1 files changed, 209 insertions, 110 deletions

diff --git a/builtin/revert.c b/builtin/revert.c
index eff52687a8..7976b5a329 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -13,6 +13,7 @@
 #include "revision.h"
 #include "rerere.h"
 #include "merge-recursive.h"
+#include "refs.h"
 
 /*
  * This implements the builtins revert and cherry-pick.
@@ -35,16 +36,19 @@ static const char * const cherry_pick_usage[] = {
 	NULL
 };
 
-static int edit, no_replay, no_commit, mainline, signoff;
+static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
 static enum { REVERT, CHERRY_PICK } action;
 static struct commit *commit;
 static const char *commit_name;
 static int allow_rerere_auto;
 
 static const char *me;
+static const char *strategy;
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
+static char *get_encoding(const char *message);
+
 static void parse_args(int argc, const char **argv)
 {
 	const char * const * usage_str =
@@ -59,9 +63,21 @@ static void parse_args(int argc, const char **argv)
 		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_END(),
+		OPT_END(),
 		OPT_END(),
 	};
 
+	if (action == CHERRY_PICK) {
+		struct option cp_extra[] = {
+			OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
+			OPT_END(),
+		};
+		if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
+			die("program error");
+	}
+
 	if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
 		usage_with_options(usage_str, options);
 
@@ -73,33 +89,69 @@ static void parse_args(int argc, const char **argv)
 		exit(1);
 }
 
-static char *get_oneline(const char *message)
+struct commit_message {
+	char *parent_label;
+	const char *label;
+	const char *subject;
+	char *reencoded_message;
+	const char *message;
+};
+
+static int get_message(const char *raw_message, struct commit_message *out)
 {
-	char *result;
-	const char *p = message, *abbrev, *eol;
+	const char *encoding;
+	const char *p, *abbrev, *eol;
+	char *q;
 	int abbrev_len, oneline_len;
 
-	if (!p)
-		die ("Could not read commit message of %s",
-				sha1_to_hex(commit->object.sha1));
+	if (!raw_message)
+		return -1;
+	encoding = get_encoding(raw_message);
+	if (!encoding)
+		encoding = "UTF-8";
+	if (!git_commit_encoding)
+		git_commit_encoding = "UTF-8";
+
+	out->reencoded_message = NULL;
+	out->message = raw_message;
+	if (strcmp(encoding, git_commit_encoding))
+		out->reencoded_message = reencode_string(raw_message,
+					git_commit_encoding, encoding);
+	if (out->reencoded_message)
+		out->message = out->reencoded_message;
+
+	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
+	abbrev_len = strlen(abbrev);
+
+	/* Find beginning and end of commit subject. */
+	p = out->message;
 	while (*p && (*p != '\n' || p[1] != '\n'))
 		p++;
-
 	if (*p) {
 		p += 2;
 		for (eol = p + 1; *eol && *eol != '\n'; eol++)
 			; /* do nothing */
 	} else
 		eol = p;
-	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
-	abbrev_len = strlen(abbrev);
 	oneline_len = eol - p;
-	result = xmalloc(abbrev_len + 5 + oneline_len);
-	memcpy(result, abbrev, abbrev_len);
-	memcpy(result + abbrev_len, "... ", 4);
-	memcpy(result + abbrev_len + 4, p, oneline_len);
-	result[abbrev_len + 4 + oneline_len] = '\0';
-	return result;
+
+	out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
+			      strlen("... ") + oneline_len + 1);
+	q = out->parent_label;
+	q = mempcpy(q, "parent of ", strlen("parent of "));
+	out->label = q;
+	q = mempcpy(q, abbrev, abbrev_len);
+	q = mempcpy(q, "... ", strlen("... "));
+	out->subject = q;
+	q = mempcpy(q, p, oneline_len);
+	*q = '\0';
+	return 0;
+}
+
+static void free_message(struct commit_message *msg)
+{
+	free(msg->parent_label);
+	free(msg->reencoded_message);
 }
 
 static char *get_encoding(const char *message)
@@ -124,28 +176,17 @@ static char *get_encoding(const char *message)
 	return NULL;
 }
 
-static struct lock_file msg_file;
-static int msg_fd;
-
-static void add_to_msg(const char *string)
-{
-	int len = strlen(string);
-	if (write_in_full(msg_fd, string, len) < 0)
-		die_errno ("Could not write to MERGE_MSG");
-}
-
-static void add_message_to_msg(const char *message)
+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)
-		add_to_msg(sha1_to_hex(commit->object.sha1));
+		strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 
 	p += 2;
-	add_to_msg(p);
-	return;
+	strbuf_addstr(msgbuf, p);
 }
 
 static void set_author_ident_env(const char *message)
@@ -221,6 +262,19 @@ static char *help_msg(const char *name)
 	return strbuf_detach(&helpbuf, NULL);
 }
 
+static void write_message(struct strbuf *msgbuf, const char *filename)
+{
+	static struct lock_file msg_file;
+
+	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);
+	strbuf_release(msgbuf);
+	if (commit_lock_file(&msg_file) < 0)
+		die("Error wrapping up %s", filename);
+}
+
 static struct tree *empty_tree(void)
 {
 	struct tree *tree = xcalloc(1, sizeof(struct tree));
@@ -244,18 +298,82 @@ static NORETURN void die_dirty_index(const char *me)
 	}
 }
 
-static int revert_or_cherry_pick(int argc, const char **argv)
+static int fast_forward_to(const unsigned char *to, const unsigned char *from)
+{
+	struct ref_lock *ref_lock;
+
+	read_cache();
+	if (checkout_fast_forward(from, to))
+		exit(1); /* the callee should have complained already */
+	ref_lock = lock_any_ref_for_update("HEAD", from, 0);
+	return write_ref_sha1(ref_lock, to, "cherry-pick");
+}
+
+static void do_recursive_merge(struct commit *base, struct commit *next,
+			       const char *base_label, const char *next_label,
+			       unsigned char *head, struct strbuf *msgbuf,
+			       char *defmsg)
 {
-	unsigned char head[20];
-	struct commit *base, *next, *parent;
-	int i, index_fd, clean;
-	char *oneline, *reencoded_message = NULL;
-	const char *message, *encoding;
-	char *defmsg = git_pathdup("MERGE_MSG");
 	struct merge_options o;
 	struct tree *result, *next_tree, *base_tree, *head_tree;
+	int clean, index_fd;
 	static struct lock_file index_lock;
 
+	index_fd = hold_locked_index(&index_lock, 1);
+
+	read_cache();
+	init_merge_options(&o);
+	o.ancestor = base ? base_label : "(empty tree)";
+	o.branch1 = "HEAD";
+	o.branch2 = next ? next_label : "(empty tree)";
+
+	head_tree = parse_tree_indirect(head);
+	next_tree = next ? next->tree : empty_tree();
+	base_tree = base ? base->tree : empty_tree();
+
+	clean = merge_trees(&o,
+			    head_tree,
+			    next_tree, base_tree, &result);
+
+	if (active_cache_changed &&
+	    (write_cache(index_fd, active_cache, active_nr) ||
+	     commit_locked_index(&index_lock)))
+		die("%s: Unable to write new index file", me);
+	rollback_lock_file(&index_lock);
+
+	if (!clean) {
+		int i;
+		strbuf_addstr(msgbuf, "\nConflicts:\n\n");
+		for (i = 0; i < active_nr;) {
+			struct cache_entry *ce = active_cache[i++];
+			if (ce_stage(ce)) {
+				strbuf_addch(msgbuf, '\t');
+				strbuf_addstr(msgbuf, ce->name);
+				strbuf_addch(msgbuf, '\n');
+				while (i < active_nr && !strcmp(ce->name,
+						active_cache[i]->name))
+					i++;
+			}
+		}
+		write_message(msgbuf, defmsg);
+		fprintf(stderr, "Automatic %s failed.%s\n",
+			me, help_msg(commit_name));
+		rerere(allow_rerere_auto);
+		exit(1);
+	}
+	write_message(msgbuf, defmsg);
+	fprintf(stderr, "Finished one %s.\n", me);
+}
+
+static int revert_or_cherry_pick(int argc, const char **argv)
+{
+	unsigned char head[20];
+	struct commit *base, *next, *parent;
+	const char *base_label, *next_label;
+	struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
+	char *defmsg = NULL;
+	struct strbuf msgbuf = STRBUF_INIT;
+
 	git_config(git_default_config, NULL);
 	me = action == REVERT ? "revert" : "cherry-pick";
 	setenv(GIT_REFLOG_ACTION, me, 0);
@@ -265,6 +383,17 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	if (action == REVERT && !no_replay)
 		die("revert is incompatible with replay");
 
+	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");
+	}
+
 	if (read_cache() < 0)
 		die("git %s: failed to read the index", me);
 	if (no_commit) {
@@ -284,8 +413,6 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	}
 	discard_cache();
 
-	index_fd = hold_locked_index(&index_lock, 1);
-
 	if (!commit->parents) {
 		if (action == REVERT)
 			die ("Cannot revert a root commit");
@@ -314,14 +441,17 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	else
 		parent = commit->parents->item;
 
-	if (!(message = commit->buffer))
-		die ("Cannot get commit message for %s",
-				sha1_to_hex(commit->object.sha1));
+	if (allow_ff && !hashcmp(parent->object.sha1, head))
+		return fast_forward_to(commit->object.sha1, head);
 
 	if (parent && parse_commit(parent) < 0)
 		die("%s: cannot parse parent commit %s",
 		    me, 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));
+
 	/*
 	 * "commit" is an existing commit.  We would want to apply
 	 * the difference it introduces since its first parent "prev"
@@ -329,89 +459,58 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	 * reverse of it if we are revert.
 	 */
 
-	msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
-					   LOCK_DIE_ON_ERROR);
-
-	encoding = get_encoding(message);
-	if (!encoding)
-		encoding = "UTF-8";
-	if (!git_commit_encoding)
-		git_commit_encoding = "UTF-8";
-	if ((reencoded_message = reencode_string(message,
-					git_commit_encoding, encoding)))
-		message = reencoded_message;
-
-	oneline = get_oneline(message);
+	defmsg = git_pathdup("MERGE_MSG");
 
 	if (action == REVERT) {
-		char *oneline_body = strchr(oneline, ' ');
-
 		base = commit;
+		base_label = msg.label;
 		next = parent;
-		add_to_msg("Revert \"");
-		add_to_msg(oneline_body + 1);
-		add_to_msg("\"\n\nThis reverts commit ");
-		add_to_msg(sha1_to_hex(commit->object.sha1));
+		next_label = msg.parent_label;
+		strbuf_addstr(&msgbuf, "Revert \"");
+		strbuf_addstr(&msgbuf, msg.subject);
+		strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
+		strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 
 		if (commit->parents->next) {
-			add_to_msg(", reversing\nchanges made to ");
-			add_to_msg(sha1_to_hex(parent->object.sha1));
+			strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
+			strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 		}
-		add_to_msg(".\n");
+		strbuf_addstr(&msgbuf, ".\n");
 	} else {
 		base = parent;
+		base_label = msg.parent_label;
 		next = commit;
-		set_author_ident_env(message);
-		add_message_to_msg(message);
+		next_label = msg.label;
+		set_author_ident_env(msg.message);
+		add_message_to_msg(&msgbuf, msg.message);
 		if (no_replay) {
-			add_to_msg("(cherry picked from commit ");
-			add_to_msg(sha1_to_hex(commit->object.sha1));
-			add_to_msg(")\n");
+			strbuf_addstr(&msgbuf, "(cherry picked from commit ");
+			strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
+			strbuf_addstr(&msgbuf, ")\n");
 		}
 	}
 
-	read_cache();
-	init_merge_options(&o);
-	o.branch1 = "HEAD";
-	o.branch2 = oneline;
-
-	head_tree = parse_tree_indirect(head);
-	next_tree = next ? next->tree : empty_tree();
-	base_tree = base ? base->tree : empty_tree();
-
-	clean = merge_trees(&o,
-			    head_tree,
-			    next_tree, base_tree, &result);
-
-	if (active_cache_changed &&
-	    (write_cache(index_fd, active_cache, active_nr) ||
-	     commit_locked_index(&index_lock)))
-		die("%s: Unable to write new index file", me);
-	rollback_lock_file(&index_lock);
-
-	if (!clean) {
-		add_to_msg("\nConflicts:\n\n");
-		for (i = 0; i < active_nr;) {
-			struct cache_entry *ce = active_cache[i++];
-			if (ce_stage(ce)) {
-				add_to_msg("\t");
-				add_to_msg(ce->name);
-				add_to_msg("\n");
-				while (i < active_nr && !strcmp(ce->name,
-						active_cache[i]->name))
-					i++;
-			}
+	if (!strategy || !strcmp(strategy, "recursive") || action == REVERT)
+		do_recursive_merge(base, next, base_label, next_label,
+				   head, &msgbuf, defmsg);
+	else {
+		int res;
+		struct commit_list *common = NULL;
+		struct commit_list *remotes = NULL;
+		write_message(&msgbuf, defmsg);
+		commit_list_insert(base, &common);
+		commit_list_insert(next, &remotes);
+		res = try_merge_command(strategy, common,
+					sha1_to_hex(head), remotes);
+		free_commit_list(common);
+		free_commit_list(remotes);
+		if (res) {
+			fprintf(stderr, "Automatic %s with strategy %s failed.%s\n",
+				me, strategy, help_msg(commit_name));
+			rerere(allow_rerere_auto);
+			exit(1);
 		}
-		if (commit_lock_file(&msg_file) < 0)
-			die ("Error wrapping up %s", defmsg);
-		fprintf(stderr, "Automatic %s failed.%s\n",
-			me, help_msg(commit_name));
-		rerere(allow_rerere_auto);
-		exit(1);
 	}
-	if (commit_lock_file(&msg_file) < 0)
-		die ("Error wrapping up %s", defmsg);
-	fprintf(stderr, "Finished one %s.\n", me);
 
 	/*
 	 *
@@ -437,7 +536,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		args[i] = NULL;
 		return execv_git_cmd(args);
 	}
-	free(reencoded_message);
+	free_message(&msg);
 	free(defmsg);
 
 	return 0;