Merge branch 'ep/maint-equals-null-cocci'

Introduce and apply coccinelle rule to discourage an explicit
comparison between a pointer and NULL, and applies the clean-up to
the maintenance track.

* ep/maint-equals-null-cocci:
  tree-wide: apply equals-null.cocci
  tree-wide: apply equals-null.cocci
  contrib/coccinnelle: add equals-null.cocci

apply.c

@@ -3274,11 +3274,11 @@ static struct patch *in_fn_table(struct apply_state *state, const char *name)
 {
 	struct string_list_item *item;
 
-	if (name == NULL)
+	if (!name)
 		return NULL;
 
 	item = string_list_lookup(&state->fn_table, name);
-	if (item != NULL)
+	if (item)
 		return (struct patch *)item->util;
 
 	return NULL;
@@ -3318,7 +3318,7 @@ static void add_to_fn_table(struct apply_state *state, struct patch *patch)
 	 * This should cover the cases for normal diffs,
 	 * file creations and copies
 	 */
-	if (patch->new_name != NULL) {
+	if (patch->new_name) {
 		item = string_list_insert(&state->fn_table, patch->new_name);
 		item->util = patch;
 	}

archive.c

@@ -465,7 +465,7 @@ static void parse_treeish_arg(const char **argv,
 	}
 
 	tree = parse_tree_indirect(&oid);
-	if (tree == NULL)
+	if (!tree)
 		die(_("not a tree object: %s"), oid_to_hex(&oid));
 
 	if (prefix) {

blame.c

@@ -1072,7 +1072,7 @@ static struct blame_entry *blame_merge(struct blame_entry *list1,
 	if (p1->s_lno <= p2->s_lno) {
 		do {
 			tail = &p1->next;
-			if ((p1 = *tail) == NULL) {
+			if (!(p1 = *tail)) {
 				*tail = p2;
 				return list1;
 			}
@@ -1082,15 +1082,15 @@ static struct blame_entry *blame_merge(struct blame_entry *list1,
 		*tail = p2;
 		do {
 			tail = &p2->next;
-			if ((p2 = *tail) == NULL)  {
+			if (!(p2 = *tail))  {
 				*tail = p1;
 				return list1;
 			}
 		} while (p1->s_lno > p2->s_lno);
 		*tail = p1;
 		do {
 			tail = &p1->next;
-			if ((p1 = *tail) == NULL) {
+			if (!(p1 = *tail)) {
 				*tail = p2;
 				return list1;
 			}

branch.c

@@ -466,7 +466,7 @@ static void dwim_branch_start(struct repository *r, const char *start_name,
 		break;
 	}
 
-	if ((commit = lookup_commit_reference(r, &oid)) == NULL)
+	if (!(commit = lookup_commit_reference(r, &oid)))
 		die(_("not a valid branch point: '%s'"), start_name);
 	if (out_real_ref) {
 		*out_real_ref = real_ref;

builtin/bisect--helper.c

@@ -474,7 +474,7 @@ static int bisect_terms(struct bisect_terms *terms, const char *option)
 	if (get_terms(terms))
 		return error(_("no terms defined"));
 
-	if (option == NULL) {
+	if (!option) {
 		printf(_("Your current terms are %s for the old state\n"
 			 "and %s for the new state.\n"),
 		       terms->term_good, terms->term_bad);

builtin/checkout.c

@@ -834,7 +834,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
 			if (ret)
 				return ret;
 			o.ancestor = old_branch_info->name;
-			if (old_branch_info->name == NULL) {
+			if (!old_branch_info->name) {
 				strbuf_add_unique_abbrev(&old_commit_shortname,
 							 &old_branch_info->commit->object.oid,
 							 DEFAULT_ABBREV);

builtin/clone.c

@@ -1106,12 +1106,12 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	 * apply the remote name provided by --origin only after this second
 	 * call to git_config, to ensure it overrides all config-based values.
 	 */
-	if (option_origin != NULL) {
+	if (option_origin) {
 		free(remote_name);
 		remote_name = xstrdup(option_origin);
 	}
 
-	if (remote_name == NULL)
+	if (!remote_name)
 		remote_name = xstrdup("origin");
 
 	if (!valid_remote_name(remote_name))

builtin/commit.c

@@ -861,7 +861,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	}
 
 	s->fp = fopen_for_writing(git_path_commit_editmsg());
-	if (s->fp == NULL)
+	if (!s->fp)
 		die_errno(_("could not open '%s'"), git_path_commit_editmsg());
 
 	/* Ignore status.displayCommentPrefix: we do need comments in COMMIT_EDITMSG. */

builtin/diff.c

@@ -352,7 +352,7 @@ static void symdiff_prepare(struct rev_info *rev, struct symdiff *sym)
 			othercount++;
 			continue;
 		}
-		if (map == NULL)
+		if (!map)
 			map = bitmap_new();
 		bitmap_set(map, i);
 	}

builtin/gc.c

@@ -446,7 +446,7 @@ static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 			fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
 			/* be gentle to concurrent "gc" on remote hosts */
 			(strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
-		if (fp != NULL)
+		if (fp)
 			fclose(fp);
 		if (should_exit) {
 			if (fd >= 0)
@@ -2238,7 +2238,7 @@ static int systemd_timer_write_unit_templates(const char *exec_path)
 		goto error;
 	}
 	file = fopen_or_warn(filename, "w");
-	if (file == NULL)
+	if (!file)
 		goto error;
 
 	unit = "# This file was created and is maintained by Git.\n"
@@ -2267,7 +2267,7 @@ static int systemd_timer_write_unit_templates(const char *exec_path)
 
 	filename = xdg_config_home_systemd("[email protected]");
 	file = fopen_or_warn(filename, "w");
-	if (file == NULL)
+	if (!file)
 		goto error;
 
 	unit = "# This file was created and is maintained by Git.\n"

builtin/index-pack.c

@@ -1942,11 +1942,11 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 	free(objects);
 	strbuf_release(&index_name_buf);
 	strbuf_release(&rev_index_name_buf);
-	if (pack_name == NULL)
+	if (!pack_name)
 		free((void *) curr_pack);
-	if (index_name == NULL)
+	if (!index_name)
 		free((void *) curr_index);
-	if (rev_index_name == NULL)
+	if (!rev_index_name)
 		free((void *) curr_rev_index);
 
 	/*

builtin/log.c

@@ -1030,7 +1030,7 @@ static int open_next_file(struct commit *commit, const char *subject,
 	if (!quiet)
 		printf("%s\n", filename.buf + outdir_offset);
 
-	if ((rev->diffopt.file = fopen(filename.buf, "w")) == NULL) {
+	if (!(rev->diffopt.file = fopen(filename.buf, "w"))) {
 		error_errno(_("cannot open patch file %s"), filename.buf);
 		strbuf_release(&filename);
 		return -1;

builtin/ls-remote.c

@@ -114,7 +114,7 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 	}
 
 	transport = transport_get(remote, NULL);
-	if (uploadpack != NULL)
+	if (uploadpack)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK, uploadpack);
 	if (server_options.nr)
 		transport->server_options = &server_options;

builtin/mailsplit.c

@@ -120,7 +120,7 @@ static int populate_maildir_list(struct string_list *list, const char *path)
 	for (sub = subs; *sub; ++sub) {
 		free(name);
 		name = xstrfmt("%s/%s", path, *sub);
-		if ((dir = opendir(name)) == NULL) {
+		if (!(dir = opendir(name))) {
 			if (errno == ENOENT)
 				continue;
 			error_errno("cannot opendir %s", name);

builtin/pack-redundant.c

@@ -101,7 +101,7 @@ static inline struct llist_item *llist_insert(struct llist *list,
 	oidread(&new_item->oid, oid);
 	new_item->next = NULL;
 
-	if (after != NULL) {
+	if (after) {
 		new_item->next = after->next;
 		after->next = new_item;
 		if (after == list->back)
@@ -157,7 +157,7 @@ static inline struct llist_item * llist_sorted_remove(struct llist *list, const
 		if (cmp > 0) /* not in list, since sorted */
 			return prev;
 		if (!cmp) { /* found */
-			if (prev == NULL) {
+			if (!prev) {
 				if (hint != NULL && hint != list->front) {
 					/* we don't know the previous element */
 					hint = NULL;
@@ -219,7 +219,7 @@ static struct pack_list * pack_list_difference(const struct pack_list *A,
 	struct pack_list *ret;
 	const struct pack_list *pl;
 
-	if (A == NULL)
+	if (!A)
 		return NULL;
 
 	pl = B;
@@ -317,7 +317,7 @@ static size_t get_pack_redundancy(struct pack_list *pl)
 	struct pack_list *subset;
 	size_t ret = 0;
 
-	if (pl == NULL)
+	if (!pl)
 		return 0;
 
 	while ((subset = pl->next)) {
@@ -611,7 +611,7 @@ int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
 		while (*(argv + i) != NULL)
 			add_pack_file(*(argv + i++));
 
-	if (local_packs == NULL)
+	if (!local_packs)
 		die("Zero packs found!");
 
 	load_all_objects();

builtin/receive-pack.c

@@ -1664,7 +1664,7 @@ static void check_aliased_update_internal(struct command *cmd,
 	}
 	dst_name = strip_namespace(dst_name);
 
-	if ((item = string_list_lookup(list, dst_name)) == NULL)
+	if (!(item = string_list_lookup(list, dst_name)))
 		return;
 
 	cmd->skip_update = 1;
@@ -2538,7 +2538,7 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 			   PACKET_READ_CHOMP_NEWLINE |
 			   PACKET_READ_DIE_ON_ERR_PACKET);
 
-	if ((commands = read_head_info(&reader, &shallow)) != NULL) {
+	if ((commands = read_head_info(&reader, &shallow))) {
 		const char *unpack_status = NULL;
 		struct string_list push_options = STRING_LIST_INIT_DUP;
 

builtin/replace.c

@@ -72,7 +72,7 @@ static int list_replace_refs(const char *pattern, const char *format)
 {
 	struct show_data data;
 
-	if (pattern == NULL)
+	if (!pattern)
 		pattern = "*";
 	data.pattern = pattern;
 

builtin/rev-parse.c

@@ -476,7 +476,7 @@ static int cmd_parseopt(int argc, const char **argv, const char *prefix)
 
 		/* name(s) */
 		s = strpbrk(sb.buf, flag_chars);
-		if (s == NULL)
+		if (!s)
 			s = help;
 
 		if (s - sb.buf == 1) /* short option only */

builtin/shortlog.c

@@ -81,7 +81,7 @@ static void insert_one_record(struct shortlog *log,
 		format_subject(&subject, oneline, " ");
 		buffer = strbuf_detach(&subject, NULL);
 
-		if (item->util == NULL)
+		if (!item->util)
 			item->util = xcalloc(1, sizeof(struct string_list));
 		string_list_append(item->util, buffer);
 	}

builtin/tag.c

@@ -364,15 +364,15 @@ static void create_reflog_msg(const struct object_id *oid, struct strbuf *sb)
 		strbuf_addstr(sb, "object of unknown type");
 		break;
 	case OBJ_COMMIT:
-		if ((buf = read_object_file(oid, &type, &size)) != NULL) {
+		if ((buf = read_object_file(oid, &type, &size))) {
 			subject_len = find_commit_subject(buf, &subject_start);
 			strbuf_insert(sb, sb->len, subject_start, subject_len);
 		} else {
 			strbuf_addstr(sb, "commit object");
 		}
 		free(buf);
 
-		if ((c = lookup_commit_reference(the_repository, oid)) != NULL)
+		if ((c = lookup_commit_reference(the_repository, oid)))
 			strbuf_addf(sb, ", %s", show_date(c->date, 0, DATE_MODE(SHORT)));
 		break;
 	case OBJ_TREE:

combine-diff.c

@@ -195,10 +195,10 @@ static struct lline *coalesce_lines(struct lline *base, int *lenbase,
 	struct lline *baseend, *newend = NULL;
 	int i, j, origbaselen = *lenbase;
 
-	if (newline == NULL)
+	if (!newline)
 		return base;
 
-	if (base == NULL) {
+	if (!base) {
 		*lenbase = lennew;
 		return newline;
 	}

commit-graph.c

@@ -2570,7 +2570,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
 		odb_parents = odb_commit->parents;
 
 		while (graph_parents) {
-			if (odb_parents == NULL) {
+			if (!odb_parents) {
 				graph_report(_("commit-graph parent list for commit %s is too long"),
 					     oid_to_hex(&cur_oid));
 				break;
@@ -2593,7 +2593,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
 			odb_parents = odb_parents->next;
 		}
 
-		if (odb_parents != NULL)
+		if (odb_parents)
 			graph_report(_("commit-graph parent list for commit %s terminates early"),
 				     oid_to_hex(&cur_oid));
 

compat/mingw.c

@@ -1060,7 +1060,7 @@ char *mingw_mktemp(char *template)
 int mkstemp(char *template)
 {
 	char *filename = mktemp(template);
-	if (filename == NULL)
+	if (!filename)
 		return -1;
 	return open(filename, O_RDWR | O_CREAT, 0600);
 }
@@ -2332,7 +2332,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out)
 	static const struct timeval zero;
 	static int atexit_done;
 
-	if (out != NULL)
+	if (out)
 		return errno = EINVAL,
 			error("setitimer param 3 != NULL not implemented");
 	if (!is_timeval_eq(&in->it_interval, &zero) &&
@@ -2361,7 +2361,7 @@ int sigaction(int sig, struct sigaction *in, struct sigaction *out)
 	if (sig != SIGALRM)
 		return errno = EINVAL,
 			error("sigaction only implemented for SIGALRM");
-	if (out != NULL)
+	if (out)
 		return errno = EINVAL,
 			error("sigaction: param 3 != NULL not implemented");
 

compat/mkdir.c

@@ -9,7 +9,7 @@ int compat_mkdir_wo_trailing_slash(const char *dir, mode_t mode)
 	size_t len = strlen(dir);
 
 	if (len && dir[len-1] == '/') {
-		if ((tmp_dir = strdup(dir)) == NULL)
+		if (!(tmp_dir = strdup(dir)))
 			return -1;
 		tmp_dir[len-1] = '\0';
 	}

compat/mmap.c

@@ -13,7 +13,7 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 	}
 
 	start = malloc(length);
-	if (start == NULL) {
+	if (!start) {
 		errno = ENOMEM;
 		return MAP_FAILED;
 	}