cherry-pick: add `--empty` for more robust redundant commit handling
As with git-rebase(1) and git-am(1), git-cherry-pick(1) can result in a commit being made redundant if the content from the picked commit is already present in the target history. However, git-cherry-pick(1) does not have the same options available that git-rebase(1) and git-am(1) have. There are three things that can be done with these redundant commits: drop them, keep them, or have the cherry-pick stop and wait for the user to take an action. git-rebase(1) has the `--empty` option added in commit e98c4269c8 (rebase (interactive-backend): fix handling of commits that become empty, 2020-02-15), which handles all three of these scenarios. Similarly, git-am(1) got its own `--empty` in 7c096b8d61 (am: support --empty=<option> to handle empty patches, 2021-12-09). git-cherry-pick(1), on the other hand, only supports two of the three possiblities: Keep the redundant commits via `--keep-redundant-commits`, or have the cherry-pick fail by not specifying that option. There is no way to automatically drop redundant commits. In order to bring git-cherry-pick(1) more in-line with git-rebase(1) and git-am(1), this commit adds an `--empty` option to git-cherry-pick(1). It has the same three options (keep, drop, and stop), and largely behaves the same. The notable difference is that for git-cherry-pick(1), the default will be `stop`, which maintains the current behavior when the option is not specified. Like the existing `--keep-redundant-commits`, `--empty=keep` will imply `--allow-empty`. The `--keep-redundant-commits` option will be documented as a deprecated synonym of `--empty=keep`, and will be supported for backwards compatibility for the time being. Signed-off-by: Brian Lyles <brianmlyles@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Brian Lyles committed
Mar 25, 2024 at 18:16 UTC
ec79d763de617905bd9275de0b5941a160d6159b
5 files changed
+133
-9
Documentation/git-cherry-pick.txt
+23
-7
@@ -131,20 +131,36 @@ effect to your index in a row.
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even without this option. Note also, that use of this option only
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keeps commits that were initially empty (i.e. the commit recorded the
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same tree as its parent). Commits which are made empty due to a
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- previous commit are dropped. To force the inclusion of those commits
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- use `--keep-redundant-commits`.
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+ previous commit will cause the cherry-pick to fail. To force the
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+ inclusion of those commits, use `--empty=keep`.
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--allow-empty-message::
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By default, cherry-picking a commit with an empty message will fail.
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This option overrides that behavior, allowing commits with empty
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messages to be cherry picked.
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+--empty=(drop|keep|stop)::
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+ How to handle commits being cherry-picked that are redundant with
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+ changes already in the current history.
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++
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+--
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+`drop`;;
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+ The commit will be dropped.
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+`keep`;;
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+ The commit will be kept. Implies `--allow-empty`.
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+`stop`;;
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+ The cherry-pick will stop when the commit is applied, allowing
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+ you to examine the commit. This is the default behavior.
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+--
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++
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+Note that `--empty=drop` and `--empty=stop` only specify how to handle a
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+commit that was not initially empty, but rather became empty due to a previous
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+commit. Commits that were initially empty will still cause the cherry-pick to
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+fail unless one of `--empty=keep` or `--allow-empty` are specified.
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++
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+
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--keep-redundant-commits::
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- If a commit being cherry picked duplicates a commit already in the
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- current history, it will become empty. By default these
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- redundant commits cause `cherry-pick` to stop so the user can
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- examine the commit. This option overrides that behavior and
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- creates an empty commit object. Implies `--allow-empty`.
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+ Deprecated synonym for `--empty=keep`.
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--strategy=<strategy>::
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Use the given merge strategy. Should only be used once.
builtin/revert.c
+36
-1
@@ -43,6 +43,31 @@ static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
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return opts->action == REPLAY_REVERT ? revert_usage : cherry_pick_usage;
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}
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+enum empty_action {
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+ EMPTY_COMMIT_UNSPECIFIED = -1,
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+ STOP_ON_EMPTY_COMMIT, /* output errors and stop in the middle of a cherry-pick */
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+ DROP_EMPTY_COMMIT, /* skip with a notice message */
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+ KEEP_EMPTY_COMMIT, /* keep recording as empty commits */
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+};
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+
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+static int parse_opt_empty(const struct option *opt, const char *arg, int unset)
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+{
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+ int *opt_value = opt->value;
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+
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+ BUG_ON_OPT_NEG(unset);
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+
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+ if (!strcmp(arg, "stop"))
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+ *opt_value = STOP_ON_EMPTY_COMMIT;
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+ else if (!strcmp(arg, "drop"))
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+ *opt_value = DROP_EMPTY_COMMIT;
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+ else if (!strcmp(arg, "keep"))
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+ *opt_value = KEEP_EMPTY_COMMIT;
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+ else
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+ return error(_("invalid value for '%s': '%s'"), "--empty", arg);
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+
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+ return 0;
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+}
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+
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static int option_parse_m(const struct option *opt,
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const char *arg, int unset)
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{
@@ -85,6 +110,7 @@ static int run_sequencer(int argc, const char **argv, const char *prefix,
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const char * const * usage_str = revert_or_cherry_pick_usage(opts);
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const char *me = action_name(opts);
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const char *cleanup_arg = NULL;
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+ enum empty_action empty_opt = EMPTY_COMMIT_UNSPECIFIED;
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int cmd = 0;
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struct option base_options[] = {
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OPT_CMDMODE(0, "quit", &cmd, N_("end revert or cherry-pick sequence"), 'q'),
@@ -114,7 +140,10 @@ static int run_sequencer(int argc, const char **argv, const char *prefix,
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OPT_BOOL(0, "ff", &opts->allow_ff, N_("allow fast-forward")),
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OPT_BOOL(0, "allow-empty", &opts->allow_empty, N_("preserve initially empty commits")),
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OPT_BOOL(0, "allow-empty-message", &opts->allow_empty_message, N_("allow commits with empty messages")),
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- OPT_BOOL(0, "keep-redundant-commits", &opts->keep_redundant_commits, N_("keep redundant, empty commits")),
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+ OPT_BOOL(0, "keep-redundant-commits", &opts->keep_redundant_commits, N_("deprecated: use --empty=keep instead")),
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+ OPT_CALLBACK_F(0, "empty", &empty_opt, "(stop|drop|keep)",
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+ N_("how to handle commits that become empty"),
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+ PARSE_OPT_NONEG, parse_opt_empty),
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OPT_END(),
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};
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options = parse_options_concat(options, cp_extra);
@@ -134,6 +163,11 @@ static int run_sequencer(int argc, const char **argv, const char *prefix,
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prepare_repo_settings(the_repository);
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the_repository->settings.command_requires_full_index = 0;
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+ if (opts->action == REPLAY_PICK) {
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+ opts->drop_redundant_commits = (empty_opt == DROP_EMPTY_COMMIT);
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+ opts->keep_redundant_commits = opts->keep_redundant_commits || (empty_opt == KEEP_EMPTY_COMMIT);
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+ }
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+
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/* implies allow_empty */
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if (opts->keep_redundant_commits)
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opts->allow_empty = 1;
@@ -168,6 +202,7 @@ static int run_sequencer(int argc, const char **argv, const char *prefix,
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"--rerere-autoupdate", opts->allow_rerere_auto == RERERE_AUTOUPDATE,
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"--no-rerere-autoupdate", opts->allow_rerere_auto == RERERE_NOAUTOUPDATE,
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"--keep-redundant-commits", opts->keep_redundant_commits,
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+ "--empty", empty_opt != EMPTY_COMMIT_UNSPECIFIED,
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NULL);
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}
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sequencer.c
+6
@@ -2932,6 +2932,9 @@ static int populate_opts_cb(const char *key, const char *value,
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else if (!strcmp(key, "options.allow-empty-message"))
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opts->allow_empty_message =
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git_config_bool_or_int(key, value, ctx->kvi, &error_flag);
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+ else if (!strcmp(key, "options.drop-redundant-commits"))
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+ opts->drop_redundant_commits =
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+ git_config_bool_or_int(key, value, ctx->kvi, &error_flag);
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else if (!strcmp(key, "options.keep-redundant-commits"))
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opts->keep_redundant_commits =
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git_config_bool_or_int(key, value, ctx->kvi, &error_flag);
@@ -3476,6 +3479,9 @@ static int save_opts(struct replay_opts *opts)
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if (opts->allow_empty_message)
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res |= git_config_set_in_file_gently(opts_file,
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"options.allow-empty-message", "true");
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+ if (opts->drop_redundant_commits)
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+ res |= git_config_set_in_file_gently(opts_file,
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+ "options.drop-redundant-commits", "true");
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if (opts->keep_redundant_commits)
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res |= git_config_set_in_file_gently(opts_file,
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"options.keep-redundant-commits", "true");
t/t3505-cherry-pick-empty.sh
+36
-1
@@ -84,7 +84,7 @@ test_expect_success 'cherry-pick a commit that becomes no-op (prep)' '
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git commit -m "add file2 on the side"
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'
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-test_expect_success 'cherry-pick a no-op without --keep-redundant' '
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+test_expect_success 'cherry-pick a no-op with neither --keep-redundant nor --empty' '
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git reset --hard &&
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git checkout fork^0 &&
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test_must_fail git cherry-pick main
@@ -113,4 +113,39 @@ test_expect_success '--keep-redundant-commits is incompatible with operations' '
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git cherry-pick --abort
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'
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+test_expect_success '--empty is incompatible with operations' '
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+ test_must_fail git cherry-pick HEAD 2>output &&
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+ test_grep "The previous cherry-pick is now empty" output &&
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+ test_must_fail git cherry-pick --empty=stop --continue 2>output &&
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+ test_grep "fatal: cherry-pick: --empty cannot be used with --continue" output &&
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+ test_must_fail git cherry-pick --empty=stop --skip 2>output &&
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+ test_grep "fatal: cherry-pick: --empty cannot be used with --skip" output &&
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+ test_must_fail git cherry-pick --empty=stop --abort 2>output &&
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+ test_grep "fatal: cherry-pick: --empty cannot be used with --abort" output &&
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+ test_must_fail git cherry-pick --empty=stop --quit 2>output &&
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+ test_grep "fatal: cherry-pick: --empty cannot be used with --quit" output &&
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+ git cherry-pick --abort
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+'
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+
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+test_expect_success 'cherry-pick a no-op with --empty=stop' '
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+ git reset --hard &&
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+ git checkout fork^0 &&
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+ test_must_fail git cherry-pick --empty=stop main 2>output &&
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+ test_grep "The previous cherry-pick is now empty" output
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+'
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+
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+test_expect_success 'cherry-pick a no-op with --empty=drop' '
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+ git reset --hard &&
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+ git checkout fork^0 &&
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+ git cherry-pick --empty=drop main &&
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+ test_commit_message HEAD -m "add file2 on the side"
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+'
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+
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+test_expect_success 'cherry-pick a no-op with --empty=keep' '
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+ git reset --hard &&
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+ git checkout fork^0 &&
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+ git cherry-pick --empty=keep main &&
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+ test_commit_message HEAD -m "add file2 on main"
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+'
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+
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test_done
t/t3510-cherry-pick-sequence.sh
+32
@@ -90,6 +90,38 @@ test_expect_success 'cherry-pick persists opts correctly' '
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test_cmp expect actual
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'
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+test_expect_success 'cherry-pick persists --empty=stop correctly' '
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+ pristine_detach yetanotherpick &&
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+ # Picking `anotherpick` forces a conflict so that we stop. That
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+ # commit is then skipped, after which we pick `yetanotherpick`
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+ # while already on `yetanotherpick` to cause an empty commit
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+ test_must_fail git cherry-pick --empty=stop anotherpick yetanotherpick &&
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+ test_must_fail git cherry-pick --skip 2>msg &&
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+ test_grep "The previous cherry-pick is now empty" msg &&
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+ rm msg &&
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+ git cherry-pick --abort
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+'
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+
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+test_expect_success 'cherry-pick persists --empty=drop correctly' '
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+ pristine_detach yetanotherpick &&
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+ # Picking `anotherpick` forces a conflict so that we stop. That
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+ # commit is then skipped, after which we pick `yetanotherpick`
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+ # while already on `yetanotherpick` to cause an empty commit
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+ test_must_fail git cherry-pick --empty=drop anotherpick yetanotherpick &&
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+ git cherry-pick --skip &&
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+ test_cmp_rev yetanotherpick HEAD
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+'
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+
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+test_expect_success 'cherry-pick persists --empty=keep correctly' '
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+ pristine_detach yetanotherpick &&
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+ # Picking `anotherpick` forces a conflict so that we stop. That
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+ # commit is then skipped, after which we pick `yetanotherpick`
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+ # while already on `yetanotherpick` to cause an empty commit
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+ test_must_fail git cherry-pick --empty=keep anotherpick yetanotherpick &&
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+ git cherry-pick --skip &&
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+ test_cmp_rev yetanotherpick HEAD^
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+'
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+
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test_expect_success 'revert persists opts correctly' '
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pristine_detach initial &&
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# to make sure that the session to revert a sequence