htmlClass pattern validation is too restrictive

[thomas-kl1]

Resource: https://www.w3.org/TR/CSS22/syndata.html
Part 4.1.3

In CSS, identifiers (including element names, classes, and IDs in selectors) can contain only the characters [a-zA-Z0-9] and ISO 10646 characters U+0080 and higher, plus the hyphen (-) and the underscore (_); they cannot start with a digit, two hyphens, or a hyphen followed by a digit. Identifiers can also contain escaped characters and any ISO 10646 character as a numeric code (see next item). For instance, the identifier "B&W?" may be written as "B&W?" or "B\26 W\3F".

Preconditions (*)

1. Add a new container in your layout
2. Add a htmlClass with a character like "@"

Steps to reproduce (*)

1. Add a new container in your layout
2. Add a htmlClass with a character like "@"

Expected result (*)

1. The container is added to the dom with the correct class attribute value

Actual result (*)

1. Layout validation fails because it says the character is not allowed

---

Please provide Severity assessment for the Issue as Reporter. This information will help during Confirmation and Issue triage processes.

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[thomas-kl1]

@magento I am working on this

[ihor-sviziev]

Hi @thomas-kl1,
Could you describe what is the use case of using the @ symbol in the class names? Magento definitely not supporting, but I don't think there is some valid use case for using such things.

[m2-assistant]

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[thomas-kl1]

@ihor-sviziev there is many css framework that use "@ " in classnames. Anyway the current validation it too much restrictive regarding this ressource https://www.w3.org/TR/CSS22/syndata.html

There is no valid point to prevent using other characters and some could be easily escaped thanks to the escaper object.
Many projects I work on, have to use patches to override this rule or to use alternative blocks and templates, which is redundant and could be avoided

[ihor-sviziev]

TBH I never saw that "at" symbol used in the class names, I also didn't see it in any CSS frameworks, and I personally don't think it's a good idea because it will confuse people. Maybe you could provide some examples?

I still believe this issue having a too-small amount of people. Probably priority for this issue should be P4, which is the lowest priority.

[thomas-kl1]

You missed the point. The point: https://www.w3.org/TR/CSS21/syndata.html#value-def-identifier

If you need the full standard documentation, there's the links:

• https://www.w3.org/TR/CSS/#css
• https://www.w3.org/TR/css-syntax-3/#syntax-description
• https://www.w3.org/TR/css-syntax-3/#style-rule
• https://www.w3.org/TR/css-syntax-3/#parsing
• https://www.w3.org/TR/selectors-4/#class-html
• https://www.w3.org/TR/selectors-4/#id-selector

I never saw that "at" symbol used in the class names, I also didn't see it in any CSS frameworks

That's your thought, it doesn't make it true. Some in-house and proprietary frameworks could use chars that are not part of the current rules:

• [a-zA-Z][a-zA-Z\d\-_:]*
• [a-zA-Z][a-zA-Z\d\-_]*(\s[a-zA-Z][a-zA-Z\d\-_]*)*

I personally don't think it's a good idea because it will confuse people

That's also your opinion, developers are free to use it or not, so there is no confusion either.

I don't think there is some valid use case for using such things

Since some major companies are using it, it's pretty much valid to me, so it's still opinionated to me

What's the reason behind those Magento's rules? What is the legitimate design to write these regex patterns?
A framework should be a friendly tool for developers to help them to quickly solves common problems. Here it adds a constraint without any reasons.

Also I've used the "@" character as an example, but it could be any that follows the standard:

In CSS, identifiers (including element names, classes, and IDs in selectors) can contain only the characters [a-zA-Z0-9] and ISO 10646 characters U+00A0 and higher, plus the hyphen (-) and the underscore (_); they cannot start with a digit, two hyphens, or a hyphen followed by a digit. Identifiers can also contain escaped characters and any ISO 10646 character as a numeric code (see next item). For instance, the identifier "B&W?" may be written as "B&W?" or "B\26 W\3F".

We could agree or disagree to use such characters for identifiers, but we might follow the standards. The decision to use such characters is scoped to project, not to the framework.

[ihor-sviziev]

@sivaschenko @sidolov @gabrieldagama, could you review this issue and comment,s and provide your opinion?
Thank you!

[MeCapron]

Hello,

I'm reopening this issue because it is also a problem for us.

It makes even more sense now that Tailwind is around the place for a lot of projects. The defined xsd is not scalable and do not take in account technologies or evolutions.

As @thomas-kl1 mentioned, this is not only concerning the @ symbol but all symbols accepted by the W3 standards.

Why can't we make this evolve?

[thomas-kl1]

at least colon is now accepted :') 34115de

[MeCapron]

Related to : #36452 which may fix this issue

[engcom-November]

Hi @thomas-kl1 ,
Thanks for the report and collaboration! We have tried to reproduce this issue in Magento 2.4-develop branch but the issue is not reproducible.
We have followed the below steps:

1. Added a new container in your layout

Container added in app/code/Magento/Ui/view/base/templates/control/button/default.phtml

2. Added a htmlClass with a character like "@"
   We can able to see the container is added to the dom with the correct class attribute value
   Kindly recheck the issue on Magento 2.4-develop instance and elaborate missing steps if the issue is still reproducible.
   

[m2-assistant]

Hi @engcom-November. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

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  - Add the comment @magento give me 2.4-develop instance to deploy test instance on Magento infrastructure.
  - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
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[thomas-kl1]

@engcom-November sure after 2 years without updates, maybe it have been fixed somewhere by somebody...

[ihor-sviziev]

Hi @engcom-November,
From your screenshot I see you don't have attribute "class", but you have "htmlClass", I bet that's the reason why it work for you.
In general, in the page I would expect having something like <div class"w-screen left-1/2 right-1/2 mx-[-50vw] relative @something">...</div>

[thomas-kl1]

Good catch @ihor-sviziev I didn't checked the screenshot 😅

[engcom-November]

Hi @ihor-sviziev / @thomas-kl1 , Thank you for the response.
We have tried to reproduce the issue in Magento 2.4-develop branch and the issue has been reproducible for us. We have followed the below steps:

1. Open any front end file, for example considered /app/code/Magento/catalog/view/frontend/layout/catalog_product_view.xmlChange the
2. html class name to htmlClass="w-screen left-1/2 right-1/2 mx-[-50vw] relative @something"
3. Deploy static content and flush cache
4. Front end - Open the Product details page from any catagory.
   Were getting an error page
   

Hence confirming the issue.

[github-jira-sync-bot]

✅ Jira issue https://jira.corp.adobe.com/browse/AC-7854 is successfully created for this GitHub issue.

[m2-assistant]

✅ Confirmed by @engcom-November. Thank you for verifying the issue.
Issue Available: @engcom-November, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.

[thomas-kl1]

Fixed by #36452