"Phillip Wood via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes:
> From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
>
> As --keep-base does not rebase the branch it is confusing if it
> removes commits that have been cherry-picked to the upstream branch.
> As --reapply-cherry-picks is not supported by the "apply" backend this
> commit ensures that cherry-picks are reapplied by forcing the upstream
> commit to match the onto commit unless --no-reapply-cherry-picks is
> given.
>
> Reported-by: Philippe Blain <levraiphilippeblain@xxxxxxxxx>
> Signed-off-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
> ---
> Documentation/git-rebase.txt | 2 +-
> builtin/rebase.c | 15 ++++++++++++++-
> t/t3416-rebase-onto-threedots.sh | 21 +++++++++++++++++++++
> 3 files changed, 36 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> index 080658c8710..dc0c6c54e27 100644
> --- a/Documentation/git-rebase.txt
> +++ b/Documentation/git-rebase.txt
> @@ -218,7 +218,7 @@ leave out at most one of A and B, in which case it defaults to HEAD.
> merge base of `<upstream>` and `<branch>`. Running
> `git rebase --keep-base <upstream> <branch>` is equivalent to
> running
> - `git rebase --onto <upstream>...<branch> <upstream> <branch>`.
> + `git rebase --reapply-cherry-picks --onto <upstream>...<branch> <upstream> <branch>`.
> +
> This option is useful in the case where one is developing a feature on
> top of an upstream branch. While the feature is being worked on, the
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 86ea731ca3a..b6b3e00e3b1 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -1181,6 +1181,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> prepare_repo_settings(the_repository);
> the_repository->settings.command_requires_full_index = 0;
>
> + options.reapply_cherry_picks = -1;
> options.allow_empty_message = 1;
> git_config(rebase_config, &options);
> /* options.gpg_sign_opt will be either "-S" or NULL */
> @@ -1240,6 +1241,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> if (options.root)
> die(_("options '%s' and '%s' cannot be used together"), "--keep-base", "--root");
> }
> + /*
> + * --keep-base defaults to --reapply-cherry-picks as it is confusing if
> + * commits disappear when using this option.
> + */
> + if (options.reapply_cherry_picks < 0)
> + options.reapply_cherry_picks = keep_base;
It makes me wonder if an explicit "--no-reapply-cherry-picks" makes
sense in combination with "--keep-base". If that happens, we do not
take this "By default, reapply is enabled with keep-base".
> @@ -1416,7 +1423,11 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> if (options.empty != EMPTY_UNSPECIFIED)
> imply_merge(&options, "--empty");
>
> - if (options.reapply_cherry_picks)
> + /*
> + * --keep-base implements --reapply-cherry-picks by altering upstream so
> + * it works with both backends.
> + */
> + if (options.reapply_cherry_picks && !keep_base)
> imply_merge(&options, "--reapply-cherry-picks");
Interesting. The idea is that we shouldn't care how much progress
(which may include cherry-picks) the upstream side made, and it is
no use to compare the commits between the F (fork point) and O (our
tip) against the commits between updated U (upstream) and F (fork
point) to notice that X' is a cherry-pick from our X.
o---X---o---O (our work)
/
----F----o----o----o----X'----U (upstream)
So almost ignoring U (except for obviously figure out F, possibly,
for the purpose of keep-base) is an effective way to keep X on our
history, and when it happens, we do not have to explicitly pass the
"--reapply" option to underlying rebase machinery. Makes sense.
If an explicit "--no-reapply-cherry-picks" with "--keep-base" is
given, we still skip this and do not call imply_merge() ...
> @@ -1680,6 +1691,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> }
> if (keep_base) {
> oidcpy(&merge_base, &options.onto->object.oid);
> + if (options.reapply_cherry_picks)
> + options.upstream = options.onto;
... but this is also skipped in such a case. I do not offhand know
if the combination makes practical sense, but this should allow the
combination to "work". OK.
Thanks.
