add stale gha

[bjlittle]

🚀 Pull Request

Description

This PR adds the stale GHA in order to help maintain a healthy issues and prs backlog.

---

Consult Iris pull request check list

[bjlittle]

I guess the proposed days-before-stale and days-before-close values are the main thing up for debate.

If it helps, here is a plot of the number of issues that would not be considered stale for the given dates or days since now (3 Aug 2021) e.g., for the proposed days-before-stale of 1000 which is 7 Nov 2018, approximately 159 issues would remain not marked as stale out of 295.

[jamesp]

I think this is a great idea. I'd be all in favour of a shorter days-before-stale. Realistically, if we haven't addressed it in 365 days it's probably never going to get addressed, and the project will have moved on significantly from this point of raising.

[bjlittle]

@jamesp Personally, happily move south of 1000... the associated GH Discussion seeded the initial value.

i.e., a days-before-stale of 500 (21 Mar 2020) would leave 70 issues open.

I'm happy to go with the crowd on this one, as long as there isn't too much protracted debate. I think we just need to make a call. At the end of the day closed issues and prs can be re-opened... it's not the end of the world, but from our perspective as maintainers we could actually really own the issues backlog for the first time in many, many years.

... we'd just need to commit to keeping on top of it, but that's on us as maintainers.

[rcomer]

Over on the discussion, there was talk of starting with a 3 year lead, and then gradually reducing. I think starting with a smaller number of stale issues makes sense, because we can see what kind of activity (if any) is generated by people re-engaging. It would be a shame if someone did re-engage but we didn't have time to address their comments.

On the gap between stale and closed, I would have said at least a month, as it gives time for people who are on holiday or otherwise away. So 28 days seems OK to me, but I wouldn't want to go any lower.

[bjlittle]

@jamesp Did you want an associated whatsnew entry? I'm really not fussed...

[jamesp]

No I don't think it's necessary, thanks @bjlittle!