1 files changed, 94 insertions, 66 deletions

diff --git a/builtin/merge.c b/builtin/merge.c
index f178f5a3ee..0f093f2a4f 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -313,8 +313,16 @@ static int save_state(struct object_id *stash)
 	int len;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf buffer = STRBUF_INIT;
+	struct lock_file lock_file = LOCK_INIT;
+	int fd;
 	int rc = -1;
 
+	fd = repo_hold_locked_index(the_repository, &lock_file, 0);
+	refresh_index(&the_index, REFRESH_QUIET, NULL, NULL, NULL);
+	if (0 <= fd)
+		repo_update_index_if_able(the_repository, &lock_file);
+	rollback_lock_file(&lock_file);
+
 	strvec_pushl(&cp.args, "stash", "create", NULL);
 	cp.out = -1;
 	cp.git_cmd = 1;
@@ -337,62 +345,54 @@ out:
 	return rc;
 }
 
-static void read_empty(const struct object_id *oid, int verbose)
+static void read_empty(const struct object_id *oid)
 {
-	int i = 0;
-	const char *args[7];
-
-	args[i++] = "read-tree";
-	if (verbose)
-		args[i++] = "-v";
-	args[i++] = "-m";
-	args[i++] = "-u";
-	args[i++] = empty_tree_oid_hex();
-	args[i++] = oid_to_hex(oid);
-	args[i] = NULL;
+	struct child_process cmd = CHILD_PROCESS_INIT;
+
+	strvec_pushl(&cmd.args, "read-tree", "-m", "-u", empty_tree_oid_hex(),
+		     oid_to_hex(oid), NULL);
+	cmd.git_cmd = 1;
 
-	if (run_command_v_opt(args, RUN_GIT_CMD))
+	if (run_command(&cmd))
 		die(_("read-tree failed"));
 }
 
-static void reset_hard(const struct object_id *oid, int verbose)
+static void reset_hard(const struct object_id *oid)
 {
-	int i = 0;
-	const char *args[6];
-
-	args[i++] = "read-tree";
-	if (verbose)
-		args[i++] = "-v";
-	args[i++] = "--reset";
-	args[i++] = "-u";
-	args[i++] = oid_to_hex(oid);
-	args[i] = NULL;
+	struct child_process cmd = CHILD_PROCESS_INIT;
+
+	strvec_pushl(&cmd.args, "read-tree", "-v", "--reset", "-u",
+		     oid_to_hex(oid), NULL);
+	cmd.git_cmd = 1;
 
-	if (run_command_v_opt(args, RUN_GIT_CMD))
+	if (run_command(&cmd))
 		die(_("read-tree failed"));
 }
 
 static void restore_state(const struct object_id *head,
 			  const struct object_id *stash)
 {
-	struct strbuf sb = STRBUF_INIT;
-	const char *args[] = { "stash", "apply", NULL, NULL };
+	struct child_process cmd = CHILD_PROCESS_INIT;
 
-	if (is_null_oid(stash))
-		return;
+	reset_hard(head);
 
-	reset_hard(head, 1);
+	if (is_null_oid(stash))
+		goto refresh_cache;
 
-	args[2] = oid_to_hex(stash);
+	strvec_pushl(&cmd.args, "stash", "apply", "--index", "--quiet", NULL);
+	strvec_push(&cmd.args, oid_to_hex(stash));
 
 	/*
 	 * It is OK to ignore error here, for example when there was
 	 * nothing to restore.
 	 */
-	run_command_v_opt(args, RUN_GIT_CMD);
+	cmd.git_cmd = 1;
+	run_command(&cmd);
 
-	strbuf_release(&sb);
-	refresh_cache(REFRESH_QUIET);
+refresh_cache:
+	discard_cache();
+	if (read_cache() < 0)
+		die(_("could not read index"));
 }
 
 /* This is called when no merge was necessary. */
@@ -443,6 +443,7 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
 	}
 	write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
 	strbuf_release(&out);
+	release_revisions(&rev);
 }
 
 static void finish(struct commit *head_commit,
@@ -492,7 +493,8 @@ static void finish(struct commit *head_commit,
 	/* Run a post-merge hook */
 	run_hooks_l("post-merge", squash ? "1" : "0", NULL);
 
-	apply_autostash(git_path_merge_autostash(the_repository));
+	if (new_head)
+		apply_autostash(git_path_merge_autostash(the_repository));
 	strbuf_release(&reflog_message);
 }
 
@@ -501,7 +503,6 @@ static void merge_name(const char *remote, struct strbuf *msg)
 {
 	struct commit *remote_head;
 	struct object_id branch_head;
-	struct strbuf buf = STRBUF_INIT;
 	struct strbuf bname = STRBUF_INIT;
 	struct merge_remote_desc *desc;
 	const char *ptr;
@@ -589,7 +590,6 @@ static void merge_name(const char *remote, struct strbuf *msg)
 		oid_to_hex(&remote_head->object.oid), remote);
 cleanup:
 	free(found_ref);
-	strbuf_release(&buf);
 	strbuf_release(&bname);
 }
 
@@ -694,7 +694,7 @@ static int read_tree_trivial(struct object_id *common, struct object_id *head,
 	if (!trees[nr_trees++])
 		return -1;
 	opts.fn = threeway_merge;
-	cache_tree_free(&active_cache_tree);
+	cache_tree_free(&the_index.cache_tree);
 	for (i = 0; i < nr_trees; i++) {
 		parse_tree(trees[i]);
 		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
@@ -716,7 +716,9 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 {
 	const char *head_arg = "HEAD";
 
-	if (refresh_and_write_cache(REFRESH_QUIET, SKIP_IF_UNCHANGED, 0) < 0)
+	if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET,
+					 SKIP_IF_UNCHANGED, 0, NULL, NULL,
+					 NULL) < 0)
 		return error(_("Unable to write index."));
 
 	if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree") ||
@@ -750,15 +752,18 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		for (j = common; j; j = j->next)
 			commit_list_insert(j->item, &reversed);
 
-		hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
+		repo_hold_locked_index(the_repository, &lock,
+				       LOCK_DIE_ON_ERROR);
 		if (!strcmp(strategy, "ort"))
 			clean = merge_ort_recursive(&o, head, remoteheads->item,
 						    reversed, &result);
 		else
 			clean = merge_recursive(&o, head, remoteheads->item,
 						reversed, &result);
-		if (clean < 0)
-			exit(128);
+		if (clean < 0) {
+			rollback_lock_file(&lock);
+			return 2;
+		}
 		if (write_locked_index(&the_index, &lock,
 				       COMMIT_LOCK | SKIP_IF_UNCHANGED))
 			die(_("unable to write %s"), get_index_file());
@@ -771,7 +776,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 }
 
 static void count_diff_files(struct diff_queue_struct *q,
-			     struct diff_options *opt, void *data)
+			     struct diff_options *opt UNUSED, void *data)
 {
 	int *count = data;
 
@@ -782,8 +787,8 @@ static int count_unmerged_entries(void)
 {
 	int i, ret = 0;
 
-	for (i = 0; i < active_nr; i++)
-		if (ce_stage(active_cache[i]))
+	for (i = 0; i < the_index.cache_nr; i++)
+		if (ce_stage(the_index.cache[i]))
 			ret++;
 
 	return ret;
@@ -857,9 +862,9 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 		 * the editor and after we invoke run_status above.
 		 */
 		if (invoked_hook)
-			discard_cache();
+			discard_index(&the_index);
 	}
-	read_cache_from(index_file);
+	read_index_from(&the_index, index_file, get_git_dir());
 	strbuf_addbuf(&msg, &merge_msg);
 	if (squash)
 		BUG("the control must not reach here under --squash");
@@ -908,7 +913,9 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 	struct object_id result_tree, result_commit;
 	struct commit_list *parents, **pptr = &parents;
 
-	if (refresh_and_write_cache(REFRESH_QUIET, SKIP_IF_UNCHANGED, 0) < 0)
+	if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET,
+					 SKIP_IF_UNCHANGED, 0, NULL, NULL,
+					 NULL) < 0)
 		return error(_("Unable to write index."));
 
 	write_tree_trivial(&result_tree);
@@ -998,6 +1005,7 @@ static int evaluate_result(void)
 	 */
 	cnt += count_unmerged_entries();
 
+	release_revisions(&rev);
 	return cnt;
 }
 
@@ -1373,7 +1381,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		goto done;
 	}
 
-	if (read_cache_unmerged())
+	if (repo_read_index_unmerged(the_repository))
 		die_resolve_conflict("merge");
 
 	if (file_exists(git_path_merge_head(the_repository))) {
@@ -1394,7 +1402,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		else
 			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
 	}
-	resolve_undo_clear();
+	resolve_undo_clear_index(&the_index);
 
 	if (option_edit < 0)
 		option_edit = default_edit_option();
@@ -1457,7 +1465,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 					       check_trust_level);
 
 		remote_head_oid = &remoteheads->item->object.oid;
-		read_empty(remote_head_oid, 0);
+		read_empty(remote_head_oid);
 		update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 		goto done;
@@ -1599,8 +1607,23 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		 * We are not doing octopus, not fast-forward, and have
 		 * only one common.
 		 */
-		refresh_cache(REFRESH_QUIET);
+		refresh_index(&the_index, REFRESH_QUIET, NULL, NULL, NULL);
 		if (allow_trivial && fast_forward != FF_ONLY) {
+			/*
+			 * Must first ensure that index matches HEAD before
+			 * attempting a trivial merge.
+			 */
+			struct tree *head_tree = get_commit_tree(head_commit);
+			struct strbuf sb = STRBUF_INIT;
+
+			if (repo_index_has_changes(the_repository, head_tree,
+						   &sb)) {
+				error(_("Your local changes to the following files would be overwritten by merge:\n  %s"),
+				      sb.buf);
+				strbuf_release(&sb);
+				return 2;
+			}
+
 			/* See if it is really trivial. */
 			git_committer_info(IDENT_STRICT);
 			printf(_("Trying really trivial in-index merge...\n"));
@@ -1657,15 +1680,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * tree in the index -- this means that the index must be in
 	 * sync with the head commit.  The strategies are responsible
 	 * to ensure this.
+	 *
+	 * Stash away the local changes so that we can try more than one
+	 * and/or recover from merge strategies bailing while leaving the
+	 * index and working tree polluted.
 	 */
-	if (use_strategies_nr == 1 ||
-	    /*
-	     * Stash away the local changes so that we can try more than one.
-	     */
-	    save_state(&stash))
+	if (save_state(&stash))
 		oidclr(&stash);
 
-	for (i = 0; !merge_was_ok && i < use_strategies_nr; i++) {
+	for (i = 0; i < use_strategies_nr; i++) {
 		int ret, cnt;
 		if (i) {
 			printf(_("Rewinding the tree to pristine...\n"));
@@ -1680,7 +1703,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		 */
 		wt_strategy = use_strategies[i]->name;
 
-		ret = try_merge_strategy(use_strategies[i]->name,
+		ret = try_merge_strategy(wt_strategy,
 					 common, remoteheads,
 					 head_commit);
 		/*
@@ -1690,16 +1713,17 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		 */
 		if (ret < 2) {
 			if (!ret) {
-				if (option_commit) {
-					/* Automerge succeeded. */
-					automerge_was_ok = 1;
-					break;
-				}
+				/*
+				 * This strategy worked; no point in trying
+				 * another.
+				 */
 				merge_was_ok = 1;
+				best_strategy = wt_strategy;
+				break;
 			}
 			cnt = (use_strategies_nr > 1) ? evaluate_result() : 0;
 			if (best_cnt <= 0 || cnt <= best_cnt) {
-				best_strategy = use_strategies[i]->name;
+				best_strategy = wt_strategy;
 				best_cnt = cnt;
 			}
 		}
@@ -1709,7 +1733,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * If we have a resulting tree, that means the strategy module
 	 * auto resolved the merge cleanly.
 	 */
-	if (automerge_was_ok) {
+	if (merge_was_ok && option_commit) {
+		automerge_was_ok = 1;
 		ret = finish_automerge(head_commit, head_subsumed,
 				       common, remoteheads,
 				       &result_tree, wt_strategy);
@@ -1754,6 +1779,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			"stopped before committing as requested\n"));
 	else
 		ret = suggest_conflicts();
+	if (autostash)
+		printf(_("When finished, apply stashed changes with `git stash pop`\n"));
 
 done:
 	if (!automerge_was_ok) {
@@ -1762,5 +1789,6 @@ done:
 	}
 	strbuf_release(&buf);
 	free(branch_to_free);
+	discard_index(&the_index);
 	return ret;
 }