[guscost]

But if the time needed to test and deploy a change is so ludicrous, it seems like you'd rarely get a big-enough window to rerun your tests before the upstream changes again. Either people are merging in unstable code, or the release lifecycle is a slow byzantine nightmare too (probably the case here).

[blattimwind]

Usually you don't test a single change before merging, but branch from master, merge any number of changes and then run the tests. So the master branch would move forward every 20-30 hours in this case, unless the tests of a merge batch fail, in which case master would kinda stall for a bit.