Use position for element dom_id

[tvdeyen]

What is this pull request for?

Change the DOM ID of elements to use position instead of id

We cannot use the id, because that will change if publish the page. The position will be the same across versions and combined with the name it is unique on each page.

Deprecate element_dom_id helper

Use element.dom_id instead.

Deprecate full_url_for_element helper

Please element.dom_id and pass it as anchor to your URLs.

Refs #2354

Checklist

• I have followed Pull Request guidelines
• I have added a detailed description into each commit message
• I have added tests for the changes

[mamhoff]

What's with the position of nested elements? Could there be conflicts?

[tvdeyen]

What's with the position of nested elements? Could there be conflicts?

Yes, if the same element is also nested into another element. We could add the parents dom_id.

Also, I thought ultimately we could add a DomId class that people could configure to their needs.

[tvdeyen]

@mamhoff the parent elements dom_id (if present) is now included. #2373 introduces the possibility to use a custom dom id class.

[dbwinger]

@tvdeyen this breaks links using anchors, right?

[tvdeyen]

@dbwinger no, it makes them work again. It stopped working after we introduced page versions and didn't realized that the database ID used as DOM ID does not work anymore.

Existing links have been broken since then and this fixes the issue for new links created.

This behavior is now configurable and can be adjusted to your liking as well.

Hopefully this works for you

[dbwinger]

Got it. Yes, this will work. I think I can easily migrate my broken links.