1 files changed, 195 insertions, 138 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index 601f801158..ca259af441 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -3,6 +3,7 @@
  *
  * Copyright (c) 2006 Junio C Hamano
  */
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "repository.h"
 #include "config.h"
@@ -23,6 +24,7 @@
 #include "submodule.h"
 #include "submodule-config.h"
 #include "object-store.h"
+#include "packfile.h"
 
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
@@ -31,10 +33,8 @@ static char const * const grep_usage[] = {
 
 static int recurse_submodules;
 
-#define GREP_NUM_THREADS_DEFAULT 8
 static int num_threads;
 
-#ifndef NO_PTHREADS
 static pthread_t *threads;
 
 /* We use one producer thread and THREADS consumer
@@ -70,13 +70,11 @@ static pthread_mutex_t grep_mutex;
 
 static inline void grep_lock(void)
 {
-	assert(num_threads);
 	pthread_mutex_lock(&grep_mutex);
 }
 
 static inline void grep_unlock(void)
 {
-	assert(num_threads);
 	pthread_mutex_unlock(&grep_mutex);
 }
 
@@ -93,8 +91,11 @@ static pthread_cond_t cond_result;
 
 static int skip_first_line;
 
-static void add_work(struct grep_opt *opt, const struct grep_source *gs)
+static void add_work(struct grep_opt *opt, struct grep_source *gs)
 {
+	if (opt->binary != GREP_BINARY_TEXT)
+		grep_source_load_driver(gs, opt->repo->index);
+
 	grep_lock();
 
 	while ((todo_end+1) % ARRAY_SIZE(todo) == todo_done) {
@@ -102,8 +103,6 @@ static void add_work(struct grep_opt *opt, const struct grep_source *gs)
 	}
 
 	todo[todo_end].source = *gs;
-	if (opt->binary != GREP_BINARY_TEXT)
-		grep_source_load_driver(&todo[todo_end].source);
 	todo[todo_end].done = 0;
 	strbuf_reset(&todo[todo_end].out);
 	todo_end = (todo_end + 1) % ARRAY_SIZE(todo);
@@ -201,12 +200,12 @@ static void start_threads(struct grep_opt *opt)
 	int i;
 
 	pthread_mutex_init(&grep_mutex, NULL);
-	pthread_mutex_init(&grep_read_mutex, NULL);
 	pthread_mutex_init(&grep_attr_mutex, NULL);
 	pthread_cond_init(&cond_add, NULL);
 	pthread_cond_init(&cond_write, NULL);
 	pthread_cond_init(&cond_result, NULL);
 	grep_use_locks = 1;
+	enable_obj_read_lock();
 
 	for (i = 0; i < ARRAY_SIZE(todo); i++) {
 		strbuf_init(&todo[i].out, 0);
@@ -233,6 +232,9 @@ static int wait_all(void)
 	int hit = 0;
 	int i;
 
+	if (!HAVE_THREADS)
+		BUG("Never call this function unless you have started threads");
+
 	grep_lock();
 	all_work_added = 1;
 
@@ -255,22 +257,15 @@ static int wait_all(void)
 	free(threads);
 
 	pthread_mutex_destroy(&grep_mutex);
-	pthread_mutex_destroy(&grep_read_mutex);
 	pthread_mutex_destroy(&grep_attr_mutex);
 	pthread_cond_destroy(&cond_add);
 	pthread_cond_destroy(&cond_write);
 	pthread_cond_destroy(&cond_result);
 	grep_use_locks = 0;
+	disable_obj_read_lock();
 
 	return hit;
 }
-#else /* !NO_PTHREADS */
-
-static int wait_all(void)
-{
-	return 0;
-}
-#endif
 
 static int grep_cmd_config(const char *var, const char *value, void *cb)
 {
@@ -283,17 +278,15 @@ static int grep_cmd_config(const char *var, const char *value, void *cb)
 		if (num_threads < 0)
 			die(_("invalid number of threads specified (%d) for %s"),
 			    num_threads, var);
-#ifdef NO_PTHREADS
-		else if (num_threads && num_threads != 1) {
+		else if (!HAVE_THREADS && num_threads > 1) {
 			/*
 			 * TRANSLATORS: %s is the configuration
 			 * variable for tweaking threads, currently
 			 * grep.threads
 			 */
 			warning(_("no threads support, ignoring %s"), var);
-			num_threads = 0;
+			num_threads = 1;
 		}
-#endif
 	}
 
 	if (!strcmp(var, "submodule.recurse"))
@@ -302,14 +295,36 @@ static int grep_cmd_config(const char *var, const char *value, void *cb)
 	return st;
 }
 
-static void *lock_and_read_oid_file(const struct object_id *oid, enum object_type *type, unsigned long *size)
+static void grep_source_name(struct grep_opt *opt, const char *filename,
+			     int tree_name_len, struct strbuf *out)
 {
-	void *data;
+	strbuf_reset(out);
 
-	grep_read_lock();
-	data = read_object_file(oid, type, size);
-	grep_read_unlock();
-	return data;
+	if (opt->null_following_name) {
+		if (opt->relative && opt->prefix_length) {
+			struct strbuf rel_buf = STRBUF_INIT;
+			const char *rel_name =
+				relative_path(filename + tree_name_len,
+					      opt->prefix, &rel_buf);
+
+			if (tree_name_len)
+				strbuf_add(out, filename, tree_name_len);
+
+			strbuf_addstr(out, rel_name);
+			strbuf_release(&rel_buf);
+		} else {
+			strbuf_addstr(out, filename);
+		}
+		return;
+	}
+
+	if (opt->relative && opt->prefix_length)
+		quote_path(filename + tree_name_len, opt->prefix, out, 0);
+	else
+		quote_c_style(filename + tree_name_len, out, NULL, 0);
+
+	if (tree_name_len)
+		strbuf_insert(out, 0, filename, tree_name_len);
 }
 
 static int grep_oid(struct grep_opt *opt, const struct object_id *oid,
@@ -319,27 +334,18 @@ static int grep_oid(struct grep_opt *opt, const struct object_id *oid,
 	struct strbuf pathbuf = STRBUF_INIT;
 	struct grep_source gs;
 
-	if (opt->relative && opt->prefix_length) {
-		quote_path_relative(filename + tree_name_len, opt->prefix, &pathbuf);
-		strbuf_insert(&pathbuf, 0, filename, tree_name_len);
-	} else {
-		strbuf_addstr(&pathbuf, filename);
-	}
-
+	grep_source_name(opt, filename, tree_name_len, &pathbuf);
 	grep_source_init(&gs, GREP_SOURCE_OID, pathbuf.buf, path, oid);
 	strbuf_release(&pathbuf);
 
-#ifndef NO_PTHREADS
-	if (num_threads) {
+	if (num_threads > 1) {
 		/*
 		 * add_work() copies gs and thus assumes ownership of
 		 * its fields, so do not call grep_source_clear()
 		 */
 		add_work(opt, &gs);
 		return 0;
-	} else
-#endif
-	{
+	} else {
 		int hit;
 
 		hit = grep_source(opt, &gs);
@@ -354,25 +360,18 @@ static int grep_file(struct grep_opt *opt, const char *filename)
 	struct strbuf buf = STRBUF_INIT;
 	struct grep_source gs;
 
-	if (opt->relative && opt->prefix_length)
-		quote_path_relative(filename, opt->prefix, &buf);
-	else
-		strbuf_addstr(&buf, filename);
-
+	grep_source_name(opt, filename, 0, &buf);
 	grep_source_init(&gs, GREP_SOURCE_FILE, buf.buf, filename, filename);
 	strbuf_release(&buf);
 
-#ifndef NO_PTHREADS
-	if (num_threads) {
+	if (num_threads > 1) {
 		/*
 		 * add_work() copies gs and thus assumes ownership of
 		 * its fields, so do not call grep_source_clear()
 		 */
 		add_work(opt, &gs);
 		return 0;
-	} else
-#endif
-	{
+	} else {
 		int hit;
 
 		hit = grep_source(opt, &gs);
@@ -398,7 +397,7 @@ static void run_pager(struct grep_opt *opt, const char *prefix)
 	int i, status;
 
 	for (i = 0; i < path_list->nr; i++)
-		argv_array_push(&child.args, path_list->items[i].string);
+		strvec_push(&child.args, path_list->items[i].string);
 	child.dir = prefix;
 	child.use_shell = 1;
 
@@ -407,27 +406,41 @@ static void run_pager(struct grep_opt *opt, const char *prefix)
 		exit(status);
 }
 
-static int grep_cache(struct grep_opt *opt, struct repository *repo,
+static int grep_cache(struct grep_opt *opt,
 		      const struct pathspec *pathspec, int cached);
 static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		     struct tree_desc *tree, struct strbuf *base, int tn_len,
-		     int check_attr, struct repository *repo);
+		     int check_attr);
 
-static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
+static int grep_submodule(struct grep_opt *opt,
 			  const struct pathspec *pathspec,
 			  const struct object_id *oid,
-			  const char *filename, const char *path)
+			  const char *filename, const char *path, int cached)
 {
-	struct repository submodule;
+	struct repository subrepo;
+	struct repository *superproject = opt->repo;
+	const struct submodule *sub;
+	struct grep_opt subopt;
 	int hit;
 
+	sub = submodule_from_path(superproject, &null_oid, path);
+
 	if (!is_submodule_active(superproject, path))
 		return 0;
 
-	if (repo_submodule_init(&submodule, superproject, path))
+	if (repo_submodule_init(&subrepo, superproject, sub))
 		return 0;
 
-	repo_read_gitmodules(&submodule);
+	/*
+	 * NEEDSWORK: repo_read_gitmodules() might call
+	 * add_to_alternates_memory() via config_from_gitmodules(). This
+	 * operation causes a race condition with concurrent object readings
+	 * performed by the worker threads. That's why we need obj_read_lock()
+	 * here. It should be removed once it's no longer necessary to add the
+	 * subrepo's odbs to the in-memory alternates list.
+	 */
+	obj_read_lock();
+	repo_read_gitmodules(&subrepo, 0);
 
 	/*
 	 * NEEDSWORK: This adds the submodule's object directory to the list of
@@ -439,9 +452,11 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 	 * store is no longer global and instead is a member of the repository
 	 * object.
 	 */
-	grep_read_lock();
-	add_to_alternates_memory(submodule.objects->objectdir);
-	grep_read_unlock();
+	add_to_alternates_memory(subrepo.objects->odb->path);
+	obj_read_unlock();
+
+	memcpy(&subopt, opt, sizeof(subopt));
+	subopt.repo = &subrepo;
 
 	if (oid) {
 		struct object *object;
@@ -450,13 +465,12 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 		unsigned long size;
 		struct strbuf base = STRBUF_INIT;
 
-		object = parse_object_or_die(oid, oid_to_hex(oid));
-
-		grep_read_lock();
-		data = read_object_with_reference(&object->oid, tree_type,
+		obj_read_lock();
+		object = parse_object_or_die(oid, NULL);
+		obj_read_unlock();
+		data = read_object_with_reference(&subrepo,
+						  &object->oid, tree_type,
 						  &size, NULL);
-		grep_read_unlock();
-
 		if (!data)
 			die(_("unable to read tree (%s)"), oid_to_hex(&object->oid));
 
@@ -464,21 +478,22 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 		strbuf_addch(&base, '/');
 
 		init_tree_desc(&tree, data, size);
-		hit = grep_tree(opt, pathspec, &tree, &base, base.len,
-				object->type == OBJ_COMMIT, &submodule);
+		hit = grep_tree(&subopt, pathspec, &tree, &base, base.len,
+				object->type == OBJ_COMMIT);
 		strbuf_release(&base);
 		free(data);
 	} else {
-		hit = grep_cache(opt, &submodule, pathspec, 1);
+		hit = grep_cache(&subopt, pathspec, cached);
 	}
 
-	repo_clear(&submodule);
+	repo_clear(&subrepo);
 	return hit;
 }
 
-static int grep_cache(struct grep_opt *opt, struct repository *repo,
+static int grep_cache(struct grep_opt *opt,
 		      const struct pathspec *pathspec, int cached)
 {
+	struct repository *repo = opt->repo;
 	int hit = 0;
 	int nr;
 	struct strbuf name = STRBUF_INIT;
@@ -516,7 +531,8 @@ static int grep_cache(struct grep_opt *opt, struct repository *repo,
 			}
 		} else if (recurse_submodules && S_ISGITLINK(ce->ce_mode) &&
 			   submodule_path_match(repo->index, pathspec, name.buf, NULL)) {
-			hit |= grep_submodule(opt, repo, pathspec, NULL, ce->name, ce->name);
+			hit |= grep_submodule(opt, pathspec, NULL, ce->name,
+					      ce->name, cached);
 		} else {
 			continue;
 		}
@@ -538,8 +554,9 @@ static int grep_cache(struct grep_opt *opt, struct repository *repo,
 
 static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		     struct tree_desc *tree, struct strbuf *base, int tn_len,
-		     int check_attr, struct repository *repo)
+		     int check_attr)
 {
+	struct repository *repo = opt->repo;
 	int hit = 0;
 	enum interesting match = entry_not_interesting;
 	struct name_entry entry;
@@ -556,7 +573,8 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 
 		if (match != all_entries_interesting) {
 			strbuf_addstr(&name, base->buf + tn_len);
-			match = tree_entry_interesting(&entry, &name,
+			match = tree_entry_interesting(repo->index,
+						       &entry, &name,
 						       0, pathspec);
 			strbuf_setlen(&name, name_base_len);
 
@@ -569,7 +587,7 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		strbuf_add(base, entry.path, te_len);
 
 		if (S_ISREG(entry.mode)) {
-			hit |= grep_oid(opt, entry.oid, base->buf, tn_len,
+			hit |= grep_oid(opt, &entry.oid, base->buf, tn_len,
 					 check_attr ? base->buf + tn_len : NULL);
 		} else if (S_ISDIR(entry.mode)) {
 			enum object_type type;
@@ -577,19 +595,20 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 			void *data;
 			unsigned long size;
 
-			data = lock_and_read_oid_file(entry.oid, &type, &size);
+			data = read_object_file(&entry.oid, &type, &size);
 			if (!data)
 				die(_("unable to read tree (%s)"),
-				    oid_to_hex(entry.oid));
+				    oid_to_hex(&entry.oid));
 
 			strbuf_addch(base, '/');
 			init_tree_desc(&sub, data, size);
 			hit |= grep_tree(opt, pathspec, &sub, base, tn_len,
-					 check_attr, repo);
+					 check_attr);
 			free(data);
 		} else if (recurse_submodules && S_ISGITLINK(entry.mode)) {
-			hit |= grep_submodule(opt, repo, pathspec, entry.oid,
-					      base->buf, base->buf + tn_len);
+			hit |= grep_submodule(opt, pathspec, &entry.oid,
+					      base->buf, base->buf + tn_len,
+					      1); /* ignored */
 		}
 
 		strbuf_setlen(base, old_baselen);
@@ -614,11 +633,9 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 		struct strbuf base;
 		int hit, len;
 
-		grep_read_lock();
-		data = read_object_with_reference(&obj->oid, tree_type,
+		data = read_object_with_reference(opt->repo,
+						  &obj->oid, tree_type,
 						  &size, NULL);
-		grep_read_unlock();
-
 		if (!data)
 			die(_("unable to read tree (%s)"), oid_to_hex(&obj->oid));
 
@@ -630,7 +647,7 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 		}
 		init_tree_desc(&tree, data, size);
 		hit = grep_tree(opt, pathspec, &tree, &base, base.len,
-				obj->type == OBJ_COMMIT, the_repository);
+				obj->type == OBJ_COMMIT);
 		strbuf_release(&base);
 		free(data);
 		return hit;
@@ -647,13 +664,29 @@ static int grep_objects(struct grep_opt *opt, const struct pathspec *pathspec,
 
 	for (i = 0; i < nr; i++) {
 		struct object *real_obj;
-		real_obj = deref_tag(the_repository, list->objects[i].item,
+
+		obj_read_lock();
+		real_obj = deref_tag(opt->repo, list->objects[i].item,
 				     NULL, 0);
+		obj_read_unlock();
+
+		if (!real_obj) {
+			char hex[GIT_MAX_HEXSZ + 1];
+			const char *name = list->objects[i].name;
+
+			if (!name) {
+				oid_to_hex_r(hex, &list->objects[i].item->oid);
+				name = hex;
+			}
+			die(_("invalid object '%s' given."), name);
+		}
 
 		/* load the gitmodules file for this rev */
 		if (recurse_submodules) {
-			submodule_free(the_repository);
+			submodule_free(opt->repo);
+			obj_read_lock();
 			gitmodules_config_oid(&real_obj->oid);
+			obj_read_unlock();
 		}
 		if (grep_object(opt, pathspec, real_obj, list->objects[i].name,
 				list->objects[i].path)) {
@@ -671,20 +704,19 @@ static int grep_directory(struct grep_opt *opt, const struct pathspec *pathspec,
 	struct dir_struct dir;
 	int i, hit = 0;
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	if (!use_index)
 		dir.flags |= DIR_NO_GITLINKS;
 	if (exc_std)
 		setup_standard_excludes(&dir);
 
-	fill_directory(&dir, &the_index, pathspec);
+	fill_directory(&dir, opt->repo->index, pathspec);
 	for (i = 0; i < dir.nr; i++) {
-		if (!dir_path_match(&the_index, dir.entries[i], pathspec, 0, NULL))
-			continue;
 		hit |= grep_file(opt, dir.entries[i]->name);
 		if (hit && opt->status_only)
 			break;
 	}
+	dir_clear(&dir);
 	return hit;
 }
 
@@ -711,11 +743,14 @@ static int context_callback(const struct option *opt, const char *arg,
 static int file_callback(const struct option *opt, const char *arg, int unset)
 {
 	struct grep_opt *grep_opt = opt->value;
-	int from_stdin = !strcmp(arg, "-");
+	int from_stdin;
 	FILE *patterns;
 	int lno = 0;
 	struct strbuf sb = STRBUF_INIT;
 
+	BUG_ON_OPT_NEG(unset);
+
+	from_stdin = !strcmp(arg, "-");
 	patterns = from_stdin ? stdin : fopen(arg, "r");
 	if (!patterns)
 		die_errno(_("cannot open '%s'"), arg);
@@ -736,6 +771,8 @@ static int file_callback(const struct option *opt, const char *arg, int unset)
 static int not_callback(const struct option *opt, const char *arg, int unset)
 {
 	struct grep_opt *grep_opt = opt->value;
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
 	append_grep_pattern(grep_opt, "--not", "command line", 0, GREP_NOT);
 	return 0;
 }
@@ -743,6 +780,8 @@ static int not_callback(const struct option *opt, const char *arg, int unset)
 static int and_callback(const struct option *opt, const char *arg, int unset)
 {
 	struct grep_opt *grep_opt = opt->value;
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
 	append_grep_pattern(grep_opt, "--and", "command line", 0, GREP_AND);
 	return 0;
 }
@@ -750,6 +789,8 @@ static int and_callback(const struct option *opt, const char *arg, int unset)
 static int open_callback(const struct option *opt, const char *arg, int unset)
 {
 	struct grep_opt *grep_opt = opt->value;
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
 	append_grep_pattern(grep_opt, "(", "command line", 0, GREP_OPEN_PAREN);
 	return 0;
 }
@@ -757,6 +798,8 @@ static int open_callback(const struct option *opt, const char *arg, int unset)
 static int close_callback(const struct option *opt, const char *arg, int unset)
 {
 	struct grep_opt *grep_opt = opt->value;
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
 	append_grep_pattern(grep_opt, ")", "command line", 0, GREP_CLOSE_PAREN);
 	return 0;
 }
@@ -765,6 +808,7 @@ static int pattern_callback(const struct option *opt, const char *arg,
 			    int unset)
 {
 	struct grep_opt *grep_opt = opt->value;
+	BUG_ON_OPT_NEG(unset);
 	append_grep_pattern(grep_opt, arg, "-e option", 0, GREP_PATTERN);
 	return 0;
 }
@@ -811,6 +855,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			GREP_BINARY_NOMATCH),
 		OPT_BOOL(0, "textconv", &opt.allow_textconv,
 			 N_("process binary files with textconv filters")),
+		OPT_SET_INT('r', "recursive", &opt.max_depth,
+			    N_("search in subdirectories (default)"), -1),
 		{ OPTION_INTEGER, 0, "max-depth", &opt.max_depth, N_("depth"),
 			N_("descend at most <depth> levels"), PARSE_OPT_NONEG,
 			NULL, 1 },
@@ -872,20 +918,20 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		OPT_GROUP(""),
 		OPT_CALLBACK('f', NULL, &opt, N_("file"),
 			N_("read patterns from file"), file_callback),
-		{ OPTION_CALLBACK, 'e', NULL, &opt, N_("pattern"),
-			N_("match <pattern>"), PARSE_OPT_NONEG, pattern_callback },
-		{ OPTION_CALLBACK, 0, "and", &opt, NULL,
-		  N_("combine patterns specified with -e"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, and_callback },
+		OPT_CALLBACK_F('e', NULL, &opt, N_("pattern"),
+			N_("match <pattern>"), PARSE_OPT_NONEG, pattern_callback),
+		OPT_CALLBACK_F(0, "and", &opt, NULL,
+			N_("combine patterns specified with -e"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, and_callback),
 		OPT_BOOL(0, "or", &dummy, ""),
-		{ OPTION_CALLBACK, 0, "not", &opt, NULL, "",
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, not_callback },
-		{ OPTION_CALLBACK, '(', NULL, &opt, NULL, "",
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
-		  open_callback },
-		{ OPTION_CALLBACK, ')', NULL, &opt, NULL, "",
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
-		  close_callback },
+		OPT_CALLBACK_F(0, "not", &opt, NULL, "",
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, not_callback),
+		OPT_CALLBACK_F('(', NULL, &opt, NULL, "",
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
+			open_callback),
+		OPT_CALLBACK_F(')', NULL, &opt, NULL, "",
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
+			close_callback),
 		OPT__QUIET(&opt.status_only,
 			   N_("indicate hit with exit status without output")),
 		OPT_BOOL(0, "all-match", &opt.all_match,
@@ -904,9 +950,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	init_grep_defaults();
 	git_config(grep_cmd_config, NULL);
-	grep_init(&opt, prefix);
+	grep_init(&opt, the_repository, prefix);
 
 	/*
 	 * If there is no -- then the paths must exist in the working
@@ -932,6 +977,9 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			/* die the same way as if we did it at the beginning */
 			setup_git_directory();
 	}
+	/* Ignore --recurse-submodules if --no-index is given or implied */
+	if (!use_index)
+		recurse_submodules = 0;
 
 	/*
 	 * skip a -- separator; we know it cannot be
@@ -1003,7 +1051,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			break;
 		}
 
-		if (get_oid_with_context(arg, GET_OID_RECORD_PATH,
+		if (get_oid_with_context(the_repository, arg,
+					 GET_OID_RECORD_PATH,
 					 &oid, &oc)) {
 			if (seen_dashdash)
 				die(_("unable to resolve revision: %s"), arg);
@@ -1035,39 +1084,49 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	pathspec.recursive = 1;
 	pathspec.recurse_submodules = !!recurse_submodules;
 
-#ifndef NO_PTHREADS
-	if (list.nr || cached || show_in_pager)
-		num_threads = 0;
-	else if (num_threads == 0)
-		num_threads = GREP_NUM_THREADS_DEFAULT;
-	else if (num_threads < 0)
-		die(_("invalid number of threads specified (%d)"), num_threads);
-	if (num_threads == 1)
-		num_threads = 0;
-#else
-	if (num_threads)
+	if (recurse_submodules && untracked)
+		die(_("--untracked not supported with --recurse-submodules"));
+
+	if (show_in_pager) {
+		if (num_threads > 1)
+			warning(_("invalid option combination, ignoring --threads"));
+		num_threads = 1;
+	} else if (!HAVE_THREADS && num_threads > 1) {
 		warning(_("no threads support, ignoring --threads"));
-	num_threads = 0;
-#endif
+		num_threads = 1;
+	} else if (num_threads < 0)
+		die(_("invalid number of threads specified (%d)"), num_threads);
+	else if (num_threads == 0)
+		num_threads = HAVE_THREADS ? online_cpus() : 1;
 
-	if (!num_threads)
+	if (num_threads > 1) {
+		if (!HAVE_THREADS)
+			BUG("Somebody got num_threads calculation wrong!");
+		if (!(opt.name_only || opt.unmatch_name_only || opt.count)
+		    && (opt.pre_context || opt.post_context ||
+			opt.file_break || opt.funcbody))
+			skip_first_line = 1;
+
+		/*
+		 * Pre-read gitmodules (if not read already) and force eager
+		 * initialization of packed_git to prevent racy lazy
+		 * reading/initialization once worker threads are started.
+		 */
+		if (recurse_submodules)
+			repo_read_gitmodules(the_repository, 1);
+		if (startup_info->have_repository)
+			(void)get_packed_git(the_repository);
+
+		start_threads(&opt);
+	} else {
 		/*
 		 * The compiled patterns on the main path are only
 		 * used when not using threading. Otherwise
-		 * start_threads() below calls compile_grep_patterns()
+		 * start_threads() above calls compile_grep_patterns()
 		 * for each thread.
 		 */
 		compile_grep_patterns(&opt);
-
-#ifndef NO_PTHREADS
-	if (num_threads) {
-		if (!(opt.name_only || opt.unmatch_name_only || opt.count)
-		    && (opt.pre_context || opt.post_context ||
-			opt.file_break || opt.funcbody))
-			skip_first_line = 1;
-		start_threads(&opt);
 	}
-#endif
 
 	if (show_in_pager && (cached || list.nr))
 		die(_("--open-files-in-pager only works on the worktree"));
@@ -1087,14 +1146,11 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			strbuf_addf(&buf, "+/%s%s",
 					strcmp("less", pager) ? "" : "*",
 					opt.pattern_list->pattern);
-			string_list_append(&path_list, buf.buf);
-			strbuf_detach(&buf, NULL);
+			string_list_append(&path_list,
+					   strbuf_detach(&buf, NULL));
 		}
 	}
 
-	if (recurse_submodules && (!use_index || untracked))
-		die(_("option not supported with --recurse-submodules"));
-
 	if (!show_in_pager && !opt.status_only)
 		setup_pager();
 
@@ -1110,7 +1166,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		if (!cached)
 			setup_work_tree();
 
-		hit = grep_cache(&opt, the_repository, &pathspec, cached);
+		hit = grep_cache(&opt, &pathspec, cached);
 	} else {
 		if (cached)
 			die(_("both --cached and trees are given"));
@@ -1118,11 +1174,12 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		hit = grep_objects(&opt, &pathspec, &list);
 	}
 
-	if (num_threads)
+	if (num_threads > 1)
 		hit |= wait_all();
 	if (hit && show_in_pager)
 		run_pager(&opt, prefix);
 	clear_pathspec(&pathspec);
 	free_grep_patterns(&opt);
+	grep_destroy();
 	return !hit;
 }