Appearance of a onebox in the edit history

zogstrip · September 12, 2026, 3:30pm

thanks for the report @Moin

diffing is hard but will hopefully be better once this gets merged

github.com/discourse/discourse

FIX: Don't wrap whitespace between tags in revision diffs (#43604)

main ← fix-revision-diff-whitespace-tokens

merged 11:46PM - 12 Sep 26 UTC

ZogStriP

+77 -53

Previously, `DiscourseDiff` wrapped every added text token in `<ins>`, including… the formatting whitespace between tags. Inside a GitHub onebox, whose body is a CSS grid with `display: contents` rows, those extra elements became grid items and displaced the title into the 2.5em icon column, where it wrapped one character per line. This change appends whitespace-only text nodes to the preceding tag token so they can never become elements. It also fixes three things found alongside it: - closing tags were given a class, emitting `</h4 class="diff-ins">` - `class=` was matched inside attribute values, so `[text](url "class=foo")` raised `NoMethodError` and returned a 500 from the revisions endpoint - the raw view tinted the whole cell even when only some words changed, hiding the word-level markers underneath, and quote backgrounds hid the highlight on an inserted or removed quote Reported in https://meta.discourse.org/t/appearance-of-a-onebox-in-the-edit-history/412207

Topic		Replies	Views
Inconsistent internal onebox spacing UX	7	1279	May 13, 2022
Width of edit history with formated code on moblie UX fixed , revisions	3	554	October 2, 2023
HTML diff view is a bit broken Feature	6	1993	June 15, 2025
GitHub onebox wrongly removes identation inside the curly braces Bug	4	1298	March 7, 2019
Twitter quote-tweets not shown in oneboxes Feature	15	2403	July 18, 2019

Appearance of a onebox in the edit history

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