From mid-July to mid-October the game's repository took in about a hundred commits a day, 397 on the busiest. A project moving that fast either has rules that hold it together or it falls apart. These are the rules.
No fix-later notes without a ticket
Code is full of notes that say a thing will be done properly later. Most never are. Since August 11th, a note like that is only allowed if it names the ticket that will close it, and a checker refuses any new one that does not. The inherited code still carries a large backlog of untracked notes; the rule applies to every new line.
The same goes for holds, the places where code from the original game is kept waiting on a piece that has not landed yet. Since September 12th a check flags a hold as soon as its missing piece arrives, so nothing stays held by accident. One of the commits behind these checks put the reasoning in a line:
A detector with no negative control is just a thing that says yes.
Trains
Reviewed changes do not merge one at a time. They ride together on a branch, a train, which gets one full judgment: the build, the checkers, the script tests and the frame oracle, which compares rendered frames against approved reference pictures. If the train passes, everything on it merges at once.
The first train ran on September 16th, titled to merge the twelve green changes of the day in one pass. From September 24th the pipeline posts its verdict on the train itself, and a train merges itself once every check is green. By mid-October 257 trains had merged, and the frame oracle had grown from 184 scenes to 797.
By the numbers
As of October 17th the game's repository has merged 2,234 changes and closed 1,441 issues, 1,335 of them by landing the work they asked for. 252 are still open.
Alex (maintainer, and a mechanical engineer by trade)