Prettier has been updated to 3.7.0, this plugin gives error with this version of Prettier

[ExoticGamerrrYT]

Describe the bug
After updating Prettier to version 3.7.0, formatting .svelte files using prettier-plugin-svelte fails with a runtime error.

To Reproduce
Steps to reproduce the behavior:

1. Install Prettier 3.7.0 and prettier-plugin-svelte@3.4.0.
2. Run prettier --write . on a project with .svelte files.

Expected behavior
Svelte files should be formatted correctly without throwing errors.

Actual behavior
Prettier throws the following error:

TypeError: getVisitorKeys is not a function or its return value is not iterable
at recurse (index.mjs:17713:24)
at printEmbeddedLanguages (index.mjs:17683:3)
at printAstToDoc (index.mjs:17792:9)
at async coreFormat (index.mjs:18171:14)
at async formatWithCursor (index.mjs:18384:14)
at async formatFiles (internal/legacy-cli.mjs:5831:18)
at async main (internal/legacy-cli.mjs:6220:5)
at async Module.run (internal/legacy-cli.mjs:6163:5)

Additional context

• prettier-plugin-svelte version: 3.4.0
• Prettier version: 3.7.0
• Svelte version: 5.x

This issue does not occur with Prettier 3.6.2. It appears to be a compatibility problem with the newly released Prettier 3.7.0.

[Greenheart]

This actually affects most prettier plugins and is not specific for prettier-plugin-svelte.

The cause seem to be a change in prettier@3.7.0 prettier/prettier#18353.

Related, this also affects the Prettier VS Code extension: prettier/prettier-vscode#3825

[sacrosanctic]

For what it's worth, if you rearrange the plugins, it works.

"plugins": ["prettier-plugin-tailwindcss, "prettier-plugin-svelte"],

[fisker]

For what it's worth, if you rearrange the plugins, it works.

"plugins": ["prettier-plugin-tailwindcss, "prettier-plugin-svelte"],

If this works, can prettier/prettier#18072 the cause? I thought the issue was about plugin loading.

[bigmac44]

Noting this same issue in the tailwind plugin:

tailwindlabs/prettier-plugin-tailwindcss#417

[ExoticGamerrrYT]

Update

I’ve tested this again using Prettier 3.7.3, and the crash still happens with the same getVisitorKeys is not a function error.

However, I found something new:

• When the plugin order in .prettierrc is Svelte first, then Tailwind, it crashes:

  "plugins": ["prettier-plugin-svelte", "prettier-plugin-tailwindcss"]

• When I reverse the order, putting Tailwind first and Svelte second, it works:

  "plugins": ["prettier-plugin-tailwindcss", "prettier-plugin-svelte"]

I’m not sure why changing the order prevents the error, but the issue is reproducible on a clean SvelteKit project.

Just updating this issue with the latest findings in case it helps diagnose the problem.

[blueambr]

@ExoticGamerrrYT If you change the order of the plugins, tailwind plugin stops working, so that might be why it stops creating errors.

The solution for now is to revert prettier version to 3.6.2 and wait for this to be fixed by maintainers.

[ExoticGamerrrYT]

@blueambr oh did not notice that, but yes i will use 3.6.2 meanwhile 😄

[thecrypticace]

I've released v0.7.2 of prettier-plugin-tailwindcss which fixes the compatibility issue with this plugin when using Prettier v3.7+