Re: [PATCH v2 2/5] rebase -i: support --committer-date-is-author-date

[Elijah Newren <newren@gmail.com>]

On Wed, Apr 29, 2020 at 3:26 AM Phillip Wood <phillip.wood123@gmail.com> wrote:
>
> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> As part of the on-going effort to retire the apply rebase backend teach
> the merge backend how to handle --committer-date-is-author-date.
>
> Original-patch-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---
>  Documentation/git-rebase.txt           | 10 +++--
>  builtin/rebase.c                       | 16 ++++---
>  sequencer.c                            | 60 +++++++++++++++++++++++++-
>  sequencer.h                            |  1 +
>  t/t3422-rebase-incompatible-options.sh |  1 -
>  t/t3436-rebase-more-options.sh         | 56 ++++++++++++++++++++++++
>  6 files changed, 133 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> index d060c143e6..8c62645b8c 100644
> --- a/Documentation/git-rebase.txt
> +++ b/Documentation/git-rebase.txt
> @@ -438,9 +438,13 @@ when merging.
>  See also INCOMPATIBLE OPTIONS below.
>
>  --committer-date-is-author-date::
> +       Instead of using the current time as the committer date, use
> +       the author date of the commit being rebased as the committer
> +       date. This option implies --force-rebase.
> +
>  --ignore-date::
> -       These flags are passed to 'git am' to easily change the dates
> -       of the rebased commits (see linkgit:git-am[1]).
> +       This flag is passed to 'git am' to change the author date
> +       of each rebased commit (see linkgit:git-am[1]).
>  +
>  See also INCOMPATIBLE OPTIONS below.
>
> @@ -578,7 +582,6 @@ INCOMPATIBLE OPTIONS
>  The following options:
>
>   * --apply
> - * --committer-date-is-author-date
>   * --ignore-date
>   * --whitespace
>   * -C
> @@ -606,6 +609,7 @@ In addition, the following pairs of options are incompatible:
>   * --preserve-merges and --rebase-merges
>   * --preserve-merges and --empty=
>   * --preserve-merges and --ignore-whitespace
> + * --preserve-merges and --committer-date-is-author-date
>   * --keep-base and --onto
>   * --keep-base and --root
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 5d8e117276..357cd6acf3 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -89,6 +89,7 @@ struct rebase_options {
>         int ignore_whitespace;
>         char *gpg_sign_opt;
>         int autostash;
> +       int committer_date_is_author_date;
>         char *cmd;
>         int allow_empty_message;
>         int rebase_merges, rebase_cousins;
> @@ -126,6 +127,8 @@ static struct replay_opts get_replay_opts(const struct rebase_options *opts)
>         replay.quiet = !(opts->flags & REBASE_NO_QUIET);
>         replay.verbose = opts->flags & REBASE_VERBOSE;
>         replay.reschedule_failed_exec = opts->reschedule_failed_exec;
> +       replay.committer_date_is_author_date =
> +                                       opts->committer_date_is_author_date;
>         replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
>         replay.strategy = opts->strategy;
>
> @@ -1003,6 +1006,8 @@ static int run_am(struct rebase_options *opts)
>
>         if (opts->ignore_whitespace)
>                 argv_array_push(&am.args, "--ignore-whitespace");
> +       if (opts->committer_date_is_author_date)
> +               argv_array_push(&opts->git_am_opts, "--committer-date-is-author-date");
>         if (opts->action && !strcmp("continue", opts->action)) {
>                 argv_array_push(&am.args, "--resolved");
>                 argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
> @@ -1507,9 +1512,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
>                 OPT_BOOL(0, "signoff", &options.signoff,
>                          N_("add a Signed-off-by: line to each commit")),
> -               OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
> -                                 &options.git_am_opts, NULL,
> -                                 N_("passed to 'git am'"), PARSE_OPT_NOARG),
> +               OPT_BOOL(0, "committer-date-is-author-date",
> +                        &options.committer_date_is_author_date,
> +                        N_("make committer date match author date")),
>                 OPT_PASSTHRU_ARGV(0, "ignore-date", &options.git_am_opts, NULL,
>                                   N_("passed to 'git am'"), PARSE_OPT_NOARG),
>                 OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
> @@ -1804,11 +1809,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>             options.autosquash) {
>                 allow_preemptive_ff = 0;
>         }
> +       if (options.committer_date_is_author_date)
> +               options.flags |= REBASE_FORCE;
>
>         for (i = 0; i < options.git_am_opts.argc; i++) {
>                 const char *option = options.git_am_opts.argv[i], *p;
> -               if (!strcmp(option, "--committer-date-is-author-date") ||
> -                   !strcmp(option, "--ignore-date") ||
> +               if (!strcmp(option, "--ignore-date") ||
>                     !strcmp(option, "--whitespace=fix") ||
>                     !strcmp(option, "--whitespace=strip"))
>                         allow_preemptive_ff = 0;
> diff --git a/sequencer.c b/sequencer.c
> index 6fd2674632..3bb80d7414 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -149,6 +149,7 @@ static GIT_PATH_FUNC(rebase_path_refs_to_delete, "rebase-merge/refs-to-delete")
>   * command-line.
>   */
>  static GIT_PATH_FUNC(rebase_path_gpg_sign_opt, "rebase-merge/gpg_sign_opt")
> +static GIT_PATH_FUNC(rebase_path_cdate_is_adate, "rebase-merge/cdate_is_adate")
>  static GIT_PATH_FUNC(rebase_path_orig_head, "rebase-merge/orig-head")
>  static GIT_PATH_FUNC(rebase_path_verbose, "rebase-merge/verbose")
>  static GIT_PATH_FUNC(rebase_path_quiet, "rebase-merge/quiet")
> @@ -872,6 +873,22 @@ static char *get_author(const char *message)
>         return NULL;
>  }
>
> +static const char *author_date_from_env_array(const struct argv_array *env)
> +{
> +       int i;
> +       const char *date;
> +
> +       for (i = 0; i < env->argc; i++)
> +               if (skip_prefix(env->argv[i],
> +                               "GIT_AUTHOR_DATE=", &date))
> +                       return date;
> +       /*
> +        * If GIT_AUTHOR_DATE is missing we should have already errored out when
> +        * reading the script
> +        */
> +       BUG("GIT_AUTHOR_DATE missing from author script");
> +}
> +
>  static const char staged_changes_advice[] =
>  N_("you have staged changes in your working tree\n"
>  "If these changes are meant to be squashed into the previous commit, run:\n"
> @@ -938,6 +955,10 @@ static int run_git_commit(struct repository *r,
>                              gpg_opt, gpg_opt);
>         }
>
> +       if (opts->committer_date_is_author_date)
> +               argv_array_pushf(&cmd.env_array, "GIT_COMMITTER_DATE=%s",
> +                                author_date_from_env_array(&cmd.env_array));
> +
>         argv_array_push(&cmd.args, "commit");
>
>         if (!(flags & VERIFY_MSG))
> @@ -1321,7 +1342,6 @@ static int try_to_commit(struct repository *r,
>
>         if (parse_head(r, &current_head))
>                 return -1;
> -
>         if (flags & AMEND_MSG) {
>                 const char *exclude_gpgsig[] = { "gpgsig", "gpgsig-sha256", NULL };
>                 const char *out_enc = get_commit_output_encoding();
> @@ -1349,6 +1369,30 @@ static int try_to_commit(struct repository *r,
>                 commit_list_insert(current_head, &parents);
>         }
>
> +       if (opts->committer_date_is_author_date) {
> +               int len = strlen(author);
> +               struct ident_split ident;
> +               struct strbuf date = STRBUF_INIT;
> +
> +               if (split_ident_line(&ident, author, len) < 0) {
> +                       res = error(_("malformed ident line '%s'"), author);
> +                       goto out;
> +               }
> +               if (!ident.date_begin) {
> +                       res = error(_("corrupted author without date information"));
> +                       goto out;
> +               }
> +
> +               strbuf_addf(&date, "@%.*s %.*s",
> +                           (int)(ident.date_end - ident.date_begin), ident.date_begin,
> +                           (int)(ident.tz_end - ident.tz_begin), ident.tz_begin);
> +               res = setenv("GIT_COMMITTER_DATE", date.buf, 1);
> +               strbuf_release(&date);
> +
> +               if (res)
> +                       goto out;
> +       }
> +
>         if (write_index_as_tree(&tree, r->index, r->index_file, 0, NULL)) {
>                 res = error(_("git write-tree failed to write a tree"));
>                 goto out;
> @@ -2532,6 +2576,11 @@ static int read_populate_opts(struct replay_opts *opts)
>                         opts->signoff = 1;
>                 }
>
> +               if (file_exists(rebase_path_cdate_is_adate())) {
> +                       opts->allow_ff = 0;
> +                       opts->committer_date_is_author_date = 1;
> +               }
> +
>                 if (file_exists(rebase_path_reschedule_failed_exec()))
>                         opts->reschedule_failed_exec = 1;
>
> @@ -2622,6 +2671,8 @@ int write_basic_state(struct replay_opts *opts, const char *head_name,
>                 write_file(rebase_path_drop_redundant_commits(), "%s", "");
>         if (opts->keep_redundant_commits)
>                 write_file(rebase_path_keep_redundant_commits(), "%s", "");
> +       if (opts->committer_date_is_author_date)
> +               write_file(rebase_path_cdate_is_adate(), "%s", "");
>         if (opts->reschedule_failed_exec)
>                 write_file(rebase_path_reschedule_failed_exec(), "%s", "");
>
> @@ -3542,6 +3593,10 @@ static int do_merge(struct repository *r,
>                         goto leave_merge;
>                 }
>
> +               if (opts->committer_date_is_author_date)
> +                       argv_array_pushf(&cmd.env_array, "GIT_COMMITTER_DATE=%s",
> +                                        author_date_from_env_array(&cmd.env_array));
> +
>                 cmd.git_cmd = 1;
>                 argv_array_push(&cmd.args, "merge");
>                 argv_array_push(&cmd.args, "-s");
> @@ -3819,7 +3874,8 @@ static int pick_commits(struct repository *r,
>         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
>         if (opts->allow_ff)
>                 assert(!(opts->signoff || opts->no_commit ||
> -                               opts->record_origin || opts->edit));
> +                               opts->record_origin || opts->edit ||
> +                               opts->committer_date_is_author_date));
>         if (read_and_refresh_cache(r, opts))
>                 return -1;
>
> diff --git a/sequencer.h b/sequencer.h
> index 0bee85093e..4ab94119ae 100644
> --- a/sequencer.h
> +++ b/sequencer.h
> @@ -45,6 +45,7 @@ struct replay_opts {
>         int verbose;
>         int quiet;
>         int reschedule_failed_exec;
> +       int committer_date_is_author_date;
>
>         int mainline;
>
> diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
> index 55ca46786d..c8234062c6 100755
> --- a/t/t3422-rebase-incompatible-options.sh
> +++ b/t/t3422-rebase-incompatible-options.sh
> @@ -61,7 +61,6 @@ test_rebase_am_only () {
>  }
>
>  test_rebase_am_only --whitespace=fix
> -test_rebase_am_only --committer-date-is-author-date
>  test_rebase_am_only -C4
>
>  test_expect_success REBASE_P '--preserve-merges incompatible with --signoff' '
> diff --git a/t/t3436-rebase-more-options.sh b/t/t3436-rebase-more-options.sh
> index fb5e747e86..84b9d5d37f 100755
> --- a/t/t3436-rebase-more-options.sh
> +++ b/t/t3436-rebase-more-options.sh
> @@ -9,6 +9,9 @@ test_description='tests to ensure compatibility between am and interactive backe
>
>  . "$TEST_DIRECTORY"/lib-rebase.sh
>
> +GIT_AUTHOR_DATE="1999-04-02T08:03:20+05:30"
> +export GIT_AUTHOR_DATE
> +
>  # This is a special case in which both am and interactive backends
>  # provide the same output. It was done intentionally because
>  # both the backends fall short of optimal behaviour.
> @@ -28,8 +31,13 @@ test_expect_success 'setup' '
>         EOF
>         git commit -am "update file" &&
>         git tag side &&
> +       test_commit commit1 foo foo1 &&
> +       test_commit commit2 foo foo2 &&
> +       test_commit commit3 foo foo3 &&
>
>         git checkout --orphan master &&
> +       git rm --cached foo &&
> +       rm foo &&
>         sed -e "s/^|//" >file <<-\EOF &&
>         |line 1
>         |        line 2
> @@ -78,6 +86,54 @@ test_expect_success '--ignore-whitespace is remembered when continuing' '
>         test_cmp expect file
>  '
>
> +test_expect_success '--committer-date-is-author-date works with apply backend' '
> +       GIT_AUTHOR_DATE="@1234 +0300" git commit --amend --reset-author &&
> +       git rebase --apply --committer-date-is-author-date HEAD^ &&
> +       git log -1 --pretty="format:%ai" >authortime &&
> +       git log -1 --pretty="format:%ci" >committertime &&
> +       test_cmp authortime committertime
> +'
> +
> +test_expect_success '--committer-date-is-author-date works with merge backend' '
> +       GIT_AUTHOR_DATE="@1234 +0300" git commit --amend --reset-author &&
> +       git rebase -m --committer-date-is-author-date HEAD^ &&
> +       git log -1 --pretty="format:%ai" >authortime &&
> +       git log -1 --pretty="format:%ci" >committertime &&
> +       test_cmp authortime committertime
> +'
> +
> +test_expect_success '--committer-date-is-author-date works with rebase -r' '
> +       git checkout side &&
> +       GIT_AUTHOR_DATE="@1234 +0300" git merge --no-ff commit3 &&
> +       git rebase -r --root --committer-date-is-author-date &&
> +       git log --pretty="format:%ai" >authortime &&
> +       git log --pretty="format:%ci" >committertime &&
> +       test_cmp authortime committertime
> +'
> +
> +test_expect_success '--committer-date-is-author-date works when forking merge' '
> +       git checkout side &&
> +       GIT_AUTHOR_DATE="@1234 +0300" git merge --no-ff commit3 &&
> +       git rebase -r --root --strategy=resolve --committer-date-is-author-date &&
> +       git log --pretty="format:%ai" >authortime &&
> +       git log --pretty="format:%ci" >committertime &&
> +       test_cmp authortime committertime
> +
> +'
> +
> +test_expect_success '--committer-date-is-author-date works when committing conflict resolution' '
> +       git checkout commit2 &&
> +       GIT_AUTHOR_DATE="@1980 +0000" git commit --amend --only --reset-author &&
> +       git log -1 --format=%at HEAD >expect &&
> +       test_must_fail git rebase -m --committer-date-is-author-date \
> +               --onto HEAD^^ HEAD^ &&
> +       echo resolved > foo &&
> +       git add foo &&
> +       git rebase --continue &&
> +       git log -1 --format=%ct HEAD >actual &&
> +       test_cmp expect actual
> +'
> +
>  # This must be the last test in this file
>  test_expect_success '$EDITOR and friends are unchanged' '
>         test_editor_unchanged
> --
> 2.26.2

Does this implementation rely on the run_git_commit() path, i.e. is it
another place we'll need to fix up to avoid forking a subprocess, or
does it work with the try_to_commit() codepath as well?