On Mon, May 28, 2018 at 1:48 PM, Elijah Newren <newren@xxxxxxxxx> wrote: > Hi everyone, > > I have some merge-related plans (and work in progress) that I'd like > to get some feedback on in order to find what order would be best to > address things in, if there are special steps I should take while > approaching some of the bigger items, and even if folks disagree with > any of the plans. > > > Currently, I would like to: > > A) Fix cases where directory rename detection does not work with > rebase/am due to how they call merge-recursive. > > Notes: Could just wait for D & E to land before fixing. > Alternatively, email RFC to list now explaining issues and how the > fix has performance implications; poll for opinions on whether to > fix before or after D. > > B) Implement a remerge-diff ability (compare a merge commit to what an > "automatic merge" would look like)[1]. > > Notes: Possibly for cherry-picks and reverts too. Depends on C & > E. > > C) Modify/extend how path-based and mode-based conflicts are > communicated to the user. > > Notes: Particularly important as a mechanism for handling > challenges[2] with implementing the remerge-diff ability. Need to > send RFC to list with ideas to get feedback. > > D) Improve merge performance. > > Notes: Includes 4-5 specific optimizations[5], some of which I > expect to be somewhat invasive and thus may make more sense to just > make part of the new merge strategy implemented in E. Biggest > optimization depends on F. > > E) Write a new merge strategy meant to replace merge-recursive. > > Notes: Suggested by Junio[3][4]. Depends on F & G. > > F) Make file collision conflict types more consistent. > > Notes: Specifically, make rename/rename(2to1) & rename/add > conflicts behave more like add/add[6][7]. Depends on part of G. > Would prefer H to be accepted first. > > G) Improve merge-related portion of testsuite. > > Notes: Intended to help test new merge strategy with more > confidence. Will include approximately a dozen edge and corner > cases where merge-recursive currently falls short. Started at [8]; > see also [9]. Most items forward-reference "Depends on (<later letter>) up to here; (H) seems independent, but might be a good first start. (G) [8] is queued as origin/en/merge-recursive-tests, or do you mean to expand (G) into a mini-framework of merge-testing? i.e. run the mini test framework multiple times, each using a different merge strategy, similar to submodule tests, e.g. see t/lib-submodule-update.sh and one of its users, t1013. > H) Miscellaneous code cleanups irritating me while working on other > changes[10]. > > > My current plan was to work roughly in reverse, from H to A. Some questions: > > * Does any of this look objectionable? Going in order A-H seems slightly out-of-order to me, I'd think (H) and (G) would go first; (B) sounds like an independent feature, which could go in parallel? > * Should I post RFC questions on A and C earlier? I would think so, it is easier to give feedback on code, I would think. > * Should I split D and G? (Current plan was to keep D together, but > split G into five short slightly inter-dependent topics) I would have expected to have tests (G) as a companion of (A) or (C) rather than (D), as performance improvements would keep the test suite unchanged? > * E is kind of big. Are there any specific things folks would like to see > with how that is handled? How much abstraction can be done ahead of time such that there is an interface/API where you just plug in a new merge strategy and do not need to duplicate a lot of code/tests? Stefan
