Make debug flag manual

[phadej]

By default flags are automatic. The debug flag is intended to be enabled manually, it seems bizarre to allow solvers to flip it.

[konsumlamm]

So actually this makes the debug flag manual (and not automatic, as the title/commit says).

[phadej]

So actually this makes the debug flag manual (and not automatic, as the title/commit says).

Yes

[phadej]

ping

[treeowl]

Who's being pinged?

[phadej]

Maintainers of unordered-containers.

[treeowl]

This seems reasonable on its surface, but I don't know enough about cabal. So a couple quick questions before I merge:

1. How could it be flipped automatically?
2. Why do we want to forbid automatic flipping? Is that a performance issue? A correctness issue?

[phadej]

How could it be flipped automatically?

By a solver.

Why do we want to forbid automatic flipping?

Because the flip to debug may happen unattendedly. debug has performance implications.

[treeowl]

How could it be flipped automatically?

By a solver.

Would you mind expanding on this just a little for my own education? What is a solver, exactly, and how would I end up with one that flips debug flags?

[phadej]

What is a solver, exactly, and how would I end up with one that flips debug flags?

Dependency solver. You may not, some other people may.

But I'm not keen on pushing this through anymore. May the solver flip flags on its will.