Remove useless empty string initializations

This coding style probably stems from the days of shell scripts.
Reviewed-by: Aleksandr Parfenov <a.parfenov@postgrespro.ru>

src/bin/initdb/initdb.c

@@ -118,29 +118,29 @@ static const char *const auth_methods_local[] = {
 static char *share_path = NULL;
 
 /* values to be obtained from arguments */
-static char *pg_data = "";
-static char *encoding = "";
-static char *locale = "";
-static char *lc_collate = "";
-static char *lc_ctype = "";
-static char *lc_monetary = "";
-static char *lc_numeric = "";
-static char *lc_time = "";
-static char *lc_messages = "";
-static const char *default_text_search_config = "";
-static char *username = "";
+static char *pg_data = NULL;
+static char *encoding = NULL;
+static char *locale = NULL;
+static char *lc_collate = NULL;
+static char *lc_ctype = NULL;
+static char *lc_monetary = NULL;
+static char *lc_numeric = NULL;
+static char *lc_time = NULL;
+static char *lc_messages = NULL;
+static const char *default_text_search_config = NULL;
+static char *username = NULL;
 static bool pwprompt = false;
 static char *pwfilename = NULL;
 static char *superuser_password = NULL;
-static const char *authmethodhost = "";
-static const char *authmethodlocal = "";
+static const char *authmethodhost = NULL;
+static const char *authmethodlocal = NULL;
 static bool debug = false;
 static bool noclean = false;
 static bool do_sync = true;
 static bool sync_only = false;
 static bool show_setting = false;
 static bool data_checksums = false;
-static char *xlog_dir = "";
+static char *xlog_dir = NULL;
 
 
 /* internal vars */
@@ -1285,7 +1285,6 @@ bootstrap_template1(void)
 {
 	PG_CMD_DECL;
 	char	  **line;
-	char	   *talkargs = "";
 	char	  **bki_lines;
 	char		headerline[MAXPGPATH];
 	char		buf[64];
@@ -1293,9 +1292,6 @@ bootstrap_template1(void)
 	printf(_("running bootstrap script ... "));
 	fflush(stdout);
 
-	if (debug)
-		talkargs = "-d 5";
-
 	bki_lines = readfile(bki_file);
 
 	/* Check that bki file appears to be of the right version */
@@ -1359,7 +1355,9 @@ bootstrap_template1(void)
 			 "\"%s\" --boot -x1 %s %s %s",
 			 backend_exec,
 			 data_checksums ? "-k" : "",
-			 boot_options, talkargs);
+			 boot_options,
+			 debug ? "-d 5" : "");
+
 
 	PG_CMD_OPEN;
 
@@ -2136,6 +2134,10 @@ check_locale_name(int category, const char *locale, char **canonname)
 	/* save may be pointing at a modifiable scratch variable, so copy it. */
 	save = pg_strdup(save);
 
+	/* for setlocale() call */
+	if (!locale)
+		locale = "";
+
 	/* set the locale with setlocale, to see if it accepts it. */
 	res = setlocale(category, locale);
 
@@ -2223,19 +2225,19 @@ setlocales(void)
 
 	/* set empty lc_* values to locale config if set */
 
-	if (strlen(locale) > 0)
+	if (locale)
 	{
-		if (strlen(lc_ctype) == 0)
+		if (!lc_ctype)
 			lc_ctype = locale;
-		if (strlen(lc_collate) == 0)
+		if (!lc_collate)
 			lc_collate = locale;
-		if (strlen(lc_numeric) == 0)
+		if (!lc_numeric)
 			lc_numeric = locale;
-		if (strlen(lc_time) == 0)
+		if (!lc_time)
 			lc_time = locale;
-		if (strlen(lc_monetary) == 0)
+		if (!lc_monetary)
 			lc_monetary = locale;
-		if (strlen(lc_messages) == 0)
+		if (!lc_messages)
 			lc_messages = locale;
 	}
 
@@ -2310,7 +2312,7 @@ usage(const char *progname)
 static void
 check_authmethod_unspecified(const char **authmethod)
 {
-	if (*authmethod == NULL || strlen(*authmethod) == 0)
+	if (*authmethod == NULL)
 	{
 		authwarning = _("\nWARNING: enabling \"trust\" authentication for local connections\n"
 						"You can change this by editing pg_hba.conf or using the option -A, or\n"
@@ -2367,7 +2369,7 @@ setup_pgdata(void)
 	char	   *pgdata_get_env,
 			   *pgdata_set_env;
 
-	if (strlen(pg_data) == 0)
+	if (!pg_data)
 	{
 		pgdata_get_env = getenv("PGDATA");
 		if (pgdata_get_env && strlen(pgdata_get_env))
@@ -2479,7 +2481,7 @@ setup_locale_encoding(void)
 			   lc_time);
 	}
 
-	if (strlen(encoding) == 0)
+	if (!encoding)
 	{
 		int			ctype_enc;
 
@@ -2589,10 +2591,10 @@ setup_data_file_paths(void)
 void
 setup_text_search(void)
 {
-	if (strlen(default_text_search_config) == 0)
+	if (!default_text_search_config)
 	{
 		default_text_search_config = find_matching_ts_config(lc_ctype);
-		if (default_text_search_config == NULL)
+		if (!default_text_search_config)
 		{
 			printf(_("%s: could not find suitable text search configuration for locale \"%s\"\n"),
 				   progname, lc_ctype);
@@ -2728,7 +2730,7 @@ create_xlog_or_symlink(void)
 	/* form name of the place for the subdirectory or symlink */
 	subdirloc = psprintf("%s/pg_wal", pg_data);
 
-	if (strcmp(xlog_dir, "") != 0)
+	if (xlog_dir)
 	{
 		int			ret;
 
@@ -3131,7 +3133,7 @@ main(int argc, char *argv[])
 	 * Non-option argument specifies data directory as long as it wasn't
 	 * already specified with -D / --pgdata
 	 */
-	if (optind < argc && strlen(pg_data) == 0)
+	if (optind < argc && !pg_data)
 	{
 		pg_data = pg_strdup(argv[optind]);
 		optind++;
@@ -3187,7 +3189,7 @@ main(int argc, char *argv[])
 	setup_bin_paths(argv[0]);
 
 	effective_user = get_id();
-	if (strlen(username) == 0)
+	if (!username)
 		username = effective_user;
 
 	if (strncmp(username, "pg_", 3) == 0)

src/bin/pg_basebackup/pg_basebackup.c

@@ -76,7 +76,7 @@ typedef enum
 /* Global options */
 static char *basedir = NULL;
 static TablespaceList tablespace_dirs = {NULL, NULL};
-static char *xlog_dir = "";
+static char *xlog_dir = NULL;
 static char format = 'p';		/* p(lain)/t(ar) */
 static char *label = "pg_basebackup base backup";
 static bool noclean = false;
@@ -2347,7 +2347,7 @@ main(int argc, char **argv)
 		temp_replication_slot = false;
 	}
 
-	if (strcmp(xlog_dir, "") != 0)
+	if (xlog_dir)
 	{
 		if (format != 'p')
 		{
@@ -2398,7 +2398,7 @@ main(int argc, char **argv)
 	}
 
 	/* Create pg_wal symlink, if required */
-	if (strcmp(xlog_dir, "") != 0)
+	if (xlog_dir)
 	{
 		char	   *linkloc;