EventLogging's main session ID is supposed to persist until a user has been inactive for 30 minutes. However, I've noticed that mw.eventLog.id.getSessionId() returns a different ID on every pageview, no matter how short the interval between them.
I've tested this on Firefox 103.0 and Safari 15.5 (17613.2.7.1.8) and the result is the same.
| Subject | Repo | Branch | Lines +/- | |
|---|---|---|---|---|
| storage: Return value retrieved from cookie jar | mediawiki/extensions/EventLogging | master | +72 -1 |
Hmm, it looks like the sessionTick values in the cookie persist fine; it's just that the function is returning a separate session ID that is different on every pageview. I'm pretty sure that's not supposed to happen. So maybe sessionTick itself isn't impacted but other schemas that use the session ID are?
Oh wait, there's mw.eventLog.id.getSessionId() and mw.user.sessionID()? And they're different? 😵💫
So it seems like mw.user.sessionID() is the "old" session ID which lasts until the browser is closed, and mw.eventLog.id.getSessionId() is the "new" session ID which corresponds. the session tick instrumentation. For a minute, I thought I was just looking at the wrong one, but no, mw.eventLog.id.getSessionId() is the one I want and should be persisting between pages.
Hmm, it looks like:
So even if this is real, the impact is pretty limited. It should still be fixed, though.
MetricsClient has a bug in its storage helper definition.
core.storage = {
get: function ( name ) {
mw.cookie.get( 'el-' + name );
},
set: function ( name, value ) {
mw.cookie.set( 'el-' + name, value );
},
unset: function ( name ) {
mw.cookie.set( 'el-' + name, null );
}
};Note the lack of a return in the get method. Means it never thinks it has a sessionid stored...
Change 820701 had a related patch set uploaded (by Phuedx; author: Phuedx):
[mediawiki/extensions/EventLogging@master] storage: Return value retrieved from cookie jar
Looking at rEEVL01fb701db1c7: Sampling logic and session/pageview id support, it appears that the bug was introduced at the same time the method was. Fortunately, as @DLynch points out, it's simple enough to fix.
Change 820701 merged by jenkins-bot:
[mediawiki/extensions/EventLogging@master] storage: Return value retrieved from cookie jar
☝️ https://gerrit.wikimedia.org/r/820701 should have been fully deployed by the end of Thursday, 4th August 2022.
I happen to be doing checks on the same data again and this problem is clearly fixed.
(I did just discover a much less common case where the ID seems to persist too long, but that's a song for another ticket 😊)