Recurring task stops spawning children in case frequency is reduced

[languitar]

I have a recurring task that exists since years. Once I reduced the frequency of the recurrence rule, no new children are spawned. This is the log of the parent: https://gist.github.com/languitar/62e5821419a51d63c3c403518417c513

Suspicion on IRC was that the expected amount of mask symbols isn't updated.

[pbeckingham]

The recurrent was changed (see line 92), which effectively should have halved the length of the mask value, but it was not changed. This means that there would be something like 16 additional child tasks that it would not generate until reality length caught up with the mask length.

The solution is to identify when the recurrent is being modified, and regenerate an appropriate mask.

[djmitche]

@carmiac has proposed a major revision to recurrence support in https://github.com/carmiac/taskchampion/blob/798cec2b40f13c420ef6358e4d99b251e58249de/docs/src/iterative-tasks.md. If you're following this issue, please have a look and comment in GothenburgBitFactory/taskchampion#729.