1 files changed, 472 insertions, 42 deletions

diff --git a/submodule.c b/submodule.c
index e9f2b19e1..2f5543623 100644
--- a/submodule.c
+++ b/submodule.c
@@ -8,11 +8,27 @@
 #include "diffcore.h"
 #include "refs.h"
 #include "string-list.h"
-
-struct string_list config_name_for_path;
-struct string_list config_fetch_recurse_submodules_for_name;
-struct string_list config_ignore_for_name;
-static int config_fetch_recurse_submodules;
+#include "sha1-array.h"
+#include "argv-array.h"
+
+static struct string_list config_name_for_path;
+static struct string_list config_fetch_recurse_submodules_for_name;
+static struct string_list config_ignore_for_name;
+static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
+static struct string_list changed_submodule_paths;
+static int initialized_fetch_ref_tips;
+static struct sha1_array ref_tips_before_fetch;
+static struct sha1_array ref_tips_after_fetch;
+
+/*
+ * The following flag is set if the .gitmodules file is unmerged. We then
+ * disable recursion for all submodules where .git/config doesn't have a
+ * matching config entry because we can't guess what might be configured in
+ * .gitmodules unless the user resolves the conflict. When a command line
+ * option is given (which always overrides configuration) this flag will be
+ * ignored.
+ */
+static int gitmodules_is_unmerged;
 
 static int add_submodule_odb(const char *path)
 {
@@ -22,7 +38,7 @@ static int add_submodule_odb(const char *path)
 	const char *git_dir;
 
 	strbuf_addf(&objects_directory, "%s/.git", path);
-	git_dir = read_gitfile_gently(objects_directory.buf);
+	git_dir = read_gitfile(objects_directory.buf);
 	if (git_dir) {
 		strbuf_reset(&objects_directory);
 		strbuf_addstr(&objects_directory, git_dir);
@@ -47,6 +63,9 @@ static int add_submodule_odb(const char *path)
 	alt_odb->name[40] = '\0';
 	alt_odb->name[41] = '\0';
 	alt_odb_list = alt_odb;
+
+	/* add possible alternates from the submodule */
+	read_info_alternates(objects_directory.buf, 0);
 	prepare_alt_odb();
 done:
 	strbuf_release(&objects_directory);
@@ -62,6 +81,8 @@ void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 		ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, path_option->util);
 		if (ignore_option)
 			handle_ignore_submodules_arg(diffopt, ignore_option->util);
+		else if (gitmodules_is_unmerged)
+			DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 	}
 }
 
@@ -70,7 +91,7 @@ int submodule_config(const char *var, const char *value, void *cb)
 	if (!prefixcmp(var, "submodule."))
 		return parse_submodule_config_option(var, value);
 	else if (!strcmp(var, "fetch.recursesubmodules")) {
-		config_fetch_recurse_submodules = git_config_bool(var, value);
+		config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
 		return 0;
 	}
 	return 0;
@@ -81,9 +102,24 @@ void gitmodules_config(void)
 	const char *work_tree = get_git_work_tree();
 	if (work_tree) {
 		struct strbuf gitmodules_path = STRBUF_INIT;
+		int pos;
 		strbuf_addstr(&gitmodules_path, work_tree);
 		strbuf_addstr(&gitmodules_path, "/.gitmodules");
-		git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
+		if (read_cache() < 0)
+			die("index file corrupt");
+		pos = cache_name_pos(".gitmodules", 11);
+		if (pos < 0) { /* .gitmodules not found or isn't merged */
+			pos = -1 - pos;
+			if (active_nr > pos) {  /* there is a .gitmodules */
+				const struct cache_entry *ce = active_cache[pos];
+				if (ce_namelen(ce) == 11 &&
+				    !memcmp(ce->name, ".gitmodules", 11))
+					gitmodules_is_unmerged = 1;
+			}
+		}
+
+		if (!gitmodules_is_unmerged)
+			git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
 		strbuf_release(&gitmodules_path);
 	}
 }
@@ -112,7 +148,7 @@ int parse_submodule_config_option(const char *var, const char *value)
 		if (!config)
 			config = string_list_append(&config_fetch_recurse_submodules_for_name,
 						    strbuf_detach(&submodname, NULL));
-		config->util = git_config_bool(var, value) ? (void *)1 : NULL;
+		config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
 		strbuf_release(&submodname);
 	} else if ((len > 7) && !strcmp(var + len - 7, ".ignore")) {
 		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
@@ -206,9 +242,23 @@ static void print_submodule_summary(struct rev_info *rev, FILE *f,
 	strbuf_release(&sb);
 }
 
+int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
+{
+	switch (git_config_maybe_bool(opt, arg)) {
+	case 1:
+		return RECURSE_SUBMODULES_ON;
+	case 0:
+		return RECURSE_SUBMODULES_OFF;
+	default:
+		if (!strcmp(arg, "on-demand"))
+			return RECURSE_SUBMODULES_ON_DEMAND;
+		die("bad %s argument: %s", opt, arg);
+	}
+}
+
 void show_submodule_summary(FILE *f, const char *path,
 		unsigned char one[20], unsigned char two[20],
-		unsigned dirty_submodule,
+		unsigned dirty_submodule, const char *meta,
 		const char *del, const char *add, const char *reset)
 {
 	struct rev_info rev;
@@ -242,15 +292,15 @@ void show_submodule_summary(FILE *f, const char *path,
 		return;
 	}
 
-	strbuf_addf(&sb, "Submodule %s %s..", path,
+	strbuf_addf(&sb, "%sSubmodule %s %s..", meta, path,
 			find_unique_abbrev(one, DEFAULT_ABBREV));
 	if (!fast_backward && !fast_forward)
 		strbuf_addch(&sb, '.');
 	strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
 	if (message)
-		strbuf_addf(&sb, " %s\n", message);
+		strbuf_addf(&sb, " %s%s\n", message, reset);
 	else
-		strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
+		strbuf_addf(&sb, "%s:%s\n", fast_backward ? " (rewind)" : "", reset);
 	fwrite(sb.buf, sb.len, 1, f);
 
 	if (!message) {
@@ -267,41 +317,312 @@ void set_config_fetch_recurse_submodules(int value)
 	config_fetch_recurse_submodules = value;
 }
 
-int fetch_populated_submodules(int num_options, const char **options,
-			       const char *prefix, int ignore_config,
+static int has_remote(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
+{
+	return 1;
+}
+
+static int submodule_needs_pushing(const char *path, const unsigned char sha1[20])
+{
+	if (add_submodule_odb(path) || !lookup_commit_reference(sha1))
+		return 0;
+
+	if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
+		struct child_process cp;
+		const char *argv[] = {"rev-list", NULL, "--not", "--remotes", "-n", "1" , NULL};
+		struct strbuf buf = STRBUF_INIT;
+		int needs_pushing = 0;
+
+		argv[1] = sha1_to_hex(sha1);
+		memset(&cp, 0, sizeof(cp));
+		cp.argv = argv;
+		cp.env = local_repo_env;
+		cp.git_cmd = 1;
+		cp.no_stdin = 1;
+		cp.out = -1;
+		cp.dir = path;
+		if (start_command(&cp))
+			die("Could not run 'git rev-list %s --not --remotes -n 1' command in submodule %s",
+				sha1_to_hex(sha1), path);
+		if (strbuf_read(&buf, cp.out, 41))
+			needs_pushing = 1;
+		finish_command(&cp);
+		close(cp.out);
+		strbuf_release(&buf);
+		return needs_pushing;
+	}
+
+	return 0;
+}
+
+static void collect_submodules_from_diff(struct diff_queue_struct *q,
+					 struct diff_options *options,
+					 void *data)
+{
+	int i;
+	struct string_list *needs_pushing = data;
+
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+		if (!S_ISGITLINK(p->two->mode))
+			continue;
+		if (submodule_needs_pushing(p->two->path, p->two->sha1))
+			string_list_insert(needs_pushing, p->two->path);
+	}
+}
+
+static void find_unpushed_submodule_commits(struct commit *commit,
+		struct string_list *needs_pushing)
+{
+	struct rev_info rev;
+
+	init_revisions(&rev, NULL);
+	rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
+	rev.diffopt.format_callback = collect_submodules_from_diff;
+	rev.diffopt.format_callback_data = needs_pushing;
+	diff_tree_combined_merge(commit, 1, &rev);
+}
+
+int find_unpushed_submodules(unsigned char new_sha1[20],
+		const char *remotes_name, struct string_list *needs_pushing)
+{
+	struct rev_info rev;
+	struct commit *commit;
+	const char *argv[] = {NULL, NULL, "--not", "NULL", NULL};
+	int argc = ARRAY_SIZE(argv) - 1;
+	char *sha1_copy;
+
+	struct strbuf remotes_arg = STRBUF_INIT;
+
+	strbuf_addf(&remotes_arg, "--remotes=%s", remotes_name);
+	init_revisions(&rev, NULL);
+	sha1_copy = xstrdup(sha1_to_hex(new_sha1));
+	argv[1] = sha1_copy;
+	argv[3] = remotes_arg.buf;
+	setup_revisions(argc, argv, &rev, NULL);
+	if (prepare_revision_walk(&rev))
+		die("revision walk setup failed");
+
+	while ((commit = get_revision(&rev)) != NULL)
+		find_unpushed_submodule_commits(commit, needs_pushing);
+
+	reset_revision_walk();
+	free(sha1_copy);
+	strbuf_release(&remotes_arg);
+
+	return needs_pushing->nr;
+}
+
+static int push_submodule(const char *path)
+{
+	if (add_submodule_odb(path))
+		return 1;
+
+	if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
+		struct child_process cp;
+		const char *argv[] = {"push", NULL};
+
+		memset(&cp, 0, sizeof(cp));
+		cp.argv = argv;
+		cp.env = local_repo_env;
+		cp.git_cmd = 1;
+		cp.no_stdin = 1;
+		cp.dir = path;
+		if (run_command(&cp))
+			return 0;
+		close(cp.out);
+	}
+
+	return 1;
+}
+
+int push_unpushed_submodules(unsigned char new_sha1[20], const char *remotes_name)
+{
+	int i, ret = 1;
+	struct string_list needs_pushing;
+
+	memset(&needs_pushing, 0, sizeof(struct string_list));
+	needs_pushing.strdup_strings = 1;
+
+	if (!find_unpushed_submodules(new_sha1, remotes_name, &needs_pushing))
+		return 1;
+
+	for (i = 0; i < needs_pushing.nr; i++) {
+		const char *path = needs_pushing.items[i].string;
+		fprintf(stderr, "Pushing submodule '%s'\n", path);
+		if (!push_submodule(path)) {
+			fprintf(stderr, "Unable to push submodule '%s'\n", path);
+			ret = 0;
+		}
+	}
+
+	string_list_clear(&needs_pushing, 0);
+
+	return ret;
+}
+
+static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
+{
+	int is_present = 0;
+	if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
+		/* Even if the submodule is checked out and the commit is
+		 * present, make sure it is reachable from a ref. */
+		struct child_process cp;
+		const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
+		struct strbuf buf = STRBUF_INIT;
+
+		argv[3] = sha1_to_hex(sha1);
+		memset(&cp, 0, sizeof(cp));
+		cp.argv = argv;
+		cp.env = local_repo_env;
+		cp.git_cmd = 1;
+		cp.no_stdin = 1;
+		cp.out = -1;
+		cp.dir = path;
+		if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
+			is_present = 1;
+
+		close(cp.out);
+		strbuf_release(&buf);
+	}
+	return is_present;
+}
+
+static void submodule_collect_changed_cb(struct diff_queue_struct *q,
+					 struct diff_options *options,
+					 void *data)
+{
+	int i;
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+		if (!S_ISGITLINK(p->two->mode))
+			continue;
+
+		if (S_ISGITLINK(p->one->mode)) {
+			/* NEEDSWORK: We should honor the name configured in
+			 * the .gitmodules file of the commit we are examining
+			 * here to be able to correctly follow submodules
+			 * being moved around. */
+			struct string_list_item *path;
+			path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
+			if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
+				string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
+		} else {
+			/* Submodule is new or was moved here */
+			/* NEEDSWORK: When the .git directories of submodules
+			 * live inside the superprojects .git directory some
+			 * day we should fetch new submodules directly into
+			 * that location too when config or options request
+			 * that so they can be checked out from there. */
+			continue;
+		}
+	}
+}
+
+static int add_sha1_to_array(const char *ref, const unsigned char *sha1,
+			     int flags, void *data)
+{
+	sha1_array_append(data, sha1);
+	return 0;
+}
+
+void check_for_new_submodule_commits(unsigned char new_sha1[20])
+{
+	if (!initialized_fetch_ref_tips) {
+		for_each_ref(add_sha1_to_array, &ref_tips_before_fetch);
+		initialized_fetch_ref_tips = 1;
+	}
+
+	sha1_array_append(&ref_tips_after_fetch, new_sha1);
+}
+
+static void add_sha1_to_argv(const unsigned char sha1[20], void *data)
+{
+	argv_array_push(data, sha1_to_hex(sha1));
+}
+
+static void calculate_changed_submodule_paths(void)
+{
+	struct rev_info rev;
+	struct commit *commit;
+	struct argv_array argv = ARGV_ARRAY_INIT;
+
+	/* No need to check if there are no submodules configured */
+	if (!config_name_for_path.nr)
+		return;
+
+	init_revisions(&rev, NULL);
+	argv_array_push(&argv, "--"); /* argv[0] program name */
+	sha1_array_for_each_unique(&ref_tips_after_fetch,
+				   add_sha1_to_argv, &argv);
+	argv_array_push(&argv, "--not");
+	sha1_array_for_each_unique(&ref_tips_before_fetch,
+				   add_sha1_to_argv, &argv);
+	setup_revisions(argv.argc, argv.argv, &rev, NULL);
+	if (prepare_revision_walk(&rev))
+		die("revision walk setup failed");
+
+	/*
+	 * Collect all submodules (whether checked out or not) for which new
+	 * commits have been recorded upstream in "changed_submodule_paths".
+	 */
+	while ((commit = get_revision(&rev))) {
+		struct commit_list *parent = commit->parents;
+		while (parent) {
+			struct diff_options diff_opts;
+			diff_setup(&diff_opts);
+			DIFF_OPT_SET(&diff_opts, RECURSIVE);
+			diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
+			diff_opts.format_callback = submodule_collect_changed_cb;
+			diff_setup_done(&diff_opts);
+			diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
+			diffcore_std(&diff_opts);
+			diff_flush(&diff_opts);
+			parent = parent->next;
+		}
+	}
+
+	argv_array_clear(&argv);
+	sha1_array_clear(&ref_tips_before_fetch);
+	sha1_array_clear(&ref_tips_after_fetch);
+	initialized_fetch_ref_tips = 0;
+}
+
+int fetch_populated_submodules(const struct argv_array *options,
+			       const char *prefix, int command_line_option,
 			       int quiet)
 {
-	int i, result = 0, argc = 0;
+	int i, result = 0;
 	struct child_process cp;
-	const char **argv;
+	struct argv_array argv = ARGV_ARRAY_INIT;
 	struct string_list_item *name_for_path;
 	const char *work_tree = get_git_work_tree();
 	if (!work_tree)
-		return 0;
+		goto out;
 
 	if (!the_index.initialized)
 		if (read_cache() < 0)
 			die("index file corrupt");
 
-	/* 4: "fetch" (options) "--submodule-prefix" prefix NULL */
-	argv = xcalloc(num_options + 4, sizeof(const char *));
-	argv[argc++] = "fetch";
-	for (i = 0; i < num_options; i++)
-		argv[argc++] = options[i];
-	argv[argc++] = "--submodule-prefix";
+	argv_array_push(&argv, "fetch");
+	for (i = 0; i < options->argc; i++)
+		argv_array_push(&argv, options->argv[i]);
+	argv_array_push(&argv, "--recurse-submodules-default");
+	/* default value, "--submodule-prefix" and its value are added later */
 
 	memset(&cp, 0, sizeof(cp));
-	cp.argv = argv;
 	cp.env = local_repo_env;
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
 
+	calculate_changed_submodule_paths();
+
 	for (i = 0; i < active_nr; i++) {
 		struct strbuf submodule_path = STRBUF_INIT;
 		struct strbuf submodule_git_dir = STRBUF_INIT;
 		struct strbuf submodule_prefix = STRBUF_INIT;
 		struct cache_entry *ce = active_cache[i];
-		const char *git_dir, *name;
+		const char *git_dir, *name, *default_argv;
 
 		if (!S_ISGITLINK(ce->ce_mode))
 			continue;
@@ -311,37 +632,61 @@ int fetch_populated_submodules(int num_options, const char **options,
 		if (name_for_path)
 			name = name_for_path->util;
 
-		if (!ignore_config) {
+		default_argv = "yes";
+		if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
 			struct string_list_item *fetch_recurse_submodules_option;
 			fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
 			if (fetch_recurse_submodules_option) {
-				if (!fetch_recurse_submodules_option->util)
+				if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
 					continue;
+				if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
+					if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
+						continue;
+					default_argv = "on-demand";
+				}
 			} else {
-				if (!config_fetch_recurse_submodules)
+				if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
+				    gitmodules_is_unmerged)
 					continue;
+				if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
+					if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
+						continue;
+					default_argv = "on-demand";
+				}
 			}
+		} else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
+			if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
+				continue;
+			default_argv = "on-demand";
 		}
 
 		strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
 		strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
 		strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
-		git_dir = read_gitfile_gently(submodule_git_dir.buf);
+		git_dir = read_gitfile(submodule_git_dir.buf);
 		if (!git_dir)
 			git_dir = submodule_git_dir.buf;
 		if (is_directory(git_dir)) {
 			if (!quiet)
 				printf("Fetching submodule %s%s\n", prefix, ce->name);
 			cp.dir = submodule_path.buf;
-			argv[argc] = submodule_prefix.buf;
+			argv_array_push(&argv, default_argv);
+			argv_array_push(&argv, "--submodule-prefix");
+			argv_array_push(&argv, submodule_prefix.buf);
+			cp.argv = argv.argv;
 			if (run_command(&cp))
 				result = 1;
+			argv_array_pop(&argv);
+			argv_array_pop(&argv);
+			argv_array_pop(&argv);
 		}
 		strbuf_release(&submodule_path);
 		strbuf_release(&submodule_git_dir);
 		strbuf_release(&submodule_prefix);
 	}
-	free(argv);
+	argv_array_clear(&argv);
+out:
+	string_list_clear(&changed_submodule_paths, 1);
 	return result;
 }
 
@@ -361,7 +706,7 @@ unsigned is_submodule_modified(const char *path, int ignore_untracked)
 	const char *git_dir;
 
 	strbuf_addf(&buf, "%s/.git", path);
-	git_dir = read_gitfile_gently(buf.buf);
+	git_dir = read_gitfile(buf.buf);
 	if (!git_dir)
 		git_dir = buf.buf;
 	if (!is_directory(git_dir)) {
@@ -383,7 +728,7 @@ unsigned is_submodule_modified(const char *path, int ignore_untracked)
 	cp.out = -1;
 	cp.dir = path;
 	if (start_command(&cp))
-		die("Could not run git status --porcelain");
+		die("Could not run 'git status --porcelain' in submodule %s", path);
 
 	len = strbuf_read(&buf, cp.out, 1024);
 	line = buf.buf;
@@ -408,12 +753,92 @@ unsigned is_submodule_modified(const char *path, int ignore_untracked)
 	close(cp.out);
 
 	if (finish_command(&cp))
-		die("git status --porcelain failed");
+		die("'git status --porcelain' failed in submodule %s", path);
 
 	strbuf_release(&buf);
 	return dirty_submodule;
 }
 
+int submodule_uses_gitfile(const char *path)
+{
+	struct child_process cp;
+	const char *argv[] = {
+		"submodule",
+		"foreach",
+		"--quiet",
+		"--recursive",
+		"test -f .git",
+		NULL,
+	};
+	struct strbuf buf = STRBUF_INIT;
+	const char *git_dir;
+
+	strbuf_addf(&buf, "%s/.git", path);
+	git_dir = read_gitfile(buf.buf);
+	if (!git_dir) {
+		strbuf_release(&buf);
+		return 0;
+	}
+	strbuf_release(&buf);
+
+	/* Now test that all nested submodules use a gitfile too */
+	memset(&cp, 0, sizeof(cp));
+	cp.argv = argv;
+	cp.env = local_repo_env;
+	cp.git_cmd = 1;
+	cp.no_stdin = 1;
+	cp.no_stderr = 1;
+	cp.no_stdout = 1;
+	cp.dir = path;
+	if (run_command(&cp))
+		return 0;
+
+	return 1;
+}
+
+int ok_to_remove_submodule(const char *path)
+{
+	struct stat st;
+	ssize_t len;
+	struct child_process cp;
+	const char *argv[] = {
+		"status",
+		"--porcelain",
+		"-u",
+		"--ignore-submodules=none",
+		NULL,
+	};
+	struct strbuf buf = STRBUF_INIT;
+	int ok_to_remove = 1;
+
+	if ((lstat(path, &st) < 0) || is_empty_dir(path))
+		return 1;
+
+	if (!submodule_uses_gitfile(path))
+		return 0;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.argv = argv;
+	cp.env = local_repo_env;
+	cp.git_cmd = 1;
+	cp.no_stdin = 1;
+	cp.out = -1;
+	cp.dir = path;
+	if (start_command(&cp))
+		die("Could not run 'git status --porcelain -uall --ignore-submodules=none' in submodule %s", path);
+
+	len = strbuf_read(&buf, cp.out, 1024);
+	if (len > 2)
+		ok_to_remove = 0;
+	close(cp.out);
+
+	if (finish_command(&cp))
+		die("'git status --porcelain -uall --ignore-submodules=none' failed in submodule %s", path);
+
+	strbuf_release(&buf);
+	return ok_to_remove;
+}
+
 static int find_first_merges(struct object_array *result, const char *path,
 		struct commit *a, struct commit *b)
 {
@@ -444,9 +869,10 @@ static int find_first_merges(struct object_array *result, const char *path,
 		die("revision walk setup failed");
 	while ((commit = get_revision(&revs)) != NULL) {
 		struct object *o = &(commit->object);
-		if (in_merge_bases(b, &commit, 1))
+		if (in_merge_bases(b, commit))
 			add_object_array(o, NULL, &merges);
 	}
+	reset_revision_walk();
 
 	/* Now we've got all merges that contain a and b. Prune all
 	 * merges that contain another found merge and save them in
@@ -458,7 +884,7 @@ static int find_first_merges(struct object_array *result, const char *path,
 		contains_another = 0;
 		for (j = 0; j < merges.nr; j++) {
 			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j && in_merge_bases(m2, &m1, 1)) {
+			if (i != j && in_merge_bases(m2, m1)) {
 				contains_another = 1;
 				break;
 			}
@@ -488,7 +914,7 @@ static void print_commit(struct commit *commit)
 
 int merge_submodule(unsigned char result[20], const char *path,
 		    const unsigned char base[20], const unsigned char a[20],
-		    const unsigned char b[20])
+		    const unsigned char b[20], int search)
 {
 	struct commit *commit_base, *commit_a, *commit_b;
 	int parent_count;
@@ -520,18 +946,18 @@ int merge_submodule(unsigned char result[20], const char *path,
 	}
 
 	/* check whether both changes are forward */
-	if (!in_merge_bases(commit_base, &commit_a, 1) ||
-	    !in_merge_bases(commit_base, &commit_b, 1)) {
+	if (!in_merge_bases(commit_base, commit_a) ||
+	    !in_merge_bases(commit_base, commit_b)) {
 		MERGE_WARNING(path, "commits don't follow merge-base");
 		return 0;
 	}
 
 	/* Case #1: a is contained in b or vice versa */
-	if (in_merge_bases(commit_a, &commit_b, 1)) {
+	if (in_merge_bases(commit_a, commit_b)) {
 		hashcpy(result, b);
 		return 1;
 	}
-	if (in_merge_bases(commit_b, &commit_a, 1)) {
+	if (in_merge_bases(commit_b, commit_a)) {
 		hashcpy(result, a);
 		return 1;
 	}
@@ -543,6 +969,10 @@ int merge_submodule(unsigned char result[20], const char *path,
 	 * user needs to confirm the resolution.
 	 */
 
+	/* Skip the search if makes no sense to the calling context.  */
+	if (!search)
+		return 0;
+
 	/* find commit which merges them */
 	parent_count = find_first_merges(&merges, path, commit_a, commit_b);
 	switch (parent_count) {