QA

In reminder comment add a text like "Expect the next reminder at the earliest $time_next" with $time_next being current time + 2 * current difference used

I'm not sure that make sense if we are considering all comments, not only auto-review comments:

Comment n-2 (user-x):    March 1st
Comment n-1 (user-y):    March 3rd (2d)
Comment n (auto-review): March 7 (4d)
  "Expect the next reminder at the earliest in 8 days"
Comment n+1 (user-x): March 8 (1d)

Now the interval is set back to 1 day, so auto-review would wait 2 days, so the comment about 8 days is wrong.

Question about redmine: Should field changes without a text comment be considered comments?

tinita wrote:

In reminder comment add a text like "Expect the next reminder at the earliest $time_next" with $time_next being current time + 2 * current difference used

I'm not sure that make sense if we are considering all comments, not only auto-review comments:

Comment n-2 (user-x):    March 1st
Comment n-1 (user-y):    March 3rd (2d)
Comment n (auto-review): March 7 (4d)
  "Expect the next reminder at the earliest in 8 days"
Comment n+1 (user-x): March 8 (1d)

Now the interval is set back to 1 day, so auto-review would wait 2 days, so the comment about 8 days is wrong.

That's why we have the max in max((time_last - time_second_to_last // 0), initial_time_interval), in your example max(($time_current - 1d), 14) = 14 with 14 being our initial_time_interval. So I don't think that the interval is set back. The good effect is that basically any non-auto-review comment that are posted earlier than the next expected reminder would reset the exponential backoff if I understand my/our algorithm correctly so we would again have reminder comments sooner which I consider a good thing. For a stale bug we want less frequent reminders, for an active bug we want more frequent information flows.

tinita wrote:

Question about redmine: Should field changes without a text comment be considered comments?

Yes. Or more correctly what we look at anyway are "any changes in the history", not just comments. Compare to how the tabs in redmine interface are called. By default in History there is "All" selected with the option to show only "Notes" aka. "Comments" and "Changes".

any non-auto-review comment that are posted earlier than the next expected reminder would reset the exponential backoff

Well, take my example and make it 14 days, 28 days etc. instead.
And you say it yourself, it would reset the backoff.
But then the previous comment "Expect the next reminder at the earliest in x days" will be wrong.
It would be correct to say "Expect the next reminder at the earliest in x days if noone comments earlier".