arc land Changes

The major user-facing change this week is a rewrite of arc land behavior in Git. T9657 has a fairly complete summary.

Users have a large variety of creative, novel ways of using git which we should now better accommodate. The most common case of this is landing a branch onto itself, but essentially every plausible workflow should now enjoy rich support.

Spinning Icons

@chad made the icon for landing a revision spin in D14351, which is easily the best change we've made in a while.

In light of this, I added support for spinning any icon with {icon ... spin}:

New Migrations Table

This week adds a new "Migrations" table to the changelog. Some installs would like more ability to predict how much downtime an install will require for migrations. Although we can't really guess this very accurately (installs routinley report migration times that vary by something like four orders of magnitude), we can at least show which migrations occur, how long they took on this install, and any risks we anticipate.

We generally expect migrations to be approximately proportional to datasize, so if a migration took 5 seconds on this install and you have 10x as much data and comparable hardware, it should take about 50 seconds. In practice, this doesn't seem to hold up very well, but hopefully this table is useful in at least ballparking the impact of migrations.

Land Revision

This feature is now in better shape and we've been landing many of the upstream changes with it for several weeks without problems.

Ambitious installs now stand a reasonable chance of configuring and using this feature on their own. T182 has details and pointers to documentation. Note that the feature still has some major limitations (also detailed in T182).

Upcoming

I'm hoping to get ApplicationEditor (T9132) underway this week while giving T182 some time to settle and maybe get some initial feedback from ambitious installs.

Nuance (T8783) and updates to Projects (T9378) and Phriction (T9379) are still the plans for the remainder of the year.