evolve: refactor the code which swap two nodes (in divergence resolution) I see that we are using the code to swap the "divergent" and "other" node; and updating the evolvestate accordingly at many places in divergence resolution. This patch extract that code to a function. Although I don't have strong opinion on this patch. It's a volunteered patch to remove some redundancy.

evolve: remove tmpctx arg from _resolvephasedivergent() Before this patch, in _resolvephasedivergent() function we were passing an optional argument "tmpctx" which was used to store a rebased version of bumped if required. But for sake of simplicity we can achieve the same results even without passing this "tmpctx" into that function. No changes in test files demonstrate that this patch don't break anything.

doc: clarify _resolvephasedivergent role and constraint Small documentation patch before larger changes.