
  • I'd love someone who's familiar with vue to dig in more into the problem - as I have never used it before and have no idea how vue works. There are some ideas listed in Parsing errors when combined with eslint-plugin-vue as of 1.5.0 #404.

[IlCallo]

#524 is the main problem we have, because if doesn't allow people working on SFC to access your linting capabilities, forcing to separate the typescript part into a second file.

It's not "blocking" in any way, we'll probably migrate to typescript-eslint anyway, but we'd like to have that problem solved by day-0 when we release the update, that's why we were thinking about forking the repo :)
Plus some other problems we can try to fix in our fork and then send upstream.

I was asking a roadmap/ETA to better coordinate the efforts

[bradzacher]

isTypescriptFile only blocks two rules - explicit-member-accessibility and explicit-function-return-type. The rest of the repo doesn't use the utility function. It's been in those rules for ages back before eslint overrides were widely used.

The optimistic plan is to look into handling all of the breaking changes within the next week or two. But as we're all volunteer maintaners, life could get in the way of that..

Note #404 will hard block you guys though. You cannot migrate to >=1.5.0, because 1.5.0 was the version that essentially broke vue SFC support.

[IlCallo]

Ok, I'll take a closer look to #404 and see if I can help to resolve that

[JamesHenry]

FYI for any subscribers to this issue, we have begun merging breaking change PRs and the canary releases (i.e. master) are now on 2.x.x.

We will likely promote v2.x.x to stable in one week. We won't leave such a big gap until v3.x.x but we also want to be mindful of churn, so if you do have breaking changes you want to see now is the time to champion/implement them :)

Please also do us a favour and install from @canary and report any issues.

Thanks!

[corbinu]

Installed canary been using it for a 2 days and seems fine

[JamesHenry]

Thanks @corbinu - I have just published a new canary manually: 2.0.0-alpha.3

[JamesHenry]

Unfortunately we haven't quite been able to get everything wrapped up within the week. We will let the updated v2 alphas bed in for one more week and then publish v2 to latest next weekend.

Please help us by testing out the latest alphas on your codebases!

• 2.0.0-alpha.4 has been published and contains the new protection against performance issues which occur when files are being linted which fall outside your TypeScript Programs (feat(typescript-estree)!: throw error on file not in project when project set #760)

- 2.0.0-alpha.5 has not yet been published but will contain the updates to the recommended config. We will publish this as soon as it's ready.
UPDATE: see next comment

[trivikr]

Thanks @JamesHenry for follow-up.
Is there any update on v2 release this week?

[JamesHenry]

I'm not very well at the moment, so we are pushing the release back a few more days. I have just published 2.0.0-alpha.5 which contains all the commits to master since the last canary, so nobody should be blocked in any way

[trivikr]

Take care @JamesHenry!
Health always comes first 😊

[bradzacher]

v2.0.0 is released! 🎉