BUG#19801: Valgrind error in check_list_constants

Needed some special handling of the case when no_list_values == 0


mysql-test/r/partition.result:
  Added a couple of new test cases
mysql-test/t/partition.test:
  Added a couple of new test cases
sql/partition_info.cc:
  Rearranged some code to handle case where no_list_values == 0 which
  happens when one partition with only one value == NULL.
sql/sql_partition.cc:
  Rearranged code to remove compiler warning and also since we
  now have handled the case where no_list_values == 0 in a special
  case before coming here
  Added code for handling the special case where no_list_values == 0

mysql-test/r/partition.result

@@ -757,6 +757,18 @@ insert into t1 values (null);
 select * from t1 where f1 is null;
 f1
 NULL
+select * from t1 where f1 < 1;
+f1
+select * from t1 where f1 <= NULL;
+f1
+select * from t1 where f1 < NULL;
+f1
+select * from t1 where f1 >= NULL;
+f1
+select * from t1 where f1 > NULL;
+f1
+select * from t1 where f1 > 1;
+f1
 drop table t1;
 create table t1 (f1 smallint)
 partition by range (f1) (partition p0 values less than (0));

mysql-test/t/partition.test

@@ -895,6 +895,12 @@ create table t1 (f1 smallint)
 partition by list (f1) (partition p0 values in (null));
 insert into t1 values (null);
 select * from t1 where f1 is null;
+select * from t1 where f1 < 1;
+select * from t1 where f1 <= NULL;
+select * from t1 where f1 < NULL;
+select * from t1 where f1 >= NULL;
+select * from t1 where f1 > NULL;
+select * from t1 where f1 > 1;
 drop table t1;
 
 create table t1 (f1 smallint)

sql/partition_info.cc

@@ -612,7 +612,8 @@ bool partition_info::check_list_constants()
       no_list_values++;
   } while (++i < no_parts);
   list_func_it.rewind();
-  list_array= (LIST_PART_ENTRY*)sql_alloc(no_list_values*sizeof(LIST_PART_ENTRY));
+  list_array= (LIST_PART_ENTRY*)sql_alloc((no_list_values+1) *
+                                          sizeof(LIST_PART_ENTRY));
   if (unlikely(list_array == NULL))
   {
     mem_alloc_error(no_list_values * sizeof(LIST_PART_ENTRY));
@@ -631,25 +632,29 @@ bool partition_info::check_list_constants()
     }
   } while (++i < no_parts);
 
-  qsort((void*)list_array, no_list_values, sizeof(LIST_PART_ENTRY), 
-        &list_part_cmp);
-
-  not_first= FALSE;
-  i= prev_value= 0; //prev_value initialised to quiet compiler
-  do
+  if (no_list_values)
   {
-    curr_value= list_array[i].list_value;
-    if (likely(!not_first || prev_value != curr_value))
-    {
-      prev_value= curr_value;
-      not_first= TRUE;
-    }
-    else
+    qsort((void*)list_array, no_list_values, sizeof(LIST_PART_ENTRY), 
+          &list_part_cmp);
+ 
+    not_first= FALSE;
+    i= prev_value= 0; //prev_value initialised to quiet compiler
+    do
     {
-      my_error(ER_MULTIPLE_DEF_CONST_IN_LIST_PART_ERROR, MYF(0));
-      goto end;
-    }
-  } while (++i < no_list_values);
+      DBUG_ASSERT(i < no_list_values);
+      curr_value= list_array[i].list_value;
+      if (likely(!not_first || prev_value != curr_value))
+      {
+        prev_value= curr_value;
+        not_first= TRUE;
+      }
+      else
+      {
+        my_error(ER_MULTIPLE_DEF_CONST_IN_LIST_PART_ERROR, MYF(0));
+        goto end;
+      }
+    } while (++i < no_list_values);
+  }
   result= FALSE;
 end:
   DBUG_RETURN(result);

sql/sql_partition.cc

@@ -2257,8 +2257,8 @@ static uint32 get_part_id_linear_key(partition_info *part_info,
 
 
 int get_partition_id_list(partition_info *part_info,
-                           uint32 *part_id,
-                           longlong *func_value)
+                          uint32 *part_id,
+                          longlong *func_value)
 {
   LIST_PART_ENTRY *list_array= part_info->list_array;
   int list_index;
@@ -2351,7 +2351,8 @@ uint32 get_list_array_idx_for_endpoint(partition_info *part_info,
   uint min_list_index= 0, max_list_index= part_info->no_list_values - 1;
   /* Get the partitioning function value for the endpoint */
   longlong part_func_value= part_val_int(part_info->part_expr);
-  while (max_list_index >= min_list_index)
+  DBUG_ASSERT(part_info->no_list_values);
+  do
   {
     list_index= (max_list_index + min_list_index) >> 1;
     list_value= list_array[list_index].list_value;
@@ -2367,7 +2368,7 @@ uint32 get_list_array_idx_for_endpoint(partition_info *part_info,
     {
       DBUG_RETURN(list_index + test(left_endpoint ^ include_endpoint));
     }
-  }
+  } while (max_list_index >= min_list_index);
 notfound:
   if (list_value < part_func_value)
     list_index++;
@@ -6194,6 +6195,18 @@ int get_part_iter_for_interval_via_mapping(partition_info *part_info,
     part_iter->get_next= get_next_partition_id_list;
     part_iter->part_info= part_info;
     part_iter->ret_null_part= part_iter->ret_null_part_orig= FALSE;
+    if (max_endpoint_val == 0)
+    {
+      /*
+        We handle this special case without optimisations since it is
+        of little practical value but causes a great number of complex
+        checks later in the code.
+      */
+      part_iter->part_nums.start= part_iter->part_nums.end= 0;
+      part_iter->part_nums.cur= 0;
+      part_iter->ret_null_part= part_iter->ret_null_part_orig= TRUE;
+      return -1;
+    }
   }
   else
     DBUG_ASSERT(0);