1 files changed, 92 insertions, 79 deletions

diff --git a/builtin-revert.c b/builtin-revert.c
index 27881e9493..eff52687a8 100644
--- a/builtin-revert.c
+++ b/builtin-revert.c
@@ -11,6 +11,8 @@
 #include "cache-tree.h"
 #include "diff.h"
 #include "revision.h"
+#include "rerere.h"
+#include "merge-recursive.h"
 
 /*
  * This implements the builtins revert and cherry-pick.
@@ -36,6 +38,8 @@ static const char * const cherry_pick_usage[] = {
 static int edit, no_replay, no_commit, mainline, signoff;
 static enum { REVERT, CHERRY_PICK } action;
 static struct commit *commit;
+static const char *commit_name;
+static int allow_rerere_auto;
 
 static const char *me;
 
@@ -46,7 +50,6 @@ static void parse_args(int argc, const char **argv)
 	const char * const * usage_str =
 		action == REVERT ?  revert_usage : cherry_pick_usage;
 	unsigned char sha1[20];
-	const char *arg;
 	int noop;
 	struct option options[] = {
 		OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
@@ -55,24 +58,19 @@ static void parse_args(int argc, const char **argv)
 		OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
 		OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
 		OPT_INTEGER('m', "mainline", &mainline, "parent number"),
+		OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 		OPT_END(),
 	};
 
-	if (parse_options(argc, argv, options, usage_str, 0) != 1)
+	if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
 		usage_with_options(usage_str, options);
-	arg = argv[0];
 
-	if (get_sha1(arg, sha1))
-		die ("Cannot find '%s'", arg);
-	commit = (struct commit *)parse_object(sha1);
+	commit_name = argv[0];
+	if (get_sha1(commit_name, sha1))
+		die ("Cannot find '%s'", commit_name);
+	commit = lookup_commit_reference(sha1);
 	if (!commit)
-		die ("Could not find %s", sha1_to_hex(sha1));
-	if (commit->object.type == OBJ_TAG) {
-		commit = (struct commit *)
-			deref_tag((struct object *)commit, arg, strlen(arg));
-	}
-	if (commit->object.type != OBJ_COMMIT)
-		die ("'%s' does not point to a commit", arg);
+		exit(1);
 }
 
 static char *get_oneline(const char *message)
@@ -133,7 +131,7 @@ static void add_to_msg(const char *string)
 {
 	int len = strlen(string);
 	if (write_in_full(msg_fd, string, len) < 0)
-		die ("Could not write to MERGE_MSG");
+		die_errno ("Could not write to MERGE_MSG");
 }
 
 static void add_message_to_msg(const char *message)
@@ -200,76 +198,63 @@ static void set_author_ident_env(const char *message)
 			sha1_to_hex(commit->object.sha1));
 }
 
-static int merge_recursive(const char *base_sha1,
-		const char *head_sha1, const char *head_name,
-		const char *next_sha1, const char *next_name)
-{
-	char buffer[256];
-	const char *argv[6];
-	int i = 0;
-
-	sprintf(buffer, "GITHEAD_%s", head_sha1);
-	setenv(buffer, head_name, 1);
-	sprintf(buffer, "GITHEAD_%s", next_sha1);
-	setenv(buffer, next_name, 1);
-
-	/*
-	 * This three way merge is an interesting one.  We are at
-	 * $head, and would want to apply the change between $commit
-	 * and $prev on top of us (when reverting), or the change between
-	 * $prev and $commit on top of us (when cherry-picking or replaying).
-	 */
-	argv[i++] = "merge-recursive";
-	if (base_sha1)
-		argv[i++] = base_sha1;
-	argv[i++] = "--";
-	argv[i++] = head_sha1;
-	argv[i++] = next_sha1;
-	argv[i++] = NULL;
-
-	return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
-}
-
-static char *help_msg(const unsigned char *sha1)
+static char *help_msg(const char *name)
 {
-	static char helpbuf[1024];
+	struct strbuf helpbuf = STRBUF_INIT;
 	char *msg = getenv("GIT_CHERRY_PICK_HELP");
 
 	if (msg)
 		return msg;
 
-	strcpy(helpbuf, "  After resolving the conflicts,\n"
-	       "mark the corrected paths with 'git add <paths>' "
-	       "or 'git rm <paths>' and commit the result.");
+	strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
+		"mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
+		"and commit the result");
 
 	if (action == CHERRY_PICK) {
-		sprintf(helpbuf + strlen(helpbuf),
-			"\nWhen commiting, use the option "
-			"'-c %s' to retain authorship and message.",
-			find_unique_abbrev(sha1, DEFAULT_ABBREV));
+		strbuf_addf(&helpbuf, " with: \n"
+			"\n"
+			"        git commit -c %s\n",
+			name);
 	}
-	return helpbuf;
+	else
+		strbuf_addch(&helpbuf, '.');
+	return strbuf_detach(&helpbuf, NULL);
+}
+
+static struct tree *empty_tree(void)
+{
+	struct tree *tree = xcalloc(1, sizeof(struct tree));
+
+	tree->object.parsed = 1;
+	tree->object.type = OBJ_TREE;
+	pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
+	return tree;
 }
 
-static int index_is_dirty(void)
+static NORETURN void die_dirty_index(const char *me)
 {
-	struct rev_info rev;
-	init_revisions(&rev, NULL);
-	setup_revisions(0, NULL, &rev, "HEAD");
-	DIFF_OPT_SET(&rev.diffopt, QUIET);
-	DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
-	run_diff_index(&rev, 1);
-	return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
+	if (read_cache_unmerged()) {
+		die_resolve_conflict(me);
+	} else {
+		if (advice_commit_before_merge)
+			die("Your local changes would be overwritten by %s.\n"
+			    "Please, commit your changes or stash them to proceed.", me);
+		else
+			die("Your local changes would be overwritten by %s.\n", me);
+	}
 }
 
 static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
-	int i;
+	int i, index_fd, clean;
 	char *oneline, *reencoded_message = NULL;
 	const char *message, *encoding;
-	const char *defmsg = xstrdup(git_path("MERGE_MSG"));
+	char *defmsg = git_pathdup("MERGE_MSG");
+	struct merge_options o;
+	struct tree *result, *next_tree, *base_tree, *head_tree;
+	static struct lock_file index_lock;
 
 	git_config(git_default_config, NULL);
 	me = action == REVERT ? "revert" : "cherry-pick";
@@ -280,6 +265,8 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	if (action == REVERT && !no_replay)
 		die("revert is incompatible with replay");
 
+	if (read_cache() < 0)
+		die("git %s: failed to read the index", me);
 	if (no_commit) {
 		/*
 		 * We do not intend to commit immediately.  We just want to
@@ -292,12 +279,12 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	} else {
 		if (get_sha1("HEAD", head))
 			die ("You do not have a valid HEAD");
-		if (read_cache() < 0)
-			die("could not read the index");
-		if (index_is_dirty())
-			die ("Dirty index: cannot %s", me);
-		discard_cache();
+		if (index_differs_from("HEAD", 0))
+			die_dirty_index(me);
 	}
+	discard_cache();
+
+	index_fd = hold_locked_index(&index_lock, 1);
 
 	if (!commit->parents) {
 		if (action == REVERT)
@@ -331,6 +318,10 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		die ("Cannot get commit message for %s",
 				sha1_to_hex(commit->object.sha1));
 
+	if (parent && parse_commit(parent) < 0)
+		die("%s: cannot parse parent commit %s",
+		    me, sha1_to_hex(parent->object.sha1));
+
 	/*
 	 * "commit" is an existing commit.  We would want to apply
 	 * the difference it introduces since its first parent "prev"
@@ -338,13 +329,14 @@ 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, 1);
+	msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
+					   LOCK_DIE_ON_ERROR);
 
 	encoding = get_encoding(message);
 	if (!encoding)
-		encoding = "utf-8";
+		encoding = "UTF-8";
 	if (!git_commit_encoding)
-		git_commit_encoding = "utf-8";
+		git_commit_encoding = "UTF-8";
 	if ((reencoded_message = reencode_string(message,
 					git_commit_encoding, encoding)))
 		message = reencoded_message;
@@ -360,6 +352,11 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		add_to_msg(oneline_body + 1);
 		add_to_msg("\"\n\nThis reverts commit ");
 		add_to_msg(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));
+		}
 		add_to_msg(".\n");
 	} else {
 		base = parent;
@@ -373,13 +370,27 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		}
 	}
 
-	if (merge_recursive(base == NULL ?
-				NULL : sha1_to_hex(base->object.sha1),
-				sha1_to_hex(head), "HEAD",
-				sha1_to_hex(next->object.sha1), oneline) ||
-			write_cache_as_tree(head, 0, NULL)) {
+	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");
-		read_cache();
 		for (i = 0; i < active_nr;) {
 			struct cache_entry *ce = active_cache[i++];
 			if (ce_stage(ce)) {
@@ -394,7 +405,8 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		if (commit_lock_file(&msg_file) < 0)
 			die ("Error wrapping up %s", defmsg);
 		fprintf(stderr, "Automatic %s failed.%s\n",
-			me, help_msg(commit->object.sha1));
+			me, help_msg(commit_name));
+		rerere(allow_rerere_auto);
 		exit(1);
 	}
 	if (commit_lock_file(&msg_file) < 0)
@@ -426,6 +438,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		return execv_git_cmd(args);
 	}
 	free(reencoded_message);
+	free(defmsg);
 
 	return 0;
 }