Try rerunning the solver with --reorder-goals when it reaches the backjump limit.

[sebright]

This idea is from #1780 (comment). It is a way to find solutions to more dependency problems in a reasonable amount of time without enabling --reorder-goals by default. --reorder-goals sometimes finds solutions to complex dependency problems more quickly, though it usually slows down simple cases.

cabal could first run the solver without --reorder-goals, but with a backjump limit. If the first run reached the backjump limit, it could run the solver again, with --reorder-goals and a similar backjump limit. This strategy could avoid slowing down the solver in easy cases where the first run finds a solution.

[sebright]

#7784 shows that --reorder-goals can cause major slowdown for each step of dependency solving, which means that limiting the number of backjumps wouldn't be enough to limit runtime during the phase when --reorder-goals is enabled. We shouldn't implement this feature without a better way to limit runtime.