Fix various sparse warnings in the git source code

There are a few remaining ones, but this fixes the trivial ones. It boils
down to two main issues that sparse complains about:

 - warning: Using plain integer as NULL pointer

   Sparse doesn't like you using '0' instead of 'NULL'. For various good
   reasons, not the least of which is just the visual confusion. A NULL
   pointer is not an integer, and that whole "0 works as NULL" is a
   historical accident and not very pretty.

   A few of these remain: zlib is a total mess, and Z_NULL is just a 0.
   I didn't touch those.

 - warning: symbol 'xyz' was not declared. Should it be static?

   Sparse wants to see declarations for any functions you export. A lack
   of a declaration tends to mean that you should either add one, or you
   should mark the function 'static' to show that it's in file scope.

   A few of these remain: I only did the ones that should obviously just
   be made static.

That 'wt_status_submodule_summary' one is debatable. It has a few related
flags (like 'wt_status_use_color') which _are_ declared, and are used by
builtin-commit.c. So maybe we'd like to export it at some point, but it's
not declared now, and not used outside of that file, so 'static' it is in
this patch.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bisect.c

@@ -454,7 +454,7 @@ static int read_bisect_refs(void)
 	return for_each_ref_in("refs/bisect/", register_ref, NULL);
 }
 
-void read_bisect_paths(struct argv_array *array)
+static void read_bisect_paths(struct argv_array *array)
 {
 	struct strbuf str = STRBUF_INIT;
 	const char *filename = git_path("BISECT_NAMES");
@@ -780,7 +780,7 @@ static void handle_bad_merge_base(void)
 	exit(1);
 }
 
-void handle_skipped_merge_base(const unsigned char *mb)
+static void handle_skipped_merge_base(const unsigned char *mb)
 {
 	char *mb_hex = sha1_to_hex(mb);
 	char *bad_hex = sha1_to_hex(current_bad_sha1);

builtin-add.c

@@ -189,7 +189,7 @@ int interactive_add(int argc, const char **argv, const char *prefix)
 	return status;
 }
 
-int edit_patch(int argc, const char **argv, const char *prefix)
+static int edit_patch(int argc, const char **argv, const char *prefix)
 {
 	char *file = xstrdup(git_path("ADD_EDIT.patch"));
 	const char *apply_argv[] = { "apply", "--recount", "--cached",

builtin-apply.c

@@ -2614,7 +2614,7 @@ static int get_current_sha1(const char *path, unsigned char *sha1)
 static void build_fake_ancestor(struct patch *list, const char *filename)
 {
 	struct patch *patch;
-	struct index_state result = { 0 };
+	struct index_state result = { NULL };
 	int fd;
 
 	/* Once we start supporting the reverse patch, it may be

builtin-clone.c

@@ -141,7 +141,7 @@ static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
 	if (is_bare) {
 		struct strbuf result = STRBUF_INIT;
 		strbuf_addf(&result, "%.*s.git", (int)(end - start), start);
-		dir = strbuf_detach(&result, 0);
+		dir = strbuf_detach(&result, NULL);
 	} else
 		dir = xstrndup(start, end - start);
 	/*

builtin-fsck.c

@@ -104,7 +104,7 @@ static int mark_object(struct object *obj, int type, void *data)
 
 static void mark_object_reachable(struct object *obj)
 {
-	mark_object(obj, OBJ_ANY, 0);
+	mark_object(obj, OBJ_ANY, NULL);
 }
 
 static int traverse_one_object(struct object *obj, struct object *parent)
@@ -292,7 +292,7 @@ static int fsck_sha1(const unsigned char *sha1)
 		fprintf(stderr, "Checking %s %s\n",
 			typename(obj->type), sha1_to_hex(obj->sha1));
 
-	if (fsck_walk(obj, mark_used, 0))
+	if (fsck_walk(obj, mark_used, NULL))
 		objerror(obj, "broken links");
 	if (fsck_object(obj, check_strict, fsck_error_func))
 		return -1;

builtin-help.c

@@ -394,7 +394,7 @@ static void get_html_page_path(struct strbuf *page_path, const char *page)
  * HTML.
  */
 #ifndef open_html
-void open_html(const char *path)
+static void open_html(const char *path)
 {
 	execl_git_cmd("web--browse", "-c", "help.browser", path, NULL);
 }

builtin-log.c

@@ -94,7 +94,7 @@ static void show_early_header(struct rev_info *rev, const char *stage, int nr)
 	printf("Final output: %d %s\n", nr, stage);
 }
 
-struct itimerval early_output_timer;
+static struct itimerval early_output_timer;
 
 static void log_show_early(struct rev_info *revs, struct commit_list *list)
 {
@@ -977,7 +977,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		strbuf_addch(&buf, '\n');
 	}
 
-	rev.extra_headers = strbuf_detach(&buf, 0);
+	rev.extra_headers = strbuf_detach(&buf, NULL);
 
 	if (start_number < 0)
 		start_number = 1;

builtin-merge.c

@@ -370,7 +370,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
 
 	strbuf_addstr(&buf, "refs/heads/");
 	strbuf_addstr(&buf, remote);
-	resolve_ref(buf.buf, branch_head, 0, 0);
+	resolve_ref(buf.buf, branch_head, 0, NULL);
 
 	if (!hashcmp(remote_head->sha1, branch_head)) {
 		strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
@@ -409,7 +409,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
 		strbuf_addstr(&truname, "refs/heads/");
 		strbuf_addstr(&truname, remote);
 		strbuf_setlen(&truname, truname.len - len);
-		if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
+		if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
 			strbuf_addf(msg,
 				    "%s\t\tbranch '%s'%s of .\n",
 				    sha1_to_hex(remote_head->sha1),

builtin-remote.c

@@ -740,7 +740,7 @@ static int rm(int argc, const char **argv)
 	return result;
 }
 
-void clear_push_info(void *util, const char *string)
+static void clear_push_info(void *util, const char *string)
 {
 	struct push_info *info = util;
 	free(info->dest);
@@ -815,7 +815,7 @@ struct show_info {
 	int any_rebase;
 };
 
-int add_remote_to_show_info(struct string_list_item *item, void *cb_data)
+static int add_remote_to_show_info(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *info = cb_data;
 	int n = strlen(item->string);
@@ -825,7 +825,7 @@ int add_remote_to_show_info(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
-int show_remote_info_item(struct string_list_item *item, void *cb_data)
+static int show_remote_info_item(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *info = cb_data;
 	struct ref_states *states = info->states;
@@ -852,7 +852,7 @@ int show_remote_info_item(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
-int add_local_to_show_info(struct string_list_item *branch_item, void *cb_data)
+static int add_local_to_show_info(struct string_list_item *branch_item, void *cb_data)
 {
 	struct show_info *show_info = cb_data;
 	struct ref_states *states = show_info->states;
@@ -874,7 +874,7 @@ int add_local_to_show_info(struct string_list_item *branch_item, void *cb_data)
 	return 0;
 }
 
-int show_local_info_item(struct string_list_item *item, void *cb_data)
+static int show_local_info_item(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *show_info = cb_data;
 	struct branch_info *branch_info = item->util;
@@ -906,7 +906,7 @@ int show_local_info_item(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
-int add_push_to_show_info(struct string_list_item *push_item, void *cb_data)
+static int add_push_to_show_info(struct string_list_item *push_item, void *cb_data)
 {
 	struct show_info *show_info = cb_data;
 	struct push_info *push_info = push_item->util;
@@ -935,7 +935,7 @@ static int cmp_string_with_push(const void *va, const void *vb)
 	return cmp ? cmp : strcmp(a_push->dest, b_push->dest);
 }
 
-int show_push_info_item(struct string_list_item *item, void *cb_data)
+static int show_push_info_item(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *show_info = cb_data;
 	struct push_info *push_info = item->util;
@@ -1197,7 +1197,7 @@ static int get_one_remote_for_update(struct remote *remote, void *priv)
 	return 0;
 }
 
-struct remote_group {
+static struct remote_group {
 	const char *name;
 	struct string_list *list;
 } remote_group;

builtin-unpack-objects.c

@@ -158,7 +158,7 @@ struct obj_info {
 #define FLAG_WRITTEN (1u<<21)
 
 static struct obj_info *obj_list;
-unsigned nr_objects;
+static unsigned nr_objects;
 
 /*
  * Called only from check_object() after it verified this object
@@ -200,7 +200,7 @@ static int check_object(struct object *obj, int type, void *data)
 
 	if (fsck_object(obj, 1, fsck_error_function))
 		die("Error in object");
-	if (!fsck_walk(obj, check_object, 0))
+	if (!fsck_walk(obj, check_object, NULL))
 		die("Error on reachable objects of %s", sha1_to_hex(obj->sha1));
 	write_cached_object(obj);
 	return 1;
@@ -210,7 +210,7 @@ static void write_rest(void)
 {
 	unsigned i;
 	for (i = 0; i < nr_objects; i++)
-		check_object(obj_list[i].obj, OBJ_ANY, 0);
+		check_object(obj_list[i].obj, OBJ_ANY, NULL);
 }
 
 static void added_object(unsigned nr, enum object_type type,

connect.c

@@ -464,7 +464,7 @@ static void git_proxy_connect(int fd[2], char *host)
 
 #define MAX_CMD_LEN 1024
 
-char *get_port(char *host)
+static char *get_port(char *host)
 {
 	char *end;
 	char *p = strchr(host, ':');

daemon.c

@@ -453,7 +453,7 @@ static void parse_host_arg(char *extra_args, int buflen)
 		memset(&hints, 0, sizeof(hints));
 		hints.ai_flags = AI_CANONNAME;
 
-		gai = getaddrinfo(hostname, 0, &hints, &ai);
+		gai = getaddrinfo(hostname, NULL, &hints, &ai);
 		if (!gai) {
 			struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 

http-push.c

@@ -1750,7 +1750,7 @@ static int delete_remote_branch(char *pattern, int force)
 	return 0;
 }
 
-void run_request_queue(void)
+static void run_request_queue(void)
 {
 #ifdef USE_CURL_MULTI
 	is_running_queue = 1;

imap-send.c

@@ -238,7 +238,7 @@ static const char *Flags[] = {
 #ifndef NO_OPENSSL
 static void ssl_socket_perror(const char *func)
 {
-	fprintf(stderr, "%s: %s\n", func, ERR_error_string(ERR_get_error(), 0));
+	fprintf(stderr, "%s: %s\n", func, ERR_error_string(ERR_get_error(), NULL));
 }
 #endif
 

index-pack.c

@@ -469,7 +469,7 @@ static void sha1_object(const void *data, unsigned long size,
 				die("invalid %s", typename(type));
 			if (fsck_object(obj, 1, fsck_error_function))
 				die("Error in object");
-			if (fsck_walk(obj, mark_link, 0))
+			if (fsck_walk(obj, mark_link, NULL))
 				die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 
 			if (obj->type == OBJ_TREE) {

mailmap.c

@@ -103,7 +103,7 @@ static char *parse_name_and_email(char *buffer, char **name,
 		char **email, int allow_empty_email)
 {
 	char *left, *right, *nstart, *nend;
-	*name = *email = 0;
+	*name = *email = NULL;
 
 	if ((left = strchr(buffer, '<')) == NULL)
 		return NULL;
@@ -136,7 +136,7 @@ static int read_single_mailmap(struct string_list *map, const char *filename, ch
 	if (f == NULL)
 		return 1;
 	while (fgets(buffer, sizeof(buffer), f) != NULL) {
-		char *name1 = 0, *email1 = 0, *name2 = 0, *email2 = 0;
+		char *name1 = NULL, *email1 = NULL, *name2 = NULL, *email2 = NULL;
 		if (buffer[0] == '#') {
 			static const char abbrev[] = "# repo-abbrev:";
 			int abblen = sizeof(abbrev) - 1;
@@ -200,7 +200,7 @@ int map_user(struct string_list *map,
 	if (!p) {
 		/* email passed in might not be wrapped in <>, but end with a \0 */
 		p = memchr(email, '\0', maxlen_email);
-		if (p == 0)
+		if (!p)
 			return 0;
 	}
 	if (p - email + 1 < sizeof(buf))

merge-recursive.c

@@ -38,7 +38,7 @@ static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  * A virtual commit has (const char *)commit->util set to the name.
  */
 
-struct commit *make_virtual_commit(struct tree *tree, const char *comment)
+static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 {
 	struct commit *commit = xcalloc(1, sizeof(struct commit));
 	commit->tree = tree;

parse-options.c

@@ -478,7 +478,7 @@ static int usage_argh(const struct option *opts)
 #define USAGE_OPTS_WIDTH 24
 #define USAGE_GAP         2
 
-int usage_with_options_internal(const char * const *usagestr,
+static int usage_with_options_internal(const char * const *usagestr,
 				const struct option *opts, int full)
 {
 	if (!usagestr)

quote.c

@@ -272,8 +272,8 @@ void write_name_quoted(const char *name, FILE *fp, int terminator)
 	fputc(terminator, fp);
 }
 
-extern void write_name_quotedpfx(const char *pfx, size_t pfxlen,
+void write_name_quotedpfx(const char *pfx, size_t pfxlen,
-                                 const char *name, FILE *fp, int terminator)
+			  const char *name, FILE *fp, int terminator)
 {
 	int needquote = 0;
 

remote.c

@@ -307,7 +307,7 @@ static void read_branches_file(struct remote *remote)
 		strbuf_addstr(&branch, "HEAD:");
 	}
 	add_url_alias(remote, p);
-	add_fetch_refspec(remote, strbuf_detach(&branch, 0));
+	add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 	/*
 	 * Cogito compatible push: push current HEAD to remote #branch
 	 * (master if missing)
@@ -318,7 +318,7 @@ static void read_branches_file(struct remote *remote)
 		strbuf_addf(&branch, ":refs/heads/%s", frag);
 	else
 		strbuf_addstr(&branch, ":refs/heads/master");
-	add_push_refspec(remote, strbuf_detach(&branch, 0));
+	add_push_refspec(remote, strbuf_detach(&branch, NULL));
 	remote->fetch_tags = 1; /* always auto-follow */
 }
 
@@ -1119,7 +1119,7 @@ int match_refs(struct ref *src, struct ref **dst,
 	int send_all = flags & MATCH_REFS_ALL;
 	int send_mirror = flags & MATCH_REFS_MIRROR;
 	int errs;
-	static const char *default_refspec[] = { ":", 0 };
+	static const char *default_refspec[] = { ":", NULL };
 	struct ref **dst_tail = tail_ref(dst);
 
 	if (!nr_refspec) {

test-parse-options.c

@@ -9,7 +9,7 @@ static int verbose = 0, dry_run = 0, quiet = 0;
 static char *string = NULL;
 static char *file = NULL;
 
-int length_callback(const struct option *opt, const char *arg, int unset)
+static int length_callback(const struct option *opt, const char *arg, int unset)
 {
 	printf("Callback: \"%s\", %d\n",
 		(arg ? arg : "not set"), unset);
@@ -20,7 +20,7 @@ int length_callback(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
-int number_callback(const struct option *opt, const char *arg, int unset)
+static int number_callback(const struct option *opt, const char *arg, int unset)
 {
 	*(int *)opt->value = strtol(arg, NULL, 10);
 	return 0;

unpack-trees.c

@@ -140,7 +140,7 @@ static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_option
 	return call_unpack_fn(src, o);
 }
 
-int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
+static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
 {
 	int i;
 	struct tree_desc t[MAX_UNPACK_TREES];

wt-status.c

@@ -13,7 +13,7 @@
 
 int wt_status_relative_paths = 1;
 int wt_status_use_color = -1;
-int wt_status_submodule_summary;
+static int wt_status_submodule_summary;
 static char wt_status_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_NORMAL, /* WT_STATUS_HEADER */
 	GIT_COLOR_GREEN,  /* WT_STATUS_UPDATED */