Re: [PATCH] [GSOC][RFC] format-patch: pass --right-only to range-diff

>
> On Sun, Mar 07, 2021 at 06:57:19AM +0000, ZheNing Hu via GitGitGadget wrote:
> > From: ZheNing Hu <adlternative@gmail.com>
> >
> > In https://lore.kernel.org/git/YBx5rmVsg1LJhSKN@nand.local/,
> > Taylor Blau proposing 'git format-patch --cover-letter
> > --range-diff' may mistakenly place upstream commit in the
> > range-diff output. Teach `format-patch` pass `--right-only`
> > to range-diff, maybe can avoid this kind of mistake.
> >
> > Because `git rebase --apply` will internally call `git
> > format-patch -k --stdout --full-index --cherry-pick --right-only
> > --src-prefix=a/ --dst-prefix=b/ --no-renames --no-cover-letter
> > --pretty=mboxrd --topo-order --no-base`, In order to avoid the
> > ambiguity of `--right-only`, users can call `format-patch
> > --range-diff --only-right` instead of `--right-only` to only emit
> > output related to the second range.
>
> A couple of times this new option is called "--right-only" and other
> times it is "--only-right". This comment makes me think that you meant
> to call it "--only-right", but...
>
> > Signed-off-by: ZheNing Hu <adlternative@gmail.com>
> > ---
> >     [GSOC][RFC] format-patch: pass --right-only to range-diff
> >
> >     Transfer parameters are relatively simple. But because I can' t
> >     reproduce the situation, There's no big difference between adding
> >     ---only-right and not adding ---only-right. So I haven't written the
> >     test files for the time being.
>
> Note that I think (and Johannes--cc'd--could confirm) that what you want
> is '--left-only' to discard rebased changes from the upstream branch:
>
> In either case, this should help you reproduce it (and would be a good
> starting point for adding a test case). Here, we're using '--left-only'
> to discard changes from upstream (here, the 'main' branch) after
> rebasing:
>
>     #!/bin/sh
>
>     set -e
>
>     rm -fr repo
>     git init repo
>     cd repo
>
>     git branch -M main
>
>     echo "base" >base
>     git add base
>     git commit -m "base"
>
>     git checkout -b my-feature
>     echo "feature" >feature
>     git add feature
>     git commit -m "feature"
>
>     base="$(git rev-parse main)"
>     old="$(git rev-parse my-feature)"
>
>     git checkout main
>     echo "other" >>base
>     git add base
>     git commit -m "new"
>
>     git checkout my-feature
>     git rebase $base --onto main
>
>     tip="$(git rev-parse my-feature)"
>
>     git range-diff $base $old $tip
>     git range-diff --left-only $base $old $tip
>

> >     I may need to ask reviewers opinion first.
> >
> >     this want to fix #876 Thanks.
> >
> > Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-898%2Fadlternative%2Fformat-patch-range-diff-right-only-v1
> > Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-898/adlternative/format-patch-range-diff-right-only-v1
> > Pull-Request: https://github.com/gitgitgadget/git/pull/898
> >
> >  Documentation/git-format-patch.txt |  5 ++++-
> >  builtin/log.c                      | 15 ++++++++++-----
> >  2 files changed, 14 insertions(+), 6 deletions(-)
> >
> > diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
> > index 3e49bf221087..5dae34c3090b 100644
> > --- a/Documentation/git-format-patch.txt
> > +++ b/Documentation/git-format-patch.txt
> > @@ -27,7 +27,7 @@ SYNOPSIS
> >                  [--[no-]encode-email-headers]
> >                  [--no-notes | --notes[=<ref>]]
> >                  [--interdiff=<previous>]
> > -                [--range-diff=<previous> [--creation-factor=<percent>]]
> > +                [--range-diff=<previous> [--creation-factor=<percent>] [--right-only]]
> >                  [--filename-max-length=<n>]
> >                  [--progress]
> >                  [<common diff options>]
> > @@ -301,6 +301,9 @@ material (this may change in the future).
> >       creation/deletion cost fudge factor. See linkgit:git-range-diff[1])
> >       for details.
> >
> > +--only-right:
> > +     Used with `--range-diff`, only emit output related to the second range.
> > +
>
> s/--only-right/--right-only?

>
> >  --notes[=<ref>]::
> >  --no-notes::
> >       Append the notes (see linkgit:git-notes[1]) for the commit
> > diff --git a/builtin/log.c b/builtin/log.c
> > index f67b67d80ed1..5d2f39fd19a7 100644
> > --- a/builtin/log.c
> > +++ b/builtin/log.c
> > @@ -1153,7 +1153,7 @@ static void make_cover_letter(struct rev_info *rev, int use_separate_file,
> >                             struct commit *origin,
> >                             int nr, struct commit **list,
> >                             const char *branch_name,
> > -                           int quiet)
> > +                           int quiet, int right_only)
> >  {
> >       const char *committer;
> >       struct shortlog log;
> > @@ -1228,7 +1228,8 @@ static void make_cover_letter(struct rev_info *rev, int use_separate_file,
> >                       .creation_factor = rev->creation_factor,
> >                       .dual_color = 1,
> >                       .diffopt = &opts,
> > -                     .other_arg = &other_arg
> > +                     .other_arg = &other_arg,
> > +                     .right_only = right_only
> >               };
> >
> >               diff_setup(&opts);
> > @@ -1732,7 +1733,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
> >       struct strbuf rdiff2 = STRBUF_INIT;
> >       struct strbuf rdiff_title = STRBUF_INIT;
> >       int creation_factor = -1;
> > -
> > +     int right_only = 0;
>
> Nit: the newline between creation_factor's declaration and
> builtin_format_patch_options's is good to keep.
>
> >       const struct option builtin_format_patch_options[] = {
> >               OPT_CALLBACK_F('n', "numbered", &numbered, NULL,
> >                           N_("use [PATCH n/m] even with a single patch"),
> > @@ -1814,6 +1815,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
> >                            parse_opt_object_name),
> >               OPT_STRING(0, "range-diff", &rdiff_prev, N_("refspec"),
> >                          N_("show changes against <refspec> in cover letter or single patch")),
> > +             OPT_BOOL(0, "only-right", &right_only,
> > +                      N_("only emit output related to the second range")),
> >               OPT_INTEGER(0, "creation-factor", &creation_factor,
> >                           N_("percentage by which creation is weighted")),
> >               OPT_END()
> > @@ -2087,7 +2090,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
> >               creation_factor = RANGE_DIFF_CREATION_FACTOR_DEFAULT;
> >       else if (!rdiff_prev)
> >               die(_("--creation-factor requires --range-diff"));
> > -
> > +     if (right_only && !rdiff_prev)
> > +             die(_("--right_only requires --range-diff"));
>
> These may be good to combine into one big conditional that dies whenever
> an option requiring --range-diff is set, but --range-diff is not:
>

>   if (!rdiff_prev) {
>     if (creation_factor)
>       die(_("--creation-factor requires --range-diff"));
>     if (right_only)
>       die(_("--right-only requires --range-diff"));
>   }
>
> Thanks,
> Taylor