Remove redundant null pointer checks before free()

Per applicable standards, free() with a null pointer is a no-op.
Systems that don't observe that are ancient and no longer relevant.
Some PostgreSQL code already required this behavior, so this change
does not introduce any new requirements, just makes the code more
consistent.

Discussion: https://www.postgresql.org/message-id/flat/dac5d2d0-98f5-94d9-8e69-46da2413593d%40enterprisedb.com

9 files changed, 26 insertions, 54 deletions

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 9a610d41ad7..088556ab54c 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -288,8 +288,7 @@ BootstrapModeMain(int argc, char *argv[], bool check_only)
 
 					SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
 					free(name);
-					if (value)
-						free(value);
+					free(value);
 					break;
 				}
 			default:
diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index efc53f31353..2d9ab7edceb 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -2020,10 +2020,7 @@ pam_passwd_conv_proc(int num_msg, const struct pam_message **msg,
 fail:
 	/* free up whatever we allocated */
 	for (i = 0; i < num_msg; i++)
-	{
-		if (reply[i].resp != NULL)
-			free(reply[i].resp);
-	}
+		free(reply[i].resp);
 	free(reply);
 
 	return PAM_CONV_ERR;
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index dde4bc25b13..d7257e4056b 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -854,8 +854,7 @@ PostmasterMain(int argc, char *argv[])
 
 					SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
 					free(name);
-					if (value)
-						free(value);
+					free(value);
 					break;
 				}
 
diff --git a/src/backend/regex/regc_pg_locale.c b/src/backend/regex/regc_pg_locale.c
index e1f9df09180..02d462a6597 100644
--- a/src/backend/regex/regc_pg_locale.c
+++ b/src/backend/regex/regc_pg_locale.c
@@ -930,10 +930,8 @@ pg_ctype_get_cache(pg_wc_probefunc probefunc, int cclasscode)
 	 * Failure, clean up
 	 */
 out_of_memory:
-	if (pcc->cv.chrs)
-		free(pcc->cv.chrs);
-	if (pcc->cv.ranges)
-		free(pcc->cv.ranges);
+	free(pcc->cv.chrs);
+	free(pcc->cv.ranges);
 	free(pcc);
 
 	return NULL;
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 8b6b5bbaaab..495cbf20060 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3896,8 +3896,7 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx,
 					}
 					SetConfigOption(name, value, ctx, gucsource);
 					free(name);
-					if (value)
-						free(value);
+					free(value);
 					break;
 				}
 
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index a0490a75224..ea42e70e43b 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -374,26 +374,16 @@ assign_locale_messages(const char *newval, void *extra)
 static void
 free_struct_lconv(struct lconv *s)
 {
-	if (s->decimal_point)
-		free(s->decimal_point);
-	if (s->thousands_sep)
-		free(s->thousands_sep);
-	if (s->grouping)
-		free(s->grouping);
-	if (s->int_curr_symbol)
-		free(s->int_curr_symbol);
-	if (s->currency_symbol)
-		free(s->currency_symbol);
-	if (s->mon_decimal_point)
-		free(s->mon_decimal_point);
-	if (s->mon_thousands_sep)
-		free(s->mon_thousands_sep);
-	if (s->mon_grouping)
-		free(s->mon_grouping);
-	if (s->positive_sign)
-		free(s->positive_sign);
-	if (s->negative_sign)
-		free(s->negative_sign);
+	free(s->decimal_point);
+	free(s->thousands_sep);
+	free(s->grouping);
+	free(s->int_curr_symbol);
+	free(s->currency_symbol);
+	free(s->mon_decimal_point);
+	free(s->mon_thousands_sep);
+	free(s->mon_grouping);
+	free(s->positive_sign);
+	free(s->negative_sign);
 }
 
 /*
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 55ee5423afb..59124bd9ccb 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -1985,8 +1985,7 @@ set_syslog_parameters(const char *ident, int facility)
 			closelog();
 			openlog_done = false;
 		}
-		if (syslog_ident)
-			free(syslog_ident);
+		free(syslog_ident);
 		syslog_ident = strdup(ident);
 		/* if the strdup fails, we will cope in write_syslog() */
 		syslog_facility = facility;
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index b25bd0e5838..eb43b2c5e57 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -417,8 +417,7 @@ SetDataDir(const char *dir)
 	/* If presented path is relative, convert to absolute */
 	new = make_absolute_path(dir);
 
-	if (DataDir)
-		free(DataDir);
+	free(DataDir);
 	DataDir = new;
 }
 
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f640468f113..0328029d430 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -5483,8 +5483,7 @@ build_guc_variables(void)
 	for (i = 0; ConfigureNamesEnum[i].gen.name; i++)
 		guc_vars[num_vars++] = &ConfigureNamesEnum[i].gen;
 
-	if (guc_variables)
-		free(guc_variables);
+	free(guc_variables);
 	guc_variables = guc_vars;
 	num_guc_variables = num_vars;
 	size_guc_variables = size_vars;
@@ -6880,8 +6879,7 @@ ReportGUCOption(struct config_generic *record)
 		 * set last_reported to NULL and thereby possibly make a duplicate
 		 * report later.
 		 */
-		if (record->last_reported)
-			free(record->last_reported);
+		free(record->last_reported);
 		record->last_reported = strdup(val);
 	}
 
@@ -8356,8 +8354,7 @@ set_config_sourcefile(const char *name, char *sourcefile, int sourceline)
 		return;
 
 	sourcefile = guc_strdup(elevel, sourcefile);
-	if (record->sourcefile)
-		free(record->sourcefile);
+	free(record->sourcefile);
 	record->sourcefile = sourcefile;
 	record->sourceline = sourceline;
 }
@@ -8877,8 +8874,7 @@ AlterSystemSetConfigFile(AlterSystemStmt *altersysstmt)
 
 			if (record->vartype == PGC_STRING && newval.stringval != NULL)
 				free(newval.stringval);
-			if (newextra)
-				free(newextra);
+			free(newextra);
 
 			/*
 			 * We must also reject values containing newlines, because the
@@ -11225,12 +11221,9 @@ RestoreGUCState(void *gucstate)
 		 * pointers.
 		 */
 		Assert(gconf->stack == NULL);
-		if (gconf->extra)
-			free(gconf->extra);
-		if (gconf->last_reported)	/* probably can't happen */
-			free(gconf->last_reported);
-		if (gconf->sourcefile)
-			free(gconf->sourcefile);
+		free(gconf->extra);
+		free(gconf->last_reported);
+		free(gconf->sourcefile);
 		switch (gconf->vartype)
 		{
 			case PGC_BOOL:
@@ -11261,8 +11254,7 @@ RestoreGUCState(void *gucstate)
 				{
 					struct config_string *conf = (struct config_string *) gconf;
 
-					if (*conf->variable)
-						free(*conf->variable);
+					free(*conf->variable);
 					if (conf->reset_val && conf->reset_val != *conf->variable)
 						free(conf->reset_val);
 					if (conf->reset_extra && conf->reset_extra != gconf->extra)