Use an actual HTML parser: unexpected behavior around nested `<style>` / `script` tags

[Prinzhorn]

Obligatory https://stackoverflow.com/a/1732454/1422124

Took me a while to track this down, because prettier was also swallowing the error message (I'll investigate and open an issue in the appropriate repo).

Essentially the offending code I had was something like this (adapted from https://github.com/rmariuzzo/react-new-window/blob/2417b08352f34f193cc5e69524379fb70ccecf5b/src/NewWindow.js#L195 for svelte):

<script>
  Array.from(document.styleSheets).forEach(styleSheet => {
    // For <style> elements
    let rules;
    try {
      rules = styleSheet.cssRules;
    } catch (err) {
      console.error(err);
    }
    if (rules) {
      //...
    } else if (styleSheet.href) {
      // for <link> elements loading CSS from a URL
      ...
    }
  });
</script>

<style>...</style>

<div>...</div>

The comment For <style> elements inside the JavaScript causes the regex based parser to think it's a style tag.

Sure it's an edge case, but it might be worth considering switching to an actual HTML parser. Maybe svelte core can be imported into this plugin? I'm sure they're handling this already.

Thanks for the plugin by the way!

[Prinzhorn]

I'll submit a PR to upgrade the regex as a workaround. An actual parser might be overkill anyway.

Edit: This is a damn rabbit hole (shockingly). I thought we could adjust the regex to only match tags at the start of a line, but that would still not allow closing tags anywhere inside the content. So Chomsky won once again, I am defeated. I'm interested in what you are suggesting and if there is an easy way to integrate svelte's own parsing in here.

Anyway, the main issue I guess is that I didn't get any meaningful error message at all. Otherwise I'd just removed the comment ¯_(ツ)_/¯

[dummdidumm]

Also causes this behavior:

Input:

{@html `<style class="block">
...
</style>`}

Output:

{@html `<style class="block ✂prettier:content✂="LmFuaW1hdGlvbk5hbWUgewogI..."></style>`}

Workaround: Hide it in a nested string.

{@html `<${'style'} class="block">
...
</style>`}

(from https://github.com/sveltejs/prettier-plugin-svelte/issues/59#issuecomment-643336817)

[codingwithchris]

@dummdidumm @Prinzhorn This issue still exists as of:

"prettier": "^2.6.2",
"prettier-plugin-svelte": "^2.7.0",

Example:

Input

import { getCssText } from '@tokens';
<svelte:head>
	{@html `<style>${getCssText()}</style>`}
</svelte:head>

Output

import { getCssText } from '@tokens';
<svelte:head>
    {@html `<style ✂prettier:content✂="JHtnZXRDc3NUZXh0KCl9"></style>`}
</svelte:head>

[secondfry]

How come this be an enhancement tho, seems like a critical bug.

[tadeohepperle]

I also have this issue. Are there any news on this? How can I disable this behavior? It's potentially fucking up code pretty badly that could end up in production, just by accidentally saving with prettier.

[justingolden21]

Can't add dynamic ld json schema with this bug that's been here for 3+ years

[justingolden21]

Minimum reproducible

{@html `<style>${'a'}</style>`}

To confirm, this is caused by the vs code plugin for prettier.

[dummdidumm]

Do you have the latest version of the plugin/extension installed? Can't reproduce this given your snippet. If there's something that can be reproduced, please open a separate issue for that.

[digvijayad]

@dummdidumm For me, the components' top level script tag was converted to prettier:content Input:

<script>
    import ApplicationLogo from "@/Components/ApplicationLogo.svelte";
    import { inertia } from "@inertiajs/svelte";
    let className;
    export { className as class };
</script>

output:

<script
    ✂prettier:content✂="CiAgICBpbXBvcnQgQnJlZXplQXBwbGljYXRpb25Mb2dvIGZyb20gIkAvQ29tcG9uZW50cy9BcHBsaWNhdGlvbkxvZ28uc3ZlbHRlIjsKICAgIGltcG9ydCB7aW5lcnRpYX0gZnJvbSAiQGluZXJ0aWFqcy9zdmVsdGUiOwoKICAgIGxldCBjbGFzc05hbWU7CiAgICBleHBvcnQgeyBjbGFzc05hbWUgYXMgY2xhc3MgfTsK">{
}
</script>

Can reproduce using PhpStorm in 2 different scenarios:

1. Reformat Whole File with prettier plugin installed using the Ctrl+Alt+Shift+L shortcut. Not via Ctrl+Shift+Alt+P To be specific only happens if Optimize Imports option is checked.

2. Using Git Commit Checks with either Reformat code or Optimize Imports options checked.

I have disabled those options for myself, but hopefully that's something. I can put this into a new issue, but I already see 3 issues with similar content.

[abdelfattahradwan]

@dummdidumm For me, the components' top level script tag was converted to prettier:content Input:

<script>
    import ApplicationLogo from "@/Components/ApplicationLogo.svelte";
    import { inertia } from "@inertiajs/svelte";
    let className;
    export { className as class };
</script>

output:

<script
    ✂prettier:content✂="CiAgICBpbXBvcnQgQnJlZXplQXBwbGljYXRpb25Mb2dvIGZyb20gIkAvQ29tcG9uZW50cy9BcHBsaWNhdGlvbkxvZ28uc3ZlbHRlIjsKICAgIGltcG9ydCB7aW5lcnRpYX0gZnJvbSAiQGluZXJ0aWFqcy9zdmVsdGUiOwoKICAgIGxldCBjbGFzc05hbWU7CiAgICBleHBvcnQgeyBjbGFzc05hbWUgYXMgY2xhc3MgfTsK">{
}
</script>

Can reproduce using PhpStorm in 2 different scenarios:

1. Reformat Whole File with prettier plugin installed using the Ctrl+Alt+Shift+L shortcut. Not via Ctrl+Shift+Alt+P To be specific only happens if Optimize Imports option is checked.
2. Using Git Commit Checks with either Reformat code or Optimize Imports options checked.

I have disabled those options for myself, but hopefully that's something. I can put this into a new issue, but I already see 3 issues with similar content.

Oh, THANK YOU! This has been bugging me for weeks!

[NeilOnasch0402]

Should be treated as a bug, not an enhancement