hgroup and summary do not accept heading elements

[jwylarsen]

📝 Provide detailed reproduction steps (if any)

1. Enter source editing mode
2. Create an hgroup element and add a heading element
3. Create a details element with a child summary element and add a heading element
4. Toggle back to design mode
5. Toggle back to source mode

✔️ Expected result

Code is preserved as written.

❌ Actual result

hgroup and summary elements are removed

❓ Possible solution

submitting PR to fix this in schema definitions

📃 Other details

• Browser: Chrome, Firefox
• OS: Windows 11, Ubuntu
• First affected CKEditor version: …
• Installed CKEditor plugins: …

---

If you'd like to see this fixed sooner, add a 👍 reaction to this post.

[niegowski]

The problem is in invalid configuration of the GHS hgroup element:

ckeditor5/packages/ckeditor5-html-support/src/schemadefinitions.ts

Lines 340 to 354 in 08270aa

	{
	model: 'htmlHgroup',
	view: 'hgroup',
	modelSchema: {
	allowChildren: [
	'htmlH1',
	'htmlH2',
	'htmlH3',
	'htmlH4',
	'htmlH5',
	'htmlH6'
	],
	isBlock: false
	}
	},

It should be:

{
	model: 'htmlHgroup',
	view: 'hgroup',
	modelSchema: {
		allowIn: '$root',  // <- this is missing
		allowChildren: [
			'paragraph',  // <- this is missing
			'htmlP',  // <- this is missing
			'htmlH1',
			'htmlH2',
			'htmlH3',
			'htmlH4',
			'htmlH5',
			'htmlH6'
		],
		isBlock: false
	}
},

According to MDN it's not a regular container so it does not allow other containers and also it allows only headings and paragraphs inside.

[jwylarsen]

@niegowski That's great. Do you know how to fix the summary element as well? It should accept EITHER $text OR exactly 1 heading element. A little bit trickier.

[Comandeer]

@jwylarsen, the specification allows more than one heading in the summary element:

Phrasing content, optionally intermixed with heading content.

It means that any number of heading elements is valid according to the specification, e.g. the following HTML is valid:

<details>
  <summary>
    <em>Test</em>
    <h2>Test</h2>
    <strong>Test</strong>
    <h3>Test</h3>
  </summary>
  <p>Lipsum</p>
</details>

Validator agrees.

[jwylarsen]

@Comandeer Good to know! I was just going off of what MDN said. Either way, I've submitted a PR to address both hgroup and summary issue here: #16951