1427059 - MDN generates horribly inefficient diffs

Status: RESOLVED WONTFIX

(developer.mozilla.org Graveyard :: General, enhancement, P5)

Description

[Evgeny Kapun]

What did you do?
================
1. Edit a page.
2. Open a diff of my edit, to see what exactly I changed.

What happened?
==============
A diff looked horrible. And I'm not just talking of visual horribleness, like the diff being wider than my (quite wide) screen and line breaks appearing in the middle of words. What I'm talking about is the way the diff is generated. A diff is only supposed to highlights the parts that changed. A diff generated by MDN, however, can highlight an entire large paragraph because of a trivial change like replacing " " with " " in one place. Sometimes, it matches fragments of texts in bizarre and clearly suboptimal fashion. Look at an example [1] to see what I'm talking about.

What should have happened?
==========================
A diff should have looked much better, like the one generated by Wikipedia [2]. Not only it is better visually, the algorithm that they use seems to be much more efficient.

Is there anything else we should know?
======================================
For comparison, I took a diff of MDN edit I made [1], and made Wikipedia generate a diff between the same pair of documents [2].

[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty$compare?from=1314469&to=1340214
[2] https://en.wikipedia.org/w/index.php?diff=817089162

Comment 1

[BMO Automation]

MDN Web Docs' bug reporting has now moved to GitHub. From now on, please file content bugs at https://github.com/mdn/sprints/issues/ and platform bugs at https://github.com/mdn/kuma/issues/.