Right now, MediaWiki has 2 pure-PHP engines to produce diffs (there's also
a native PHP extension wikidiff2, but we're not discussing it right now):
* DairikiDiff is what everybody uses, and
* Wikidiff3, and alternative implementation by Guy Van den Broeck that was
around for 8 years but required a configuration change
While less battle-tested, Wikidiff3 offers vastly improved performance on
heavy diffs compared to DairikiDiff. The price, however, is that it makes
certain shortcuts if the diff is too complex. I ran through 100K diffs from
English Wikipedia, and 6% of diffs were different. Lots of changes were
seemingly insignificant but I need your help with determining if it's
really so.
I've built this tool
<https://diff-forge.wmflabs.org/wiki/Special:DiffCompare>[1] to facilitate
the comparison. It displays two diffs from different algorithms side by
side (yeah, it can get too wide, I know:P). Which of them is which is
random. Parts with differences between the implementations are highlighted
in yellow. Below is the diff of differences for the reference. You can vote
with buttons above the diffs, no registration is required. If you see a
catastrophically bad diff please send me the link.
Unless the results are significantly worse, I'd like to go ahead and make
wikidiff3 the only implementation.
[1]
https://diff-forge.wmflabs.org/wiki/Special:DiffCompare
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Best regards,
Max Semenik ([[User:MaxSem]])