I received a notification by email for this change: http://www.wikidata.org/w/index.php?title=Q4524&diff=1382958&oldid=1145856 (added Spanish label). On-wiki the summary auto comment is correctly substituted but in the email the summary shows up as:
"Editor's summary: /* wbsetdescription-set:1|es */ especie de mamífero"
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Open | None | T90435 [Epic] Wikidata watchlist improvements (client) | |||
| Open | None | T45044 [Task] Edit auto summary not substituted in email notification | |||
| Open | None | T215422 Migrate Wikibase to use comment_data field instead of SummaryFormatter |
Problem over here is that these emails are plain text ones, while our (formatted) autocomments always consist of html.
We could fix this by either making core's autocomment stuff more flexible so that it also supports a plain text format (sounds very tedious) or by introducing a hook into UserMailer where we can add a custom format for emails (that would be both tedious and messy).
I suggest to WONTFIX this.
With T215422: Migrate Wikibase to use comment_data field instead of SummaryFormatter implemented, the comment_text will be the summary parsed in the content language, so if the mailer uses that (I suppose it does), this bug will be automatically resolved—although the summary will be in content language even if the user’s UI language is different, this is consistent with the rest of the email.