> When we Wait() on the errgroup, it will cancel its context even when every spawned go routine has returned nil.

I wonder why. It's documented [1] but seems strange to me. It enforces that errgroup is single-use (rather than cyclical), but I might do that by outright panicking if Go is called after Wait returns. Goroutines in the group might launch others in the group, but presumably not after they've finished, so I'd expect after Wait returns that there are no more calls to Go. Unless folks are passing the group to existing goroutines and then those launch more tasks in the group? That seems like an undesirable pattern.

[1] though not on Wait, just on WithContext: https://pkg.go.dev/golang.org/x/sync/errgroup#WithContext