am: support --empty=<option> to handle empty patches

Since that the command 'git-format-patch' can include patches of
commits that emit no changes, the 'git-am' command should also
support an option, named as '--empty', to specify how to handle
those empty patches. In this commit, we have implemented three
valid options ('stop', 'drop' and 'keep').

Signed-off-by: 徐沛文 (Aleen) <aleen42@vip.qq.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-am.txt b/Documentation/git-am.txt
index 0a4a984dfdecda8ef5d252e2a2883f6497f2cb1b..7676bd58ae7beda33544075ee1bae40426c66a75 100644 (file)
--- a/Documentation/git-am.txt
+++ b/Documentation/git-am.txt
@@ -16,6 +16,7 @@ SYNOPSIS
         [--exclude=<path>] [--include=<path>] [--reject] [-q | --quiet]
         [--[no-]scissors] [-S[<keyid>]] [--patch-format=<format>]
         [--quoted-cr=<action>]
+        [--empty=(stop|drop|keep)]
         [(<mbox> | <Maildir>)...]
 'git am' (--continue | --skip | --abort | --quit | --show-current-patch[=(diff|raw)])
 
@@ -63,6 +64,14 @@ OPTIONS
 --quoted-cr=<action>::
        This flag will be passed down to 'git mailinfo' (see linkgit:git-mailinfo[1]).
 
+--empty=(stop|drop|keep)::
+       By default, or when the option is set to 'stop', the command
+       errors out on an input e-mail message lacking a patch
+       and stops into the middle of the current am session. When this
+       option is set to 'drop', skip such an e-mail message instead.
+       When this option is set to 'keep', create an empty commit,
+       recording the contents of the e-mail message as its log.
+
 -m::
 --message-id::
        Pass the `-m` flag to 'git mailinfo' (see linkgit:git-mailinfo[1]),

diff --git a/builtin/am.c b/builtin/am.c
index 8677ea2348ab5b8017fc82cd1f8b79e4a7d20122..7a66ad237370ef89d24b4bc620b85dd7a3f24445 100644 (file)
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -87,6 +87,12 @@ enum show_patch_type {
        SHOW_PATCH_DIFF = 1,
 };
 
+enum empty_action {
+       STOP_ON_EMPTY_COMMIT = 0,  /* output errors and stop in the middle of an am session */
+       DROP_EMPTY_COMMIT,         /* skip with a notice message, unless "--quiet" has been passed */
+       KEEP_EMPTY_COMMIT,         /* keep recording as empty commits */
+};
+
 struct am_state {
        /* state directory path */
        char *dir;
@@ -118,6 +124,7 @@ struct am_state {
        int message_id;
        int scissors; /* enum scissors_type */
        int quoted_cr; /* enum quoted_cr_action */
+       int empty_type; /* enum empty_action */
        struct strvec git_apply_opts;
        const char *resolvemsg;
        int committer_date_is_author_date;
@@ -178,6 +185,25 @@ static int am_option_parse_quoted_cr(const struct option *opt,
        return 0;
 }
 
+static int am_option_parse_empty(const struct option *opt,
+                                    const char *arg, int unset)
+{
+       int *opt_value = opt->value;
+
+       BUG_ON_OPT_NEG(unset);
+
+       if (!strcmp(arg, "stop"))
+               *opt_value = STOP_ON_EMPTY_COMMIT;
+       else if (!strcmp(arg, "drop"))
+               *opt_value = DROP_EMPTY_COMMIT;
+       else if (!strcmp(arg, "keep"))
+               *opt_value = KEEP_EMPTY_COMMIT;
+       else
+               return error(_("Invalid value for --empty: %s"), arg);
+
+       return 0;
+}
+
 /**
  * Returns path relative to the am_state directory.
  */
@@ -1248,11 +1274,6 @@ static int parse_mail(struct am_state *state, const char *mail)
                goto finish;
        }
 
-       if (is_empty_or_missing_file(am_path(state, "patch"))) {
-               printf_ln(_("Patch is empty."));
-               die_user_resolve(state);
-       }
-
        strbuf_addstr(&msg, "\n\n");
        strbuf_addbuf(&msg, &mi.log_message);
        strbuf_stripspace(&msg, 0);
@@ -1763,6 +1784,7 @@ static void am_run(struct am_state *state, int resume)
        while (state->cur <= state->last) {
                const char *mail = am_path(state, msgnum(state));
                int apply_status;
+               int to_keep;
 
                reset_ident_date();
 
@@ -1792,8 +1814,29 @@ static void am_run(struct am_state *state, int resume)
                if (state->interactive && do_interactive(state))
                        goto next;
 
+               to_keep = 0;
+               if (is_empty_or_missing_file(am_path(state, "patch"))) {
+                       switch (state->empty_type) {
+                       case DROP_EMPTY_COMMIT:
+                               say(state, stdout, _("Skipping: %.*s"), linelen(state->msg), state->msg);
+                               goto next;
+                               break;
+                       case KEEP_EMPTY_COMMIT:
+                               to_keep = 1;
+                               say(state, stdout, _("Creating an empty commit: %.*s"),
+                                       linelen(state->msg), state->msg);
+                               break;
+                       case STOP_ON_EMPTY_COMMIT:
+                               printf_ln(_("Patch is empty."));
+                               die_user_resolve(state);
+                               break;
+                       }
+               }
+
                if (run_applypatch_msg_hook(state))
                        exit(1);
+               if (to_keep)
+                       goto commit;
 
                say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
@@ -1827,6 +1870,7 @@ static void am_run(struct am_state *state, int resume)
                        die_user_resolve(state);
                }
 
+commit:
                do_commit(state);
 
 next:
@@ -2357,6 +2401,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
                { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
                  N_("GPG-sign commits"),
                  PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
+               OPT_CALLBACK_F(STOP_ON_EMPTY_COMMIT, "empty", &state.empty_type, "{stop,drop,keep}",
+                 N_("how to handle empty patches"),
+                 PARSE_OPT_NONEG, am_option_parse_empty),
                OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
                        N_("(internal use for git-rebase)")),
                OPT_END()

diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 2aaaa0d7dedf68934e8d5b4c6610f1a859acbb29..f2a7a68eda062f180add55744309c241243eb4f3 100755 (executable)
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -196,6 +196,12 @@ test_expect_success setup '
 
        git format-patch -M --stdout lorem^ >rename-add.patch &&
 
+       git checkout -b empty-commit &&
+       git commit -m "empty commit" --allow-empty &&
+
+       : >empty.patch &&
+       git format-patch --always --stdout empty-commit^ >empty-commit.patch &&
+
        # reset time
        sane_unset test_tick &&
        test_tick
@@ -1152,4 +1158,48 @@ test_expect_success 'apply binary blob in partial clone' '
        git -C client am ../patch
 '
 
+test_expect_success 'an empty input file is error regardless of --empty option' '
+       test_when_finished "git am --abort || :" &&
+       test_must_fail git am --empty=drop empty.patch 2>actual &&
+       echo "Patch format detection failed." >expected &&
+       test_cmp expected actual
+'
+
+test_expect_success 'invalid when passing the --empty option alone' '
+       test_when_finished "git am --abort || :" &&
+       git checkout empty-commit^ &&
+       test_must_fail git am --empty empty-commit.patch 2>err &&
+       echo "error: Invalid value for --empty: empty-commit.patch" >expected &&
+       test_cmp expected err
+'
+
+test_expect_success 'a message without a patch is an error (default)' '
+       test_when_finished "git am --abort || :" &&
+       test_must_fail git am empty-commit.patch >err &&
+       grep "Patch is empty" err
+'
+
+test_expect_success 'a message without a patch is an error where an explicit "--empty=stop" is given' '
+       test_when_finished "git am --abort || :" &&
+       test_must_fail git am --empty=stop empty-commit.patch >err &&
+       grep "Patch is empty." err
+'
+
+test_expect_success 'a message without a patch will be skipped when "--empty=drop" is given' '
+       git am --empty=drop empty-commit.patch >output &&
+       git rev-parse empty-commit^ >expected &&
+       git rev-parse HEAD >actual &&
+       test_cmp expected actual &&
+       grep "Skipping: empty commit" output
+'
+
+test_expect_success 'record as an empty commit when meeting e-mail message that lacks a patch' '
+       git am --empty=keep empty-commit.patch >output &&
+       test_path_is_missing .git/rebase-apply &&
+       git show empty-commit --format="%B" >expected &&
+       git show HEAD --format="%B" >actual &&
+       grep -f actual expected &&
+       grep "Creating an empty commit: empty commit" output
+'
+
 test_done