Find alternative to backport bot

[kbevers]

The backporting bot stopped working a week or two ago. This is not ideal since it has been a valuable tool since we installed it. After recent changes the bot now works as a GitHub Action. According to tibdex/backport#33 this has the unfortunate side effect that the bot can only backport PR's from brances on the main repository and not from forks. Judging by the comments of the developer of the bot this doesn't seem like something that can be fixed (limitations in GitHub functionality I believe). We need to find an alternative.

A bit of googling reveals a few possible options:

1. https://github.com/MeeseeksBox/MeeseeksDev (suggested by @QuLogic in Backport #1333 on 6.0 #1334)
2. https://github.com/electron/trop
3. https://github.com/chainer/backport

Option 1 seems rather complicated and can do more than just backport PRs. Options 2 and 3 are more specific in their use but unfortunately doesn't offer much help in terms of setup. Both include an install section but doesn't go in details with where to install. I assume in a CI script but I have not looked further into that yet.

[3nids]

have you seen https://github.com/spring-io/backport-bot

[kbevers]

Having looked into this again, I think the best thing we can do right now is to install this fork of the original backport bot. The only downside I can see is that it requires a separate GitHub user that can open pull requests from a fork of the PROJ repository.

As far as I can tell this is what QGIS is doing and it seems to be working alright.

Unless someone has a better solution to this I'll set up a PROJ-BOT user soon and get this backporting business up and running again. Since several OSGeo projects are having the same issue we could also consider calling it OSGeoBot and let it be used by GDAL and other friendly projects. Thoughts?

[rouault]

Looking at qgis-bot, it seems that the bot appears as the commit author. Which can be annoying when doing archeology and trying to figure out who added what. That said, as it is only for maintainance branches, by matching the commit message with the ones from master, one can retrieve the original commit & author.

[kbevers]

Yeah, that's not great. Basically, what we had was perfect. And it seems that is the opinion of GDAL and QGIS as well. Perhaps we should try to fix this in unison? If this is helpful for several projects I reckon the board would be willing to allocate some funds for developing a proper bot. @rouault @3nids what do you think about that idea?