revert: simplify getting commit subject in format_todo()
[gitweb.git] / builtin / revert.c
index 3117776c2c030bec03563f043c4dc8bb34eb17cd..0a86fecbd00d65f1f93c454b854ffd03c051ab3d 100644 (file)
@@ -13,6 +13,8 @@
 #include "rerere.h"
 #include "merge-recursive.h"
 #include "refs.h"
+#include "dir.h"
+#include "sequencer.h"
 
 /*
  * This implements the builtins revert and cherry-pick.
 
 static const char * const revert_usage[] = {
        "git revert [options] <commit-ish>",
+       "git revert <subcommand>",
        NULL
 };
 
 static const char * const cherry_pick_usage[] = {
        "git cherry-pick [options] <commit-ish>",
+       "git cherry-pick <subcommand>",
        NULL
 };
 
-static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
-static enum { REVERT, CHERRY_PICK } action;
-static struct commit *commit;
-static int commit_argc;
-static const char **commit_argv;
-static int allow_rerere_auto;
+enum replay_action { REVERT, CHERRY_PICK };
+enum replay_subcommand {
+       REPLAY_NONE,
+       REPLAY_REMOVE_STATE,
+       REPLAY_CONTINUE,
+       REPLAY_ROLLBACK
+};
+
+struct replay_opts {
+       enum replay_action action;
+       enum replay_subcommand subcommand;
 
-static const char *me;
+       /* Boolean options */
+       int edit;
+       int record_origin;
+       int no_commit;
+       int signoff;
+       int allow_ff;
+       int allow_rerere_auto;
 
-/* Merge strategy. */
-static const char *strategy;
-static const char **xopts;
-static size_t xopts_nr, xopts_alloc;
+       int mainline;
+
+       /* Merge strategy */
+       const char *strategy;
+       const char **xopts;
+       size_t xopts_nr, xopts_alloc;
+
+       /* Only used by REPLAY_NONE */
+       struct rev_info *revs;
+};
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
+static const char *action_name(const struct replay_opts *opts)
+{
+       return opts->action == REVERT ? "revert" : "cherry-pick";
+}
+
 static char *get_encoding(const char *message);
 
-static const char * const *revert_or_cherry_pick_usage(void)
+static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
 {
-       return action == REVERT ? revert_usage : cherry_pick_usage;
+       return opts->action == REVERT ? revert_usage : cherry_pick_usage;
 }
 
 static int option_parse_x(const struct option *opt,
                          const char *arg, int unset)
 {
+       struct replay_opts **opts_ptr = opt->value;
+       struct replay_opts *opts = *opts_ptr;
+
        if (unset)
                return 0;
 
-       ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
-       xopts[xopts_nr++] = xstrdup(arg);
+       ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
+       opts->xopts[opts->xopts_nr++] = xstrdup(arg);
        return 0;
 }
 
-static void parse_args(int argc, const char **argv)
+static void verify_opt_compatible(const char *me, const char *base_opt, ...)
+{
+       const char *this_opt;
+       va_list ap;
+
+       va_start(ap, base_opt);
+       while ((this_opt = va_arg(ap, const char *))) {
+               if (va_arg(ap, int))
+                       break;
+       }
+       va_end(ap);
+
+       if (this_opt)
+               die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
+}
+
+static void verify_opt_mutually_compatible(const char *me, ...)
 {
-       const char * const * usage_str = revert_or_cherry_pick_usage();
-       int noop;
+       const char *opt1, *opt2 = NULL;
+       va_list ap;
+
+       va_start(ap, me);
+       while ((opt1 = va_arg(ap, const char *))) {
+               if (va_arg(ap, int))
+                       break;
+       }
+       if (opt1) {
+               while ((opt2 = va_arg(ap, const char *))) {
+                       if (va_arg(ap, int))
+                               break;
+               }
+       }
+
+       if (opt1 && opt2)
+               die(_("%s: %s cannot be used with %s"), me, opt1, opt2);
+}
+
+static void parse_args(int argc, const char **argv, struct replay_opts *opts)
+{
+       const char * const * usage_str = revert_or_cherry_pick_usage(opts);
+       const char *me = action_name(opts);
+       int remove_state = 0;
+       int contin = 0;
+       int rollback = 0;
        struct option options[] = {
-               OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
-               OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
-               { OPTION_BOOLEAN, 'r', NULL, &noop, NULL, "no-op (backward compatibility)",
-                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 0 },
-               OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
-               OPT_INTEGER('m', "mainline", &mainline, "parent number"),
-               OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
-               OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
-               OPT_CALLBACK('X', "strategy-option", &xopts, "option",
+               OPT_BOOLEAN(0, "quit", &remove_state, "end revert or cherry-pick sequence"),
+               OPT_BOOLEAN(0, "continue", &contin, "resume revert or cherry-pick sequence"),
+               OPT_BOOLEAN(0, "abort", &rollback, "cancel revert or cherry-pick sequence"),
+               OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
+               OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
+               OPT_NOOP_NOARG('r', NULL),
+               OPT_BOOLEAN('s', "signoff", &opts->signoff, "add Signed-off-by:"),
+               OPT_INTEGER('m', "mainline", &opts->mainline, "parent number"),
+               OPT_RERERE_AUTOUPDATE(&opts->allow_rerere_auto),
+               OPT_STRING(0, "strategy", &opts->strategy, "strategy", "merge strategy"),
+               OPT_CALLBACK('X', "strategy-option", &opts, "option",
                        "option for merge strategy", option_parse_x),
                OPT_END(),
                OPT_END(),
                OPT_END(),
        };
 
-       if (action == CHERRY_PICK) {
+       if (opts->action == CHERRY_PICK) {
                struct option cp_extra[] = {
-                       OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
-                       OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
+                       OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
+                       OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
                        OPT_END(),
                };
                if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
                        die(_("program error"));
        }
 
-       commit_argc = parse_options(argc, argv, NULL, options, usage_str,
-                                   PARSE_OPT_KEEP_ARGV0 |
-                                   PARSE_OPT_KEEP_UNKNOWN);
-       if (commit_argc < 2)
-               usage_with_options(usage_str, options);
+       argc = parse_options(argc, argv, NULL, options, usage_str,
+                       PARSE_OPT_KEEP_ARGV0 |
+                       PARSE_OPT_KEEP_UNKNOWN);
+
+       /* Check for incompatible subcommands */
+       verify_opt_mutually_compatible(me,
+                               "--quit", remove_state,
+                               "--continue", contin,
+                               "--abort", rollback,
+                               NULL);
+
+       /* Set the subcommand */
+       if (remove_state)
+               opts->subcommand = REPLAY_REMOVE_STATE;
+       else if (contin)
+               opts->subcommand = REPLAY_CONTINUE;
+       else if (rollback)
+               opts->subcommand = REPLAY_ROLLBACK;
+       else
+               opts->subcommand = REPLAY_NONE;
+
+       /* Check for incompatible command line arguments */
+       if (opts->subcommand != REPLAY_NONE) {
+               char *this_operation;
+               if (opts->subcommand == REPLAY_REMOVE_STATE)
+                       this_operation = "--quit";
+               else if (opts->subcommand == REPLAY_CONTINUE)
+                       this_operation = "--continue";
+               else {
+                       assert(opts->subcommand == REPLAY_ROLLBACK);
+                       this_operation = "--abort";
+               }
 
-       commit_argv = argv;
+               verify_opt_compatible(me, this_operation,
+                               "--no-commit", opts->no_commit,
+                               "--signoff", opts->signoff,
+                               "--mainline", opts->mainline,
+                               "--strategy", opts->strategy ? 1 : 0,
+                               "--strategy-option", opts->xopts ? 1 : 0,
+                               "-x", opts->record_origin,
+                               "--ff", opts->allow_ff,
+                               NULL);
+       }
+
+       if (opts->allow_ff)
+               verify_opt_compatible(me, "--ff",
+                               "--signoff", opts->signoff,
+                               "--no-commit", opts->no_commit,
+                               "-x", opts->record_origin,
+                               "--edit", opts->edit,
+                               NULL);
+
+       if (opts->subcommand != REPLAY_NONE) {
+               opts->revs = NULL;
+       } else {
+               opts->revs = xmalloc(sizeof(*opts->revs));
+               init_revisions(opts->revs, NULL);
+               opts->revs->no_walk = 1;
+               if (argc < 2)
+                       usage_with_options(usage_str, options);
+               argc = setup_revisions(argc, argv, opts->revs, NULL);
+       }
+
+       if (argc > 1)
+               usage_with_options(usage_str, options);
 }
 
 struct commit_message {
@@ -116,25 +245,25 @@ struct commit_message {
        const char *message;
 };
 
-static int get_message(const char *raw_message, struct commit_message *out)
+static int get_message(struct commit *commit, struct commit_message *out)
 {
        const char *encoding;
        const char *abbrev, *subject;
        int abbrev_len, subject_len;
        char *q;
 
-       if (!raw_message)
+       if (!commit->buffer)
                return -1;
-       encoding = get_encoding(raw_message);
+       encoding = get_encoding(commit->buffer);
        if (!encoding)
                encoding = "UTF-8";
        if (!git_commit_encoding)
                git_commit_encoding = "UTF-8";
 
        out->reencoded_message = NULL;
-       out->message = raw_message;
+       out->message = commit->buffer;
        if (strcmp(encoding, git_commit_encoding))
-               out->reencoded_message = reencode_string(raw_message,
+               out->reencoded_message = reencode_string(commit->buffer,
                                        git_commit_encoding, encoding);
        if (out->reencoded_message)
                out->message = out->reencoded_message;
@@ -167,9 +296,6 @@ static char *get_encoding(const char *message)
 {
        const char *p = message, *eol;
 
-       if (!p)
-               die (_("Could not read commit message of %s"),
-                               sha1_to_hex(commit->object.sha1));
        while (*p && *p != '\n') {
                for (eol = p + 1; *eol && *eol != '\n'; eol++)
                        ; /* do nothing */
@@ -185,45 +311,24 @@ static char *get_encoding(const char *message)
        return NULL;
 }
 
-static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
-{
-       const char *p = message;
-       while (*p && (*p != '\n' || p[1] != '\n'))
-               p++;
-
-       if (!*p)
-               strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
-
-       p += 2;
-       strbuf_addstr(msgbuf, p);
-}
-
-static void write_cherry_pick_head(void)
+static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 {
+       const char *filename;
        int fd;
        struct strbuf buf = STRBUF_INIT;
 
        strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 
-       fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
+       filename = git_path("%s", pseudoref);
+       fd = open(filename, O_WRONLY | O_CREAT, 0666);
        if (fd < 0)
-               die_errno(_("Could not open '%s' for writing"),
-                         git_path("CHERRY_PICK_HEAD"));
+               die_errno(_("Could not open '%s' for writing"), filename);
        if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
-               die_errno(_("Could not write to '%s'"), git_path("CHERRY_PICK_HEAD"));
+               die_errno(_("Could not write to '%s'"), filename);
        strbuf_release(&buf);
 }
 
-static void advise(const char *advice, ...)
-{
-       va_list params;
-
-       va_start(params, advice);
-       vreportf("hint: ", advice, params);
-       va_end(params);
-}
-
-static void print_advice(void)
+static void print_advice(int show_hint)
 {
        char *msg = getenv("GIT_CHERRY_PICK_HELP");
 
@@ -238,9 +343,11 @@ static void print_advice(void)
                return;
        }
 
-       advise("after resolving the conflicts, mark the corrected paths");
-       advise("with 'git add <paths>' or 'git rm <paths>'");
-       advise("and commit the result with 'git commit'");
+       if (show_hint) {
+               advise("after resolving the conflicts, mark the corrected paths");
+               advise("with 'git add <paths>' or 'git rm <paths>'");
+               advise("and commit the result with 'git commit'");
+       }
 }
 
 static void write_message(struct strbuf *msgbuf, const char *filename)
@@ -250,7 +357,7 @@ static void write_message(struct strbuf *msgbuf, const char *filename)
        int msg_fd = hold_lock_file_for_update(&msg_file, filename,
                                               LOCK_DIE_ON_ERROR);
        if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
-               die_errno(_("Could not write to %s."), filename);
+               die_errno(_("Could not write to %s"), filename);
        strbuf_release(msgbuf);
        if (commit_lock_file(&msg_file) < 0)
                die(_("Error wrapping up %s"), filename);
@@ -261,25 +368,20 @@ static struct tree *empty_tree(void)
        return lookup_tree((const unsigned char *)EMPTY_TREE_SHA1_BIN);
 }
 
-static NORETURN void die_dirty_index(const char *me)
+static int error_dirty_index(struct replay_opts *opts)
 {
-       if (read_cache_unmerged()) {
-               die_resolve_conflict(me);
-       } else {
-               if (advice_commit_before_merge) {
-                       if (action == REVERT)
-                               die(_("Your local changes would be overwritten by revert.\n"
-                                         "Please, commit your changes or stash them to proceed."));
-                       else
-                               die(_("Your local changes would be overwritten by cherry-pick.\n"
-                                         "Please, commit your changes or stash them to proceed."));
-               } else {
-                       if (action == REVERT)
-                               die(_("Your local changes would be overwritten by revert.\n"));
-                       else
-                               die(_("Your local changes would be overwritten by cherry-pick.\n"));
-               }
-       }
+       if (read_cache_unmerged())
+               return error_resolve_conflict(action_name(opts));
+
+       /* Different translation strings for cherry-pick and revert */
+       if (opts->action == CHERRY_PICK)
+               error(_("Your local changes would be overwritten by cherry-pick."));
+       else
+               error(_("Your local changes would be overwritten by revert."));
+
+       if (advice_commit_before_merge)
+               advise(_("Commit your changes or stash them to proceed."));
+       return -1;
 }
 
 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
@@ -295,7 +397,8 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 
 static int do_recursive_merge(struct commit *base, struct commit *next,
                              const char *base_label, const char *next_label,
-                             unsigned char *head, struct strbuf *msgbuf)
+                             unsigned char *head, struct strbuf *msgbuf,
+                             struct replay_opts *opts)
 {
        struct merge_options o;
        struct tree *result, *next_tree, *base_tree, *head_tree;
@@ -316,7 +419,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
        next_tree = next ? next->tree : empty_tree();
        base_tree = base ? base->tree : empty_tree();
 
-       for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
+       for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
                parse_merge_opt(&o, *xopt);
 
        clean = merge_trees(&o,
@@ -327,7 +430,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
            (write_cache(index_fd, active_cache, active_nr) ||
             commit_locked_index(&index_lock)))
                /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
-               die(_("%s: Unable to write new index file"), me);
+               die(_("%s: Unable to write new index file"), action_name(opts));
        rollback_lock_file(&index_lock);
 
        if (!clean) {
@@ -356,7 +459,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
  * If we are revert, or if our cherry-pick results in a hand merge,
  * we had better say that the current user is responsible for that.
  */
-static int run_git_commit(const char *defmsg)
+static int run_git_commit(const char *defmsg, struct replay_opts *opts)
 {
        /* 6 is max possible length of our args array including NULL */
        const char *args[6];
@@ -364,9 +467,9 @@ static int run_git_commit(const char *defmsg)
 
        args[i++] = "commit";
        args[i++] = "-n";
-       if (signoff)
+       if (opts->signoff)
                args[i++] = "-s";
-       if (!edit) {
+       if (!opts->edit) {
                args[i++] = "-F";
                args[i++] = defmsg;
        }
@@ -375,7 +478,7 @@ static int run_git_commit(const char *defmsg)
        return run_command_v_opt(args, RUN_GIT_CMD);
 }
 
-static int do_pick_commit(void)
+static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 {
        unsigned char head[20];
        struct commit *base, *next, *parent;
@@ -385,7 +488,7 @@ static int do_pick_commit(void)
        struct strbuf msgbuf = STRBUF_INIT;
        int res;
 
-       if (no_commit) {
+       if (opts->no_commit) {
                /*
                 * We do not intend to commit immediately.  We just want to
                 * merge the differences in, so let's compute the tree
@@ -396,9 +499,9 @@ static int do_pick_commit(void)
                        die (_("Your index file is unmerged."));
        } else {
                if (get_sha1("HEAD", head))
-                       die (_("You do not have a valid HEAD"));
+                       return error(_("You do not have a valid HEAD"));
                if (index_differs_from("HEAD", 0))
-                       die_dirty_index(me);
+                       return error_dirty_index(opts);
        }
        discard_cache();
 
@@ -410,36 +513,36 @@ static int do_pick_commit(void)
                int cnt;
                struct commit_list *p;
 
-               if (!mainline)
-                       die(_("Commit %s is a merge but no -m option was given."),
-                           sha1_to_hex(commit->object.sha1));
+               if (!opts->mainline)
+                       return error(_("Commit %s is a merge but no -m option was given."),
+                               sha1_to_hex(commit->object.sha1));
 
                for (cnt = 1, p = commit->parents;
-                    cnt != mainline && p;
+                    cnt != opts->mainline && p;
                     cnt++)
                        p = p->next;
-               if (cnt != mainline || !p)
-                       die(_("Commit %s does not have parent %d"),
-                           sha1_to_hex(commit->object.sha1), mainline);
+               if (cnt != opts->mainline || !p)
+                       return error(_("Commit %s does not have parent %d"),
+                               sha1_to_hex(commit->object.sha1), opts->mainline);
                parent = p->item;
-       } else if (0 < mainline)
-               die(_("Mainline was specified but commit %s is not a merge."),
-                   sha1_to_hex(commit->object.sha1));
+       } else if (0 < opts->mainline)
+               return error(_("Mainline was specified but commit %s is not a merge."),
+                       sha1_to_hex(commit->object.sha1));
        else
                parent = commit->parents->item;
 
-       if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
+       if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
                return fast_forward_to(commit->object.sha1, head);
 
        if (parent && parse_commit(parent) < 0)
                /* TRANSLATORS: The first %s will be "revert" or
                   "cherry-pick", the second %s a SHA1 */
-               die(_("%s: cannot parse parent commit %s"),
-                   me, sha1_to_hex(parent->object.sha1));
+               return error(_("%s: cannot parse parent commit %s"),
+                       action_name(opts), sha1_to_hex(parent->object.sha1));
 
-       if (get_message(commit->buffer, &msg) != 0)
-               die(_("Cannot get commit message for %s"),
-                               sha1_to_hex(commit->object.sha1));
+       if (get_message(commit, &msg) != 0)
+               return error(_("Cannot get commit message for %s"),
+                       sha1_to_hex(commit->object.sha1));
 
        /*
         * "commit" is an existing commit.  We would want to apply
@@ -450,7 +553,7 @@ static int do_pick_commit(void)
 
        defmsg = git_pathdup("MERGE_MSG");
 
-       if (action == REVERT) {
+       if (opts->action == REVERT) {
                base = commit;
                base_label = msg.label;
                next = parent;
@@ -466,23 +569,34 @@ static int do_pick_commit(void)
                }
                strbuf_addstr(&msgbuf, ".\n");
        } else {
+               const char *p;
+
                base = parent;
                base_label = msg.parent_label;
                next = commit;
                next_label = msg.label;
-               add_message_to_msg(&msgbuf, msg.message);
-               if (no_replay) {
+
+               /*
+                * Append the commit log message to msgbuf; it starts
+                * after the tree, parent, author, committer
+                * information followed by "\n\n".
+                */
+               p = strstr(msg.message, "\n\n");
+               if (p) {
+                       p += 2;
+                       strbuf_addstr(&msgbuf, p);
+               }
+
+               if (opts->record_origin) {
                        strbuf_addstr(&msgbuf, "(cherry picked from commit ");
                        strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
                        strbuf_addstr(&msgbuf, ")\n");
                }
-               if (!no_commit)
-                       write_cherry_pick_head();
        }
 
-       if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
+       if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REVERT) {
                res = do_recursive_merge(base, next, base_label, next_label,
-                                        head, &msgbuf);
+                                        head, &msgbuf, opts);
                write_message(&msgbuf, defmsg);
        } else {
                struct commit_list *common = NULL;
@@ -492,23 +606,34 @@ static int do_pick_commit(void)
 
                commit_list_insert(base, &common);
                commit_list_insert(next, &remotes);
-               res = try_merge_command(strategy, xopts_nr, xopts, common,
-                                       sha1_to_hex(head), remotes);
+               res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
+                                       common, sha1_to_hex(head), remotes);
                free_commit_list(common);
                free_commit_list(remotes);
        }
 
+       /*
+        * If the merge was clean or if it failed due to conflict, we write
+        * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
+        * However, if the merge did not even start, then we don't want to
+        * write it at all.
+        */
+       if (opts->action == CHERRY_PICK && !opts->no_commit && (res == 0 || res == 1))
+               write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
+       if (opts->action == REVERT && ((opts->no_commit && res == 0) || res == 1))
+               write_cherry_pick_head(commit, "REVERT_HEAD");
+
        if (res) {
-               error(action == REVERT
+               error(opts->action == REVERT
                      ? _("could not revert %s... %s")
                      : _("could not apply %s... %s"),
                      find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
                      msg.subject);
-               print_advice();
-               rerere(allow_rerere_auto);
+               print_advice(res == 1);
+               rerere(opts->allow_rerere_auto);
        } else {
-               if (!no_commit)
-                       res = run_git_commit(defmsg);
+               if (!opts->no_commit)
+                       res = run_git_commit(defmsg, opts);
        }
 
        free_message(&msg);
@@ -517,84 +642,525 @@ static int do_pick_commit(void)
        return res;
 }
 
-static void prepare_revs(struct rev_info *revs)
+static void prepare_revs(struct replay_opts *opts)
 {
-       int argc;
-
-       init_revisions(revs, NULL);
-       revs->no_walk = 1;
-       if (action != REVERT)
-               revs->reverse = 1;
-
-       argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
-       if (argc > 1)
-               usage(*revert_or_cherry_pick_usage());
+       if (opts->action != REVERT)
+               opts->revs->reverse ^= 1;
 
-       if (prepare_revision_walk(revs))
+       if (prepare_revision_walk(opts->revs))
                die(_("revision walk setup failed"));
 
-       if (!revs->commits)
+       if (!opts->revs->commits)
                die(_("empty commit set passed"));
 }
 
-static void read_and_refresh_cache(const char *me)
+static void read_and_refresh_cache(struct replay_opts *opts)
 {
        static struct lock_file index_lock;
        int index_fd = hold_locked_index(&index_lock, 0);
        if (read_index_preload(&the_index, NULL) < 0)
-               die(_("git %s: failed to read the index"), me);
+               die(_("git %s: failed to read the index"), action_name(opts));
        refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
        if (the_index.cache_changed) {
                if (write_index(&the_index, index_fd) ||
                    commit_locked_index(&index_lock))
-                       die(_("git %s: failed to refresh the index"), me);
+                       die(_("git %s: failed to refresh the index"), action_name(opts));
        }
        rollback_lock_file(&index_lock);
 }
 
-static int revert_or_cherry_pick(int argc, const char **argv)
+/*
+ * Append a commit to the end of the commit_list.
+ *
+ * next starts by pointing to the variable that holds the head of an
+ * empty commit_list, and is updated to point to the "next" field of
+ * the last item on the list as new commits are appended.
+ *
+ * Usage example:
+ *
+ *     struct commit_list *list;
+ *     struct commit_list **next = &list;
+ *
+ *     next = commit_list_append(c1, next);
+ *     next = commit_list_append(c2, next);
+ *     assert(commit_list_count(list) == 2);
+ *     return list;
+ */
+static struct commit_list **commit_list_append(struct commit *commit,
+                                              struct commit_list **next)
 {
-       struct rev_info revs;
+       struct commit_list *new = xmalloc(sizeof(struct commit_list));
+       new->item = commit;
+       *next = new;
+       new->next = NULL;
+       return &new->next;
+}
 
-       git_config(git_default_config, NULL);
-       me = action == REVERT ? "revert" : "cherry-pick";
-       setenv(GIT_REFLOG_ACTION, me, 0);
-       parse_args(argc, argv);
+static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
+               struct replay_opts *opts)
+{
+       struct commit_list *cur = NULL;
+       const char *sha1_abbrev = NULL;
+       const char *action_str = opts->action == REVERT ? "revert" : "pick";
+       const char *subject;
+       int subject_len;
 
-       if (allow_ff) {
-               if (signoff)
-                       die(_("cherry-pick --ff cannot be used with --signoff"));
-               if (no_commit)
-                       die(_("cherry-pick --ff cannot be used with --no-commit"));
-               if (no_replay)
-                       die(_("cherry-pick --ff cannot be used with -x"));
-               if (edit)
-                       die(_("cherry-pick --ff cannot be used with --edit"));
+       for (cur = todo_list; cur; cur = cur->next) {
+               sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
+               subject_len = find_commit_subject(cur->item->buffer, &subject);
+               strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
+                       subject_len, subject);
        }
+       return 0;
+}
 
-       read_and_refresh_cache(me);
+static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
+{
+       unsigned char commit_sha1[20];
+       enum replay_action action;
+       char *end_of_object_name;
+       int saved, status, padding;
+
+       if (!prefixcmp(bol, "pick")) {
+               action = CHERRY_PICK;
+               bol += strlen("pick");
+       } else if (!prefixcmp(bol, "revert")) {
+               action = REVERT;
+               bol += strlen("revert");
+       } else
+               return NULL;
+
+       /* Eat up extra spaces/ tabs before object name */
+       padding = strspn(bol, " \t");
+       if (!padding)
+               return NULL;
+       bol += padding;
+
+       end_of_object_name = bol + strcspn(bol, " \t\n");
+       saved = *end_of_object_name;
+       *end_of_object_name = '\0';
+       status = get_sha1(bol, commit_sha1);
+       *end_of_object_name = saved;
 
-       prepare_revs(&revs);
+       /*
+        * Verify that the action matches up with the one in
+        * opts; we don't support arbitrary instructions
+        */
+       if (action != opts->action) {
+               const char *action_str;
+               action_str = action == REVERT ? "revert" : "cherry-pick";
+               error(_("Cannot %s during a %s"), action_str, action_name(opts));
+               return NULL;
+       }
+
+       if (status < 0)
+               return NULL;
+
+       return lookup_commit_reference(commit_sha1);
+}
+
+static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
+                       struct replay_opts *opts)
+{
+       struct commit_list **next = todo_list;
+       struct commit *commit;
+       char *p = buf;
+       int i;
+
+       for (i = 1; *p; i++) {
+               char *eol = strchrnul(p, '\n');
+               commit = parse_insn_line(p, eol, opts);
+               if (!commit)
+                       return error(_("Could not parse line %d."), i);
+               next = commit_list_append(commit, next);
+               p = *eol ? eol + 1 : eol;
+       }
+       if (!*todo_list)
+               return error(_("No commits parsed."));
+       return 0;
+}
+
+static void read_populate_todo(struct commit_list **todo_list,
+                       struct replay_opts *opts)
+{
+       const char *todo_file = git_path(SEQ_TODO_FILE);
+       struct strbuf buf = STRBUF_INIT;
+       int fd, res;
+
+       fd = open(todo_file, O_RDONLY);
+       if (fd < 0)
+               die_errno(_("Could not open %s"), todo_file);
+       if (strbuf_read(&buf, fd, 0) < 0) {
+               close(fd);
+               strbuf_release(&buf);
+               die(_("Could not read %s."), todo_file);
+       }
+       close(fd);
+
+       res = parse_insn_buffer(buf.buf, todo_list, opts);
+       strbuf_release(&buf);
+       if (res)
+               die(_("Unusable instruction sheet: %s"), todo_file);
+}
+
+static int populate_opts_cb(const char *key, const char *value, void *data)
+{
+       struct replay_opts *opts = data;
+       int error_flag = 1;
+
+       if (!value)
+               error_flag = 0;
+       else if (!strcmp(key, "options.no-commit"))
+               opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
+       else if (!strcmp(key, "options.edit"))
+               opts->edit = git_config_bool_or_int(key, value, &error_flag);
+       else if (!strcmp(key, "options.signoff"))
+               opts->signoff = git_config_bool_or_int(key, value, &error_flag);
+       else if (!strcmp(key, "options.record-origin"))
+               opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
+       else if (!strcmp(key, "options.allow-ff"))
+               opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
+       else if (!strcmp(key, "options.mainline"))
+               opts->mainline = git_config_int(key, value);
+       else if (!strcmp(key, "options.strategy"))
+               git_config_string(&opts->strategy, key, value);
+       else if (!strcmp(key, "options.strategy-option")) {
+               ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
+               opts->xopts[opts->xopts_nr++] = xstrdup(value);
+       } else
+               return error(_("Invalid key: %s"), key);
+
+       if (!error_flag)
+               return error(_("Invalid value for %s: %s"), key, value);
+
+       return 0;
+}
 
-       while ((commit = get_revision(&revs))) {
-               int res = do_pick_commit();
+static void read_populate_opts(struct replay_opts **opts_ptr)
+{
+       const char *opts_file = git_path(SEQ_OPTS_FILE);
+
+       if (!file_exists(opts_file))
+               return;
+       if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
+               die(_("Malformed options sheet: %s"), opts_file);
+}
+
+static void walk_revs_populate_todo(struct commit_list **todo_list,
+                               struct replay_opts *opts)
+{
+       struct commit *commit;
+       struct commit_list **next;
+
+       prepare_revs(opts);
+
+       next = todo_list;
+       while ((commit = get_revision(opts->revs)))
+               next = commit_list_append(commit, next);
+}
+
+static int create_seq_dir(void)
+{
+       const char *seq_dir = git_path(SEQ_DIR);
+
+       if (file_exists(seq_dir)) {
+               error(_("a cherry-pick or revert is already in progress"));
+               advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
+               return -1;
+       }
+       else if (mkdir(seq_dir, 0777) < 0)
+               die_errno(_("Could not create sequencer directory %s"), seq_dir);
+       return 0;
+}
+
+static void save_head(const char *head)
+{
+       const char *head_file = git_path(SEQ_HEAD_FILE);
+       static struct lock_file head_lock;
+       struct strbuf buf = STRBUF_INIT;
+       int fd;
+
+       fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
+       strbuf_addf(&buf, "%s\n", head);
+       if (write_in_full(fd, buf.buf, buf.len) < 0)
+               die_errno(_("Could not write to %s"), head_file);
+       if (commit_lock_file(&head_lock) < 0)
+               die(_("Error wrapping up %s."), head_file);
+}
+
+static int reset_for_rollback(const unsigned char *sha1)
+{
+       const char *argv[4];    /* reset --merge <arg> + NULL */
+       argv[0] = "reset";
+       argv[1] = "--merge";
+       argv[2] = sha1_to_hex(sha1);
+       argv[3] = NULL;
+       return run_command_v_opt(argv, RUN_GIT_CMD);
+}
+
+static int rollback_single_pick(void)
+{
+       unsigned char head_sha1[20];
+
+       if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
+           !file_exists(git_path("REVERT_HEAD")))
+               return error(_("no cherry-pick or revert in progress"));
+       if (!resolve_ref("HEAD", head_sha1, 0, NULL))
+               return error(_("cannot resolve HEAD"));
+       if (is_null_sha1(head_sha1))
+               return error(_("cannot abort from a branch yet to be born"));
+       return reset_for_rollback(head_sha1);
+}
+
+static int sequencer_rollback(struct replay_opts *opts)
+{
+       const char *filename;
+       FILE *f;
+       unsigned char sha1[20];
+       struct strbuf buf = STRBUF_INIT;
+
+       filename = git_path(SEQ_HEAD_FILE);
+       f = fopen(filename, "r");
+       if (!f && errno == ENOENT) {
+               /*
+                * There is no multiple-cherry-pick in progress.
+                * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
+                * a single-cherry-pick in progress, abort that.
+                */
+               return rollback_single_pick();
+       }
+       if (!f)
+               return error(_("cannot open %s: %s"), filename,
+                                               strerror(errno));
+       if (strbuf_getline(&buf, f, '\n')) {
+               error(_("cannot read %s: %s"), filename, ferror(f) ?
+                       strerror(errno) : _("unexpected end of file"));
+               fclose(f);
+               goto fail;
+       }
+       fclose(f);
+       if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
+               error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
+                       filename);
+               goto fail;
+       }
+       if (reset_for_rollback(sha1))
+               goto fail;
+       remove_sequencer_state();
+       strbuf_release(&buf);
+       return 0;
+fail:
+       strbuf_release(&buf);
+       return -1;
+}
+
+static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
+{
+       const char *todo_file = git_path(SEQ_TODO_FILE);
+       static struct lock_file todo_lock;
+       struct strbuf buf = STRBUF_INIT;
+       int fd;
+
+       fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
+       if (format_todo(&buf, todo_list, opts) < 0)
+               die(_("Could not format %s."), todo_file);
+       if (write_in_full(fd, buf.buf, buf.len) < 0) {
+               strbuf_release(&buf);
+               die_errno(_("Could not write to %s"), todo_file);
+       }
+       if (commit_lock_file(&todo_lock) < 0) {
+               strbuf_release(&buf);
+               die(_("Error wrapping up %s."), todo_file);
+       }
+       strbuf_release(&buf);
+}
+
+static void save_opts(struct replay_opts *opts)
+{
+       const char *opts_file = git_path(SEQ_OPTS_FILE);
+
+       if (opts->no_commit)
+               git_config_set_in_file(opts_file, "options.no-commit", "true");
+       if (opts->edit)
+               git_config_set_in_file(opts_file, "options.edit", "true");
+       if (opts->signoff)
+               git_config_set_in_file(opts_file, "options.signoff", "true");
+       if (opts->record_origin)
+               git_config_set_in_file(opts_file, "options.record-origin", "true");
+       if (opts->allow_ff)
+               git_config_set_in_file(opts_file, "options.allow-ff", "true");
+       if (opts->mainline) {
+               struct strbuf buf = STRBUF_INIT;
+               strbuf_addf(&buf, "%d", opts->mainline);
+               git_config_set_in_file(opts_file, "options.mainline", buf.buf);
+               strbuf_release(&buf);
+       }
+       if (opts->strategy)
+               git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
+       if (opts->xopts) {
+               int i;
+               for (i = 0; i < opts->xopts_nr; i++)
+                       git_config_set_multivar_in_file(opts_file,
+                                                       "options.strategy-option",
+                                                       opts->xopts[i], "^$", 0);
+       }
+}
+
+static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
+{
+       struct commit_list *cur;
+       int res;
+
+       setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
+       if (opts->allow_ff)
+               assert(!(opts->signoff || opts->no_commit ||
+                               opts->record_origin || opts->edit));
+       read_and_refresh_cache(opts);
+
+       for (cur = todo_list; cur; cur = cur->next) {
+               save_todo(cur, opts);
+               res = do_pick_commit(cur->item, opts);
                if (res)
                        return res;
        }
 
+       /*
+        * Sequence of picks finished successfully; cleanup by
+        * removing the .git/sequencer directory
+        */
+       remove_sequencer_state();
        return 0;
 }
 
+static int continue_single_pick(void)
+{
+       const char *argv[] = { "commit", NULL };
+
+       if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
+           !file_exists(git_path("REVERT_HEAD")))
+               return error(_("no cherry-pick or revert in progress"));
+       return run_command_v_opt(argv, RUN_GIT_CMD);
+}
+
+static int sequencer_continue(struct replay_opts *opts)
+{
+       struct commit_list *todo_list = NULL;
+
+       if (!file_exists(git_path(SEQ_TODO_FILE)))
+               return continue_single_pick();
+       read_populate_opts(&opts);
+       read_populate_todo(&todo_list, opts);
+
+       /* Verify that the conflict has been resolved */
+       if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
+           file_exists(git_path("REVERT_HEAD"))) {
+               int ret = continue_single_pick();
+               if (ret)
+                       return ret;
+       }
+       if (index_differs_from("HEAD", 0))
+               return error_dirty_index(opts);
+       todo_list = todo_list->next;
+       return pick_commits(todo_list, opts);
+}
+
+static int single_pick(struct commit *cmit, struct replay_opts *opts)
+{
+       setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
+       return do_pick_commit(cmit, opts);
+}
+
+static int pick_revisions(struct replay_opts *opts)
+{
+       struct commit_list *todo_list = NULL;
+       unsigned char sha1[20];
+
+       if (opts->subcommand == REPLAY_NONE)
+               assert(opts->revs);
+
+       read_and_refresh_cache(opts);
+
+       /*
+        * Decide what to do depending on the arguments; a fresh
+        * cherry-pick should be handled differently from an existing
+        * one that is being continued
+        */
+       if (opts->subcommand == REPLAY_REMOVE_STATE) {
+               remove_sequencer_state();
+               return 0;
+       }
+       if (opts->subcommand == REPLAY_ROLLBACK)
+               return sequencer_rollback(opts);
+       if (opts->subcommand == REPLAY_CONTINUE)
+               return sequencer_continue(opts);
+
+       /*
+        * If we were called as "git cherry-pick <commit>", just
+        * cherry-pick/revert it, set CHERRY_PICK_HEAD /
+        * REVERT_HEAD, and don't touch the sequencer state.
+        * This means it is possible to cherry-pick in the middle
+        * of a cherry-pick sequence.
+        */
+       if (opts->revs->cmdline.nr == 1 &&
+           opts->revs->cmdline.rev->whence == REV_CMD_REV &&
+           opts->revs->no_walk &&
+           !opts->revs->cmdline.rev->flags) {
+               struct commit *cmit;
+               if (prepare_revision_walk(opts->revs))
+                       die(_("revision walk setup failed"));
+               cmit = get_revision(opts->revs);
+               if (!cmit || get_revision(opts->revs))
+                       die("BUG: expected exactly one commit from walk");
+               return single_pick(cmit, opts);
+       }
+
+       /*
+        * Start a new cherry-pick/ revert sequence; but
+        * first, make sure that an existing one isn't in
+        * progress
+        */
+
+       walk_revs_populate_todo(&todo_list, opts);
+       if (create_seq_dir() < 0)
+               return -1;
+       if (get_sha1("HEAD", sha1)) {
+               if (opts->action == REVERT)
+                       return error(_("Can't revert as initial commit"));
+               return error(_("Can't cherry-pick into empty head"));
+       }
+       save_head(sha1_to_hex(sha1));
+       save_opts(opts);
+       return pick_commits(todo_list, opts);
+}
+
 int cmd_revert(int argc, const char **argv, const char *prefix)
 {
+       struct replay_opts opts;
+       int res;
+
+       memset(&opts, 0, sizeof(opts));
        if (isatty(0))
-               edit = 1;
-       action = REVERT;
-       return revert_or_cherry_pick(argc, argv);
+               opts.edit = 1;
+       opts.action = REVERT;
+       git_config(git_default_config, NULL);
+       parse_args(argc, argv, &opts);
+       res = pick_revisions(&opts);
+       if (res < 0)
+               die(_("revert failed"));
+       return res;
 }
 
 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 {
-       action = CHERRY_PICK;
-       return revert_or_cherry_pick(argc, argv);
+       struct replay_opts opts;
+       int res;
+
+       memset(&opts, 0, sizeof(opts));
+       opts.action = CHERRY_PICK;
+       git_config(git_default_config, NULL);
+       parse_args(argc, argv, &opts);
+       res = pick_revisions(&opts);
+       if (res < 0)
+               die(_("cherry-pick failed"));
+       return res;
 }