evolve: add test to show that user can create phase-divergence locally After resolution of phase-divergence, user can locally create phase-divergence by rewriting the old bumped (obsolete now) changeset. Next patch will be adding the pre-check logic for creation of this phase-divergence.

evolve: remove unnecessary code since it's been covered already We don't need this logic any more since the case of "two divergent csets where one is the parent of other" has been handled correctly by the logic present in method _prepcontentdivresolution() This is how things works in method _prepcontentdivresolution() for our case i.e "content-divergence with parent-child relation": cset_b (content-divergent) | cset_a (content-divergent) | ~ Acc. to revision selection criteria: "divergent" = min_revision(cset_a, cset_b) So always "divergent" will be cset_a and "other" will be "cset_b" and resolution parent will be the successor of parent of cset_a Both the csets will be merged and resolution cset will be based on correct revision. The result could be wrong only in the case when "divergent" is cset_b which is not possible acc. to the current logic.

test: no need to look at full log

evolve: refactor content-divergence resolution logic > What is the case we are looking at? This is about refactoring the part of content-div resolution logic where it decides which cset should be relocated and where. > What is a "topologicial common ancestors" vs a "greatest common ancestors"? `tca` is an ancestor which we can decide/find by looking at the at graph visually for e.g ``` c3(*) c4(*) | | c2(x) c1(x) c5 | / \ | / c0 ``` (c5 is the successor of c2 and c1) now here, `tca` of c3 and c4 is: c0 `gca` of c3 and c4 is: c5 > What is the new top-level logic/behavior that makes it better? The old code had some unnecessary edge cases just because we were using `gca`, since it can point to a revision that is not a topological ancestor. For e.g see b779b40f996e Eventually, the code around this was getting messy unnecessarily. So I looked into it and found a simple and more robust approach. And in new code, it is simple and straightforward (and easy to understand), where we handle the following 4 cases when solving content-div: 1) when both are on the same parent => (no need to do anything special, and simply proceed) 2) both are on the different parent but a) `tca` is the parent of one of them or b) there is no non-obsolete revision between `tca` and one of the divergent cset. => (relocate one to the other side and proceed) 3) both are on different parents and `tca` is not the parent of any of them and there is at least one non-obsolete cset between tca and both the divergent cset i.e (tca::div1) and (tca::div2) both the ranges have at least one non-obs revision. => (this is the case which we don't handle yet, but the solution would be to prompt the user to choose an evolve destination.) 4) both are in the parent-child relation => (both are merged and new cset will be based on the successor of `tca`) Changes in test-evolve-issue5958.t demonstrate that new code also covered case4 because in a resolution of "two divergent csets with parent-child relation" there should be one cset as a result and no orphan revs (as you can see there was an orphan before this patch).

evolve: remove duplicated code See at line 500.

evolve: make necessary changes in a test to reflect a fix in next patch

evolve: add quotes around the action in msg of pre-checking