[ci] Automatize the process of backporting about root

[ferdymercury]

Thanks for the suggestion. I am however unsure on how it should handle the release notes, as they are 'different files', not just versions of the same file. See discussion here: #14439

See also https://github.com/sorenlouv/backport

[vgvassilev]

Thanks for the suggestion. I am however unsure on how it should handle the release notes, as they are 'different files', not just versions of the same file. See discussion here: #14439

Most of the backports are fixes that are not probably worth mentioning in the release notes.

[dpiparo]

Thanks for the proposal backed up by a concrete potential solution. I like the idea of having something automated that in case of problems, simply does nothing. One thing that changes though is the squashing.
This is something to discuss. In your opinion, @vgvassilev , what do we loose by automatically squashing commits intended for backports?

[vgvassilev]

Why do we need to squash the commits?

[dpiparo]

I was reading the doc of the action "It can backport rebased and merged pull requests with a single commit and squashed and merged pull requests."

[vgvassilev]

I was reading the doc of the action "It can backport rebased and merged pull requests with a single commit and squashed and merged pull requests."

Ah, ok, well. At that point if we want the bot to help us we should probably do 1 commit by PR for backports. Alternatively, we can implement our own logic - should be no more than 2-3 git commands...

[dpiparo]

I think the squashing of commits is simply a change with respect to what is being done today, it's not negative or a regression per se. I even could see an advantage in having one backport per commit. A good item to be discussed in the team I guess, but this action could be really help us.

[pcanal]

Having different granularity of commits in the main branch and the backport branch may make it harder to do forensic. For example to find out if a change/commit is present in a specific branch or when it was introduced there.