Public Access
jaap-jan
25407756c3
The first pass of the update loop waited two minutes. Every pass after it came six hours apart, which is the right interval for a product that ships rarely — but the delay in front of the first one quietly excluded a whole way of using this application. A client opened to reach one host and closed again is over before the two minutes are. Used that way, it never checks at all: not once, not slowly, never. That is precisely the machine ADR 0011 names as the real cost of distributing outside a store — quietly a year behind — and the galling part is that the mechanism to fix it was switched on the whole time and simply never reached. The delay's own argument is recorded in the diff it is being removed from, and it was not a bad one: nothing anybody does in their first two minutes depends on an update, and launch is already contending for the network with a schema migration, a resumed sign-in and a first sync, at the one moment somebody is watching the window. What it weighed was the cost of checking early against the benefit of checking early. It never weighed the cost of not checking at all. ◆ THE YIELD IS WHAT KEEPS THIS OFF THE LAUNCH PATH, AND IT IS NOT DECORATION. Start() is called from MainWindowViewModel.StartAsync ahead of the migration, so an inline first pass would run whatever the channel does before its own first await — Velopack reads the install layout from disk — between the user and their window. Yielding hands the rest of launch back and puts the check in a later turn, which is the same moment in every sense anybody can perceive and none of the cost. So the answer to the delay's argument is not that it was wrong; it is that a yield buys most of what two minutes bought. Task.Yield takes no token where Task.Delay did, so the loop body now observes cancellation at its head. Without that, an application closed during launch spends its last moment asking a release channel about a build it will not run. Two things deliberately not changed. The AUTOMATIC UPDATE CHECKS preference still gates the pass — "on start" means every start, not regardless of what the user asked for, and that setting is already on by default. And the data cost is unchanged rather than merely acceptable: a check is a few hundred bytes and the download only follows if something newer exists, so this moves the same traffic earlier without adding any. That matters most on the phone, where the same loop runs against AndroidUpdateChannel. TheFirstPassRunsAtStart_RatherThanOnADelay drives the real loop rather than CheckOnceAsync, which is the one thing that file otherwise avoids — and here it is the point, because the claim is about when the pass happens rather than what it does. It waits on the pass and not on a clock, so there is nothing to be flaky about: a regression that puts a delay back does not fail on a margin, it spins until the suite's own cancellation ends it. DisposingStopsTheLoop keeps its assertion and gains a note that it is now a race rather than a formality. §16.7 of the manual checks gains the sentence that reopening the application does what CHECK NOW does. It is the step somebody following that section would otherwise discover by accident. 447 App tests and 153 layout tests pass.