Babel plugin doesn't add PURE comment in latests babel

[paul-sachs]

Current behavior:

The current babel plugin seems to work fine for everything except the /* #PURE */ comment that should be seen.

To reproduce:

1. See custom repo: https://github.com/paul-sachs/emotion-babel-bug
2. Run npm install and npm run build
3. Output will not have PURE comment prefixed to styled component

Expected behavior:

All styled blocks should be prefixed with PURE comment

Environment information:

• "react": "^17.0.2",
• "@emotion/babel-plugin": "^11.7.2"
• "@emotion/core": "^11.0.0",
• "@emotion/styled": "^11.6.0",

[srmagura]

Thanks for the report. It's odd, the line that adds the PURE comment is getting hit, but the comment is not actually getting added. I can look at this over the weekend, though I'm not sure if I can fix it.

BTW, @emotion/core is deprecated and currently does nothing.

[paul-sachs]

I ended up fixing it with a yarn patch. Basically just did ‘reference.parentPath.addComment(..)’ but I wasn’t sure that was the correct solution.

…

On Wed, Jan 19, 2022 at 1:55 PM Sam Magura ***@***.***> wrote: Thanks for the report. It's odd, the line <https://github.com/emotion-js/emotion/blob/main/packages/babel-plugin/src/styled-macro.js#L108> that adds the PURE comment is getting hit, but the comment is not actually getting added. I can look at this over the weekend, though I'm not sure if I can fix it. — Reply to this email directly, view it on GitHub <#2619 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACXLLAALHAEVQFTJGJ6FVQ3UW4CL5ANCNFSM5MKN2FTQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[srmagura]

Awesome. @Andarist is that the correct solution?

[Andarist]

It might be the correct solution but that also means that something has changed on the Babel side of things. In general, comments are really wonky in AST because based on a source file it's really uncertain to which AST node a particular comment belongs. So perhaps the Babel generator (from AST to text) changes its logic somehow and what we have been adding became swallowed now?

We should upgrade all Babel deps and check if any of our snapshots change.