Rounding error in A*

[vpaturet]

Some trip searches trigger the following warning in the logs:

A graph path arrives after the requested time. This implies a bug

Debugging a few occurrences of this bug shows that the difference between arrival time and requested time is always 1s.

It seems this is a side-effect of #6436

Version of OTP used (exact commit hash or JAR name)

Latest dev-2x

Data sets in use (links to GTFS and OSM PBF files)

Norwegian dataset.

[tkalvas]

I spent most of the time on 6436 on trying to keep the times equal when changing direction, but apparently there is still at least one case where the rounding is different. Others have reported the issue too.

What I'd like to do is put code to dump the entire path to the error log when that happens, but people might dislike the impact on logging volume. I don't think it is a very common bug though.

[tkalvas]

Anyway, GraphPathFinder.java:142 Instant reqTime = request.dateTime().truncatedTo(ChronoUnit.SECONDS); is just wrong. The truncation of the instant does not happen in the search, so it should not happen here either.

[tkalvas]

Ok I have a unit test, I'm on it.

[tkalvas]

Almost fixed in #6484 , working on it.

[tkalvas]

Ok, it's harder than I thought. I'll come back to this on Wednesday at the earliest.

[tkalvas]

I'm pretty sure now that the only problem was the incorrect truncate, which led to the check being wrong.

Fixed in #6484

[tkalvas]

I'm starting to believe I want to force the input to be an integer number of seconds. I'm not sure that's enforced at the present, I will check. The alternative is to make everything millisecond-based and get rid of the roundings.