fixup for cycle detection

[schveiguy]

Adds new "deprecate" mode for cycle handling: if cycle is detected, runs original flawed algorithm. If that algorithm finds no cycle, continue execution of the program with old sorted order, but print a deprecation warning to stderr.

Still needs doc update. Ping @MartinNowak

[dlang-bot]

Fix	Bugzilla	Description
✗	16211	[REG 2.058] Cyclic dependencies broken again

[schveiguy]

Ping @Dicebot @CyberShadow

[mihails-strasuns]

Thanks a lot! Will test later today.

[MartinNowak]

Seems correct but slightly unrelated (though you prolly double checked for the old implementation).
That means we could change the type of edges to uint, right?

[schveiguy]

Yes, I realized this was a remnant from the implementation that still used the findModule function. I don't put cross-module dependencies as -1 in the edges array, so no point in checking for -1 here.

[schveiguy]

That means we could change the type of edges to uint, right?

Hm... probably could. I don't think it's too important though, no chance of having over 2 billion modules to sort. I'm leery of unsigned math, too.

[MartinNowak]

Thanks, fixes Higgs and vibe-d/libasync.

[schveiguy]

fixes Higgs and vibe-d/libasync

curious, I'm assuming you get the deprecation printout?

[mihails-strasuns]

Just got to test it, work like a charm:

Deprecation 16211 warning:
A cycle has been detected in your program that was undetected prior to DMD
2.072. This program will continue, but will not operate when using DMD 2.073
to compile. Use runtime option --DRT-oncycle=print to see the cycle details.