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).

flake8:
    image: octobus/ci-py2-hgext3rd
    script:
        - hg files -0 'set:(**.py or grep("^#!.*python")) - removed()' -X hgext3rd/evolve/thirdparty | xargs -0 flake8

tests-py2-cext:
    image: octobus/ci-py2-hgext3rd
    script:
        - hg pull -R /ci/repos/mercurial/
        - hg_rev=$(tests/testlib/map-hg-rev.sh "$(hg log -r . -T '{branch}')")
        - hg -R /ci/repos/mercurial/ update "$hg_rev"
        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)

tests-py2-pure:
    image: octobus/ci-py2-hgext3rd
    script:
        - hg pull -R /ci/repos/mercurial/
        - hg_rev=$(tests/testlib/map-hg-rev.sh "$(hg log -r . -T '{branch}')")
        - hg -R /ci/repos/mercurial/ update "$hg_rev"
        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always --pure)

tests-py3-cext:
    image: octobus/ci-py3-hgext3rd
    script:
        - hg pull -R /ci/repos/mercurial/
        - hg_rev=$(tests/testlib/map-hg-rev.sh "$(hg log -r . -T '{branch}')")
        - hg -R /ci/repos/mercurial/ update "$hg_rev"
        - (cd tests; python3 /ci/repos/mercurial/tests/run-tests.py --color=always)

tests-py3-pure:
    image: octobus/ci-py3-hgext3rd
    script:
        - hg pull -R /ci/repos/mercurial/
        - hg_rev=$(tests/testlib/map-hg-rev.sh "$(hg log -r . -T '{branch}')")
        - hg -R /ci/repos/mercurial/ update "$hg_rev"
        - (cd tests; python3 /ci/repos/mercurial/tests/run-tests.py --color=always --pure)

doc:
    image: octobus/ci-py2-evolve-doc
    script:
        - cd docs/
        - make
    variables:
        LANG: en_us.UTF-8
    artifacts:
        paths:
            - html/*