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

Author: petere

contrib/pg_stat_statements/pg_stat_statements.c

@@ -809,8 +809,7 @@ pgss_shmem_shutdown(int code, Datum arg)
 			(errcode_for_file_access(),
 			 errmsg("could not write file \"%s\": %m",
 					PGSS_DUMP_FILE ".tmp")));
-	if (qbuffer)
-		free(qbuffer);
+	free(qbuffer);
 	if (file)
 		FreeFile(file);
 	unlink(PGSS_DUMP_FILE ".tmp");
@@ -1657,8 +1656,7 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 			pgss->extent != extent ||
 			pgss->gc_count != gc_count)
 		{
-			if (qbuffer)
-				free(qbuffer);
+			free(qbuffer);
 			qbuffer = qtext_load_file(&qbuffer_size);
 		}
 	}
@@ -1842,8 +1840,7 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 
 	LWLockRelease(pgss->lock);
 
-	if (qbuffer)
-		free(qbuffer);
+	free(qbuffer);
 }
 
 /* Number of output arguments (columns) for pg_stat_statements_info */
@@ -2446,8 +2443,7 @@ gc_qtexts(void)
 	/* clean up resources */
 	if (qfile)
 		FreeFile(qfile);
-	if (qbuffer)
-		free(qbuffer);
+	free(qbuffer);
 
 	/*
 	 * Since the contents of the external file are now uncertain, mark all

contrib/uuid-ossp/uuid-ossp.c

@@ -292,8 +292,7 @@ uuid_generate_internal(int v, unsigned char *ns, const char *ptr, int len)
 						if (ptr && len <= 36)
 							strcpy(strbuf + (36 - len), ptr);
 					}
-					if (str)
-						free(str);
+					free(str);
 				}
 
 				if (status != uuid_s_ok)
@@ -366,8 +365,7 @@ uuid_generate_internal(int v, unsigned char *ns, const char *ptr, int len)
 				if (status == uuid_s_ok)
 					strlcpy(strbuf, str, 37);
 
-				if (str)
-					free(str);
+				free(str);
 
 				if (status != uuid_s_ok)
 					ereport(ERROR,

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:

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;

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;
 				}
 

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;

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;
 				}
 

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);
 }
 
 /*

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;

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;
 }