Merge branch 'cc/reset-keep'

* cc/reset-keep:
  Documentation: improve description of "git reset --keep"
  reset: disallow using --keep when there are unmerged entries
  reset: disallow "reset --keep" outside a work tree
  Documentation: reset: describe new "--keep" option
  reset: add test cases for "--keep" option
  reset: add option "--keep" to "git reset"

1 files changed, 38 insertions, 9 deletions

diff --git a/builtin/reset.c b/builtin/reset.c
index 0f5022eed2..2c3a69adc6 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -22,13 +22,15 @@
 #include "cache-tree.h"
 
 static const char * const git_reset_usage[] = {
-	"git reset [--mixed | --soft | --hard | --merge] [-q] [<commit>]",
+	"git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]",
 	"git reset [--mixed] <commit> [--] <paths>...",
 	NULL
 };
 
-enum reset_type { MIXED, SOFT, HARD, MERGE, NONE };
-static const char *reset_type_names[] = { "mixed", "soft", "hard", "merge", NULL };
+enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };
+static const char *reset_type_names[] = {
+	"mixed", "soft", "hard", "merge", "keep", NULL
+};
 
 static char *args_to_str(const char **argv)
 {
@@ -71,6 +73,7 @@ static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet
 	if (!quiet)
 		opts.verbose_update = 1;
 	switch (reset_type) {
+	case KEEP:
 	case MERGE:
 		opts.update = 1;
 		break;
@@ -85,6 +88,16 @@ static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet
 
 	read_cache_unmerged();
 
+	if (reset_type == KEEP) {
+		unsigned char head_sha1[20];
+		if (get_sha1("HEAD", head_sha1))
+			return error("You do not have a valid HEAD.");
+		if (!fill_tree_descriptor(desc, head_sha1))
+			return error("Failed to find tree of HEAD.");
+		nr++;
+		opts.fn = twoway_merge;
+	}
+
 	if (!fill_tree_descriptor(desc + nr - 1, sha1))
 		return error("Failed to find tree of %s.", sha1_to_hex(sha1));
 	if (unpack_trees(nr, desc, &opts))
@@ -211,6 +224,14 @@ static void prepend_reflog_action(const char *action, char *buf, size_t size)
 		warning("Reflog action message too long: %.*s...", 50, buf);
 }
 
+static void die_if_unmerged_cache(int reset_type)
+{
+	if (is_merge() || read_cache() < 0 || unmerged_cache())
+		die("Cannot do a %s reset in the middle of a merge.",
+		    reset_type_names[reset_type]);
+
+}
+
 int cmd_reset(int argc, const char **argv, const char *prefix)
 {
 	int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
@@ -229,6 +250,8 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 				"reset HEAD, index and working tree", HARD),
 		OPT_SET_INT(0, "merge", &reset_type,
 				"reset HEAD, index and working tree", MERGE),
+		OPT_SET_INT(0, "keep", &reset_type,
+				"reset HEAD but keep local changes", KEEP),
 		OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 		OPT_END()
 	};
@@ -304,7 +327,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	if (reset_type == NONE)
 		reset_type = MIXED; /* by default */
 
-	if (reset_type == HARD || reset_type == MERGE)
+	if (reset_type != SOFT && reset_type != MIXED)
 		setup_work_tree();
 
 	if (reset_type == MIXED && is_bare_repository())
@@ -314,12 +337,18 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	/* Soft reset does not touch the index file nor the working tree
 	 * at all, but requires them in a good order.  Other resets reset
 	 * the index file to the tree object we are switching to. */
-	if (reset_type == SOFT) {
-		if (is_merge() || read_cache() < 0 || unmerged_cache())
-			die("Cannot do a soft reset in the middle of a merge.");
+	if (reset_type == SOFT)
+		die_if_unmerged_cache(reset_type);
+	else {
+		int err;
+		if (reset_type == KEEP)
+			die_if_unmerged_cache(reset_type);
+		err = reset_index_file(sha1, reset_type, quiet);
+		if (reset_type == KEEP)
+			err = err || reset_index_file(sha1, MIXED, quiet);
+		if (err)
+			die("Could not reset index file to revision '%s'.", rev);
 	}
-	else if (reset_index_file(sha1, reset_type, quiet))
-		die("Could not reset index file to revision '%s'.", rev);
 
 	/* Any resets update HEAD to the head being switched to,
 	 * saving the previous head in ORIG_HEAD before. */