1795904 - Textarea scrollHeight incorrect when dynamically added and overflow: hidden

Status: RESOLVED DUPLICATE of bug 1787062

(Core :: Layout: Scrolling and Overflow, defect)

Description

[Ilya Radchenko]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36

Steps to reproduce:

Dynamically add a textarea (on button click)

• Create it on click
• Set overflow: 'hidden'
• Add to body
• Set value to something that is more then one line, e.g. '1\n2\n3\n'

Reproduction https://codepen.io/tgknownasilya/pen/wvjboOo
Code from the pen:

// Test code
function show() {
  const hiddenTextarea = document.createElement('textarea');

  hiddenTextarea.style.overflow = 'hidden';

  document.body.appendChild(hiddenTextarea);

  hiddenTextarea.value = '1\n2\n3\n';
  console.log('3 lines', { scrollHeight: hiddenTextarea.scrollHeight });

  hiddenTextarea.value = '1\n2\n3\n';
  console.log('3 line',  { scrollHeight: hiddenTextarea.scrollHeight });
}

Actual results:

Initial value causes incorrect scrollHeight. Above code snippet logs:

3 lines
Object { scrollHeight: 36 }
3 line
Object { scrollHeight: 68 }

Expected results:

Expect it to log

3 lines
Object { scrollHeight: 68 }
3 line
Object { scrollHeight: 68 }

(note that this is correct in Chrome)

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Layout: Scrolling and Overflow' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Ilya Radchenko]

Note that on Firefox 103 on Linux this issue doesn't exist

Comment 3

[Timothy Nikkel (:tnikkel)]

Note its the "Remove useless ProcessPendingRestyles call" changeset that regressed this.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

:emilio, since you are the author of the regressor, bug 1778983, could you take a look? Also, could you set the severity field?

For more information, please visit auto_nag documentation.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

This is basically bug 1787062... It's an issue with editor initialization being async, see there. The good thing is that working around it is trivial (just add another layout-affecting getter call, like scrollHeight to flush the changes made by editor init.