Duplicate detection already labelled and commented on new issues, and then
closed them outright at 0.85 title similarity. That gave the reporter no chance
to push back, and a title-similarity match is not strong enough evidence to
close on its own.
Detection now only flags. A new daily sweep closes a flagged issue three days
later, and only if nobody engaged with the flag. Replying to it, thumbs-downing
it, or applying an opt-out label all keep the issue open. The notice says all of
that up front, so the reporter knows what happens and how to stop it.
The two workflows hand off through an HTML marker in the comment body rather
than its prose, so rewording the notice cannot silently break the sweep. The
sweep lists by label instead of walking the whole backlog: 1663 open issues
against 23 carrying the label meant a comments request each, which would burn
the Actions token's hourly budget for a handful of matches.
Candidates are taken as the lowest issue number, not the first one listed. The
detector orders by score rather than age, so the first candidate can be newer
than the issue being closed, and folding an original report into a later one is
backwards. An issue whose only candidates are newer is skipped.
Closures use state_reason=duplicate rather than not_planned, which reads as
"see the other issue" instead of "we are not doing this".
Also drops {{html_url}} from the notice. The detection action only exposes
number, title and accuracy, so that placeholder had been rendering empty and
every "similar issue" link in the comment pointed nowhere.
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