Fix select @@ bool parameter bug.

src/common/backend/parser/parse_coerce.cpp

@@ -3137,7 +3137,7 @@ Const* setValueToConstExpr(SetVariableExpr* set)
         case PGC_BOOL:
             {
                 bool variable_bool = false;
-                if (strcmp(variable_str,"true") || strcmp(variable_str,"on")) {
+                if (strcmp(variable_str, "true") == 0 || strcmp(variable_str,"on") == 0) {
                     variable_bool = true;
                 }
                 val = BoolGetDatum(variable_bool);

src/test/regress/input/set_system_variables_test.source

@@ -110,6 +110,7 @@ set @@session.enable_broadcast = on;
 set @@session.enable_broadcast = default;
 set @@enable_broadcast = (1 = 1);
 set @@enable_broadcast = (true = true);
+select @@enable_broadcast;
 set @@enable_broadcast = (true = false);
 
 select @@enable_broadcast;
@@ -298,4 +299,4 @@ drop database if exists test_set;
 \! @abs_bindir@/gs_guc reload -Z datanode -D @abs_srcdir@/tmp_check/datanode1 -c "enable_set_variable_b_format=off" >/dev/null 2>&1
 \! sleep 1
 
-show enable_set_variable_b_format;
+show enable_set_variable_b_format;

src/test/regress/output/set_system_variables_test.source

@@ -237,23 +237,29 @@ set @@session.enable_broadcast = on;
 set @@session.enable_broadcast = default;
 set @@enable_broadcast = (1 = 1);
 set @@enable_broadcast = (true = true);
-set @@enable_broadcast = (true = false);
 select @@enable_broadcast;
  ?column? 
 ----------
  t
 (1 row)
 
+set @@enable_broadcast = (true = false);
+select @@enable_broadcast;
+ ?column? 
+----------
+ f
+(1 row)
+
 select @@session.enable_broadcast;
  ?column? 
 ----------
- t
+ f
 (1 row)
 
 select @@session.enable_broadcast = 'true';
  ?column? 
 ----------
- t
+ f
 (1 row)
 
 set global most_available_sync = t;