Fix: IntensityTracker properly returns error when limit is exceeded

[kodumbeats]

Summary: The IntensityTracker does not short-circuit due to a logic bug in recursion.

Expected behavior: If I set a limit of 5 restarts per minute, I expect six restarts to throw the error TooIntense

Actual behavior: The error does not throw, no matter how many times the supervisor restarts a child.

Explanation:

On the first event sent to the intensity_tracker:

now == event

So the subsequent logical check into recursion:

now >= event + period

always evaluated False given the default restart period. The event was always stripped from internal state, so the intensity_tracker never held more than one event at a time. The code in question:

otp/src/gleam/otp/intensity_tracker.gleam

Lines 26 to 35 in 45deedf

	pub fn trim_window(events: List(Int), now: Int, period: Int) -> List(Int) {
	case events {
	[] -> []
	[event, ..events] ->
	case now >= event + period {
	True -> [event, ..trim_window(events, now, period)]
	False -> []
	}
	}
	}

This patch also includes tests for expected behavior. When testing, I discovered event maximum limit check was off by one, so this patch corrects and tests that edge case.

This was one of those pull-your-hair-out kind of bugs 🐛 Happy to make any changes!

[lpil]

Thank you!!