feat: upgrade to prettier 3 and prettier-plugin-svelte 3

[benmccann]

This will give users the new versions via create-svelte. The rest of the change is internal

closes #10751
closes #10716

[changeset-bot]

🦋 Changeset detected

Latest commit: 2954e8b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
create-svelte	Minor

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[dummdidumm]

This needs some additional adjustments which i wrote down here. TLDR config file adjustments, needs --plugin prettier-plugin-svelte in the package.json script.

Given all this is quite new we may want to wait a few more weeks, maybe Prettier fixes the upstream bug by then.

[benmccann]

Okay. Seems this is blocked by prettier/prettier#15079. There's a PR for it, so hopefully we don't have to wait too long: prettier/prettier#15155

[benmccann]

prettier/prettier#15433 was merged with the fix. It's not been released yet though. It looks like it will be included in prettier 3.1 (prettier/prettier#15462)

[polyzen]

Prettier 3.1 has been released with the fix 🚀

[dummdidumm]

I saw these were removed - could someone clarify why? Or why they were needed before? (probably related to the major version bump?)

[benmccann]

Prettier now ignores files in .gitignore by default. It will also search up the directory tree for a config file, so you don't need to point at the config file

[hyunbinseo]

Finally! A migration guide would be nice for existing projects.

# jsconfig.json, tsconfig.json
+ "moduleResolution": "bundler"

# package.json
- "lint": "prettier --plugin-search-dir . --check . && eslint .",
- "format": "prettier --plugin-search-dir . --write ."
+ "lint": "prettier --check . && eslint .",
+ "format": "prettier --write ."

# package.json
- "prettier": "^2.8.8",
- "prettier-plugin-svelte": "^2.10.1",
+ "prettier": "^3.1.0",
+ "prettier-plugin-svelte": "^3.1.0",

# .prettierrc
- "pluginSearchDirs": ["."],

[hyunbinseo]

Can't eslint-config-prettier be bumped to v9? It does not depend on Prettier v3, but it is the only outdated package as of now. Changelog

[benmccann]

yes. thanks for the suggestion. PR here: #11037

[benmccann]

Thanks for the suggestion of the migration guide. I'm not sure where such a migration guide would live though? Maybe your comment serves as a migration guide?

[hyunbinseo]

The comment can work as a guide, but it should be added to the documentation.

Similar case: migration to eslint-plugin-svelte docs links to a GitHub comment.

---

I do wish there was an official guide to bumping packages' major versions.

If the user started with create-svelte@3.0.0, these packages are outdated.

Package	Current	Latest	Migration
@typescript-eslint/eslint-plugin (dev)	5.62.0	6.11.0	None
@typescript-eslint/parser (dev)	5.62.0	6.11.0	None
eslint-config-prettier (dev)	8.10.0	9.0.0	None - PR in process
prettier (dev)	2.8.8	3.1.0	pacakge.json scripts, .prettierrc
prettier-plugin-svelte (dev)	2.10.1	3.1.0	pacakge.json scripts, .prettierrc
svelte (dev)	3.59.2	4.2.3	Reference Svelte docs
typescript (dev)	4.9.5	5.2.2	Mention moduleResolution: bundler
eslint-plugin-svelte3	4.0.0	-	Should be uninstalled
eslint-plugin-svelte	-	2.35.0	Should be installed, migration

This will allows users to update their dependencies with confidence.

[dummdidumm]

The place to add that documentation would be the prettier-plugin-svelte repository. It already contains a small section at the bottom of the readme. Happy to accept a PR with more migration instructions.