builtin-am: implement --rebasing mode

Since 3041c32 (am: --rebasing, 2008-03-04), git-am.sh supported the
--rebasing option, which is used internally by git-rebase to tell git-am
that it is being used for its purpose. It would create the empty file
$state_dir/rebasing to help "completion" scripts tell if the ongoing
operation is am or rebase.

As of 0fbb95d (am: don't call mailinfo if $rebasing, 2012-06-26),
--rebasing also implies --3way as well.

Since a1549e1 (am: return control to caller, for housekeeping,
2013-05-12), git-am.sh would only clean up the state directory when it
is not --rebasing, instead deferring cleanup to git-rebase.sh.

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/am.c b/builtin/am.c
index a5d5e8c665cface79bde405b5c7a7159b32a37f7..440a65361a3d2f26d9dff3355610fda712a56164 100644 (file)
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -89,6 +89,7 @@ struct am_state {
        int quiet;
        int signoff;
        const char *resolvemsg;
+       int rebasing;
 };
 
 /**
@@ -364,6 +365,8 @@ static void am_load(struct am_state *state)
        read_state_file(&sb, state, "sign", 1);
        state->signoff = !strcmp(sb.buf, "t");
 
+       state->rebasing = !!file_exists(am_path(state, "rebasing"));
+
        strbuf_release(&sb);
 }
 
@@ -542,18 +545,29 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
                die(_("Failed to split patches."));
        }
 
+       if (state->rebasing)
+               state->threeway = 1;
+
        write_file(am_path(state, "threeway"), 1, state->threeway ? "t" : "f");
 
        write_file(am_path(state, "quiet"), 1, state->quiet ? "t" : "f");
 
        write_file(am_path(state, "sign"), 1, state->signoff ? "t" : "f");
 
+       if (state->rebasing)
+               write_file(am_path(state, "rebasing"), 1, "%s", "");
+       else
+               write_file(am_path(state, "applying"), 1, "%s", "");
+
        if (!get_sha1("HEAD", curr_head)) {
                write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
-               update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
+               if (!state->rebasing)
+                       update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
+                                       UPDATE_REFS_DIE_ON_ERR);
        } else {
                write_file(am_path(state, "abort-safety"), 1, "%s", "");
-               delete_ref("ORIG_HEAD", NULL, 0);
+               if (!state->rebasing)
+                       delete_ref("ORIG_HEAD", NULL, 0);
        }
 
        /*
@@ -1054,8 +1068,14 @@ static void am_run(struct am_state *state, int resume)
                am_next(state);
        }
 
-       am_destroy(state);
-       run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+       /*
+        * In rebasing mode, it's up to the caller to take care of
+        * housekeeping.
+        */
+       if (!state->rebasing) {
+               am_destroy(state);
+               run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+       }
 }
 
 /**
@@ -1325,6 +1345,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
                OPT_CMDMODE(0, "abort", &resume,
                        N_("restore the original branch and abort the patching operation."),
                        RESUME_ABORT),
+               OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
+                       N_("(internal use for git-rebase)")),
                OPT_END()
        };