If your team uses mw.user.sessionId() for instrumentation, a recent change
to MediaWiki could impact your numbers.
The new patch <https://gerrit.wikimedia.org/r/#/c/mediawiki/core/+/572011/>
changes
the way that session IDs work, bringing their behavior closer to other
platforms that many of us are familiar with.
The value returned from mw.user.sessionId() will now:
- be the same in different tabs of the same browser process
- be the same in different windows of the same browser process
- be forgotten once the browser process ends
Since 2017, values returned from mw.user.sessionId() have only been
constant within the same browser tab, and only lasted until the tab was
closed. This had gone unnoticed until recently. See T223931
<https://phabricator.wikimedia.org/T223931> for more details. This patch
restores pre-2017 behavior.
If you have any questions about the change, or if you notice any
irregularities in your data or instrumentation, reach out or tag jlinehan,
mpopov, or the Better Use of Data topic on Phabricator.
-Jason