Johannes Schindelin <johannes.schinde...@gmx.de> writes:
> Junio, I think this is now ready for `next`. Thank you for your patience > and help with this. > > Once upon a time, I dreamed of an interactive rebase that would not > linearize all patches and drop all merge commits, but instead recreate > the commit topology faithfully. > > My original attempt was --preserve-merges, but that design was so > limited that I did not even enable it in interactive mode. > > Subsequently, it *was* enabled in interactive mode, with the predictable > consequences: as the --preserve-merges design does not allow for > specifying the parents of merge commits explicitly, all the new commits' > parents are defined *implicitly* by the previous commit history, and > hence it is *not possible to even reorder commits*. > > This design flaw cannot be fixed. Not without a complete re-design, at > least. This patch series offers such a re-design. > > Think of --rebase-merges as "--preserve-merges done right". It > introduces new verbs for the todo list, `label`, `reset` and `merge`. > For a commit topology like this: > > A - B - C > \ / > D > > the generated todo list would look like this: > > # branch D > pick 0123 A > label branch-point > pick 1234 D > label D > > reset branch-point > pick 2345 B > merge -C 3456 D # C > > There are more patches in the pipeline, based on this patch series, but > left for later in the interest of reviewable patch series: one mini > series to use the sequencer even for `git rebase -i --root`, and another > one to add support for octopus merges to --rebase-merges. And then one > to allow for rebasing merge commits in a smarter way (this one will need > a bit more work, though, as it can result in very complicated, nested > merge conflicts *very* easily). > > Changes since v8: > > - Disentangled the patch introducing `label`/`reset` from the one > introducing `merge` again (this was one stupid, tired `git commit > --amend` too many). > > - Augmented the commit message of "introduce the `merge` command" to > describe what the `label onto` is all about. > > - Fixed the error message when `reset` would overwrite untracked files to > actually say that a "reset" failed (not a "merge"). > > - Clarified the rationale for `label onto` in the commit message of > "rebase-helper --make-script: introduce a flag to rebase merges". > > - Edited the description of `--rebase-merges` heavily, for clarity, in > "rebase: introduce the --rebase-merges option". > > - Edited the commit message of (and the documentation introduced by) " rebase > -i: introduce --rebase-merges=[no-]rebase-cousins" for clarity (also > mentioning the `--ancestry-path` option). > > - When run_git_commit() fails after a successful merge, we now take pains > not to reschedule the `merge` command. > > - Rebased the patch series on top of current `master`, i.e. both > `pw/rebase-keep-empty-fixes` and `pw/rebase-signoff`, to resolve merge > conflicts myself. > > > Johannes Schindelin (15): > sequencer: avoid using errno clobbered by rollback_lock_file() > sequencer: make rearrange_squash() a bit more obvious > sequencer: refactor how original todo list lines are accessed > sequencer: offer helpful advice when a command was rescheduled > sequencer: introduce new commands to reset the revision > sequencer: introduce the `merge` command > sequencer: fast-forward `merge` commands, if possible > rebase-helper --make-script: introduce a flag to rebase merges > rebase: introduce the --rebase-merges option > sequencer: make refs generated by the `label` command worktree-local > sequencer: handle post-rewrite for merge commands > rebase --rebase-merges: avoid "empty merges" > pull: accept --rebase=merges to recreate the branch topology > rebase -i: introduce --rebase-merges=[no-]rebase-cousins > rebase -i --rebase-merges: add a section to the man page > > Phillip Wood (1): > rebase --rebase-merges: add test for --keep-empty > > Stefan Beller (1): > git-rebase--interactive: clarify arguments > > Documentation/config.txt | 8 + > Documentation/git-pull.txt | 6 +- > Documentation/git-rebase.txt | 163 ++++- > builtin/pull.c | 14 +- > builtin/rebase--helper.c | 13 +- > builtin/remote.c | 18 +- > contrib/completion/git-completion.bash | 4 +- > git-rebase--interactive.sh | 22 +- > git-rebase.sh | 16 + > refs.c | 3 +- > sequencer.c | 892 ++++++++++++++++++++++++- > sequencer.h | 7 + > t/t3421-rebase-topology-linear.sh | 1 + > t/t3430-rebase-merges.sh | 244 +++++++ > 14 files changed, 1352 insertions(+), 59 deletions(-) > create mode 100755 t/t3430-rebase-merges.sh > > > base-commit: 1f1cddd558b54bb0ce19c8ace353fd07b758510d > Published-As: https://github.com/dscho/git/releases/tag/recreate-merges-v9 > Fetch-It-Via: git fetch https://github.com/dscho/git recreate-merges-v9 > > Interdiff vs v8: > diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt > index e691b93e920..bd5ecff980e 100644 > --- a/Documentation/git-rebase.txt > +++ b/Documentation/git-rebase.txt > @@ -381,21 +381,24 @@ have the long commit hash prepended to the format. > > -r:: > --rebase-merges[=(rebase-cousins|no-rebase-cousins)]:: > - By default, a rebase will simply drop merge commits and only rebase > - the non-merge commits. With this option, it will try to preserve > + By default, a rebase will simply drop merge commits from the todo > + list, and put the rebased commits into a single, linear branch. > + With `--rebase-merges`, the rebase will instead try to preserve > the branching structure within the commits that are to be rebased, > - by recreating the merge commits. If a merge commit resolved any merge > - or contained manual amendments, then they will have to be re-applied > - manually. > + by recreating the merge commits. Any resolved merge conflicts or > + manual amendments in these merge commits will have to be > + resolved/re-applied manually. > + > By default, or when `no-rebase-cousins` was specified, commits which do not > -have `<upstream>` as direct ancestor will keep their original branch point. > -If the `rebase-cousins` mode is turned on, such commits are instead rebased > +have `<upstream>` as direct ancestor will keep their original branch point, > +i.e. commits that would be excluded by gitlink:git-log[1]'s > +`--ancestry-path` option will keep their original ancestry by default. If > +the `rebase-cousins` mode is turned on, such commits are instead rebased > onto `<upstream>` (or `<onto>`, if specified). > + > -This mode is similar in spirit to `--preserve-merges`, but in contrast to > -that option works well in interactive rebases: commits can be reordered, > -inserted and dropped at will. > +The `--rebase-merges` mode is similar in spirit to `--preserve-merges`, but > +in contrast to that option works well in interactive rebases: commits can be > +reordered, inserted and dropped at will. > + > It is currently only possible to recreate the merge commits using the > `recursive` merge strategy; Different merge strategies can be used only via > diff --git a/sequencer.c b/sequencer.c > index b5715f69450..e2f83942843 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -2635,6 +2635,7 @@ static int do_reset(const char *name, int len, struct > replay_opts *opts) > } > > memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts)); > + setup_unpack_trees_porcelain(&unpack_tree_opts, "reset"); > unpack_tree_opts.head_idx = 1; > unpack_tree_opts.src_index = &the_index; > unpack_tree_opts.dst_index = &the_index; > @@ -2855,7 +2856,12 @@ static int do_merge(struct commit *commit, const char > *arg, int arg_len, > if (ret) > rerere(opts->allow_rerere_auto); > else > - ret = run_git_commit(git_path_merge_msg(), opts, > + /* > + * In case of problems, we now want to return a positive > + * value (a negative one would indicate that the `merge` > + * command needs to be rescheduled). > + */ > + ret = !!run_git_commit(git_path_merge_msg(), opts, > run_commit_flags); > > leave_merge: > @@ -3809,12 +3815,9 @@ int sequencer_make_script(FILE *out, int argc, const > char **argv, > > init_revisions(&revs, NULL); > revs.verbose_header = 1; > - if (rebase_merges) > - revs.cherry_mark = 1; > - else { > + if (!rebase_merges) > revs.max_parents = 1; > - revs.cherry_pick = 1; > - } > + revs.cherry_mark = 1; > revs.limited = 1; > revs.reverse = 1; > revs.right_only = 1;
