x/build: finish, document Gerrit hashtags for managing open CLs

[bradfitz]

In chat with @andybons @FiloSottile @bcmills and @ianlancetaylor yesterday, I proposed we start using Gerrit's "hashtags" support, now that our hosted Gerrit supports it (notedb support is active for us) and PolyGerrit (the new web UI) supports it.

After discussion, we settled on using tags:

so, how about: "wait-author", "wait-release", "wait-issue", "wait-$PERSON"
where $PERSON is some substring of a name/email in the reviewer set.
and if somebody is named "Issue Release" and their email is issue@release.com, then you have to use their full email in $PERSON
we can mass remove the "wait-release" labels when tree opens

While triaging today, I found we should also add support for:

wait-cl-NNNNN -- this CL is blocked until NNN is resolved

I started looking into adding hashtag support to maintner and gopherbot.

Tracking that work here, then documenting all this on the wiki.

[gopherbot]

Change https://golang.org/cl/106795 mentions this issue: gerrit: add support for hashtags

[FiloSottile]

Also wait-issue-NNNNN. I guess the number can be implicit when the issue is linked from the commit message.

[bradfitz]

@FiloSottile, yup, I just found that too and just tagged an issue with that, for a CL that had an open proposal but wasn't mentioned in the commit message.

[gopherbot]

Change https://golang.org/cl/107297 mentions this issue: maintner: add hashtag mutation accessors on GerritMeta

[gopherbot]

Change https://golang.org/cl/107305 mentions this issue: maintner: track hashtag edits on GerritMeta, make HashtagEdits method faster

[bcmills]

I think I must be missing something, but how do I add hashtags from the Gerrit UI?

[bradfitz]

@bcmills, left bar of the PolyGerrit UI:

[bradfitz]

Or for the old UI, that little icon on the right: