Bug#34731: highest possible value for INT erroneously filtered by WHERE

WHERE f1 < n ignored row if f1 was indexed integer column and
f1 = TYPE_MAX ^ n = TYPE_MAX+1. The latter value when treated
as TYPE overflowed (obviously). This was not handled, it is now.


mysql-test/r/range.result:
  show that on an index int column, we no longer disregard
  a field val of TYPE_MAX in SELECT ... WHERE ... < TYPE_MAX+1
mysql-test/t/range.test:
  show that on an index int column, we no longer disregard
  a field val of TYPE_MAX in SELECT ... WHERE ... < TYPE_MAX+1
sql/opt_range.cc:
  Handle overflowing of int-types in range-optimizer.
  Unfortunately requires re-indentation of entire block.
  Overflow (err == 1) was handled, but only if
  field->cmp_type() != value->result_type(), which it
  just wasn't in our case.

1 files changed, 54 insertions, 36 deletions

diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index a8cf0f67635..c3eddbd0abf 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -4405,52 +4405,70 @@ get_mm_leaf(PARAM *param, COND *conf_func, Field *field, KEY_PART *key_part,
        field->type() == FIELD_TYPE_DATETIME))
     field->table->in_use->variables.sql_mode|= MODE_INVALID_DATES;
   err= value->save_in_field_no_warnings(field, 1);
-  if (err > 0 && field->cmp_type() != value->result_type())
+  if (err > 0)
   {
-    if ((type == Item_func::EQ_FUNC || type == Item_func::EQUAL_FUNC) &&
-	value->result_type() == item_cmp_type(field->result_type(),
-                                              value->result_type()))
-
+    if (field->cmp_type() != value->result_type())
     {
-      tree= new (alloc) SEL_ARG(field, 0, 0);
-      tree->type= SEL_ARG::IMPOSSIBLE;
-      goto end;
-    }
-    else
-    {
-      /*
-        TODO: We should return trees of the type SEL_ARG::IMPOSSIBLE
-        for the cases like int_field > 999999999999999999999999 as well.
-      */
-      tree= 0;
-      if (err == 3 && field->type() == FIELD_TYPE_DATE && 
-          (type == Item_func::GT_FUNC || type == Item_func::GE_FUNC || 
-           type == Item_func::LT_FUNC || type == Item_func::LE_FUNC) )
+      if ((type == Item_func::EQ_FUNC || type == Item_func::EQUAL_FUNC) &&
+          value->result_type() == item_cmp_type(field->result_type(),
+                                                value->result_type()))
+      {
+        tree= new (alloc) SEL_ARG(field, 0, 0);
+        tree->type= SEL_ARG::IMPOSSIBLE;
+        goto end;
+      }
+      else
       {
         /*
-          We were saving DATETIME into a DATE column, the conversion went ok
-          but a non-zero time part was cut off.
+          TODO: We should return trees of the type SEL_ARG::IMPOSSIBLE
+          for the cases like int_field > 999999999999999999999999 as well.
+        */
+        tree= 0;
+        if (err == 3 && field->type() == FIELD_TYPE_DATE &&
+            (type == Item_func::GT_FUNC || type == Item_func::GE_FUNC ||
+             type == Item_func::LT_FUNC || type == Item_func::LE_FUNC) )
+        {
+          /*
+            We were saving DATETIME into a DATE column, the conversion went ok
+            but a non-zero time part was cut off.
 
-          In MySQL's SQL dialect, DATE and DATETIME are compared as datetime
-          values. Index over a DATE column uses DATE comparison. Changing 
-          from one comparison to the other is possible:
+            In MySQL's SQL dialect, DATE and DATETIME are compared as datetime
+            values. Index over a DATE column uses DATE comparison. Changing 
+            from one comparison to the other is possible:
 
-          datetime(date_col)< '2007-12-10 12:34:55' -> date_col<='2007-12-10'
-          datetime(date_col)<='2007-12-10 12:34:55' -> date_col<='2007-12-10'
+            datetime(date_col)< '2007-12-10 12:34:55' -> date_col<='2007-12-10'
+            datetime(date_col)<='2007-12-10 12:34:55' -> date_col<='2007-12-10'
 
-          datetime(date_col)> '2007-12-10 12:34:55' -> date_col>='2007-12-10'
-          datetime(date_col)>='2007-12-10 12:34:55' -> date_col>='2007-12-10'
+            datetime(date_col)> '2007-12-10 12:34:55' -> date_col>='2007-12-10'
+            datetime(date_col)>='2007-12-10 12:34:55' -> date_col>='2007-12-10'
 
-          but we'll need to convert '>' to '>=' and '<' to '<='. This will
-          be done together with other types at the end of this function
-          (grep for field_is_equal_to_item)
-        */
+            but we'll need to convert '>' to '>=' and '<' to '<='. This will
+            be done together with other types at the end of this function
+            (grep for field_is_equal_to_item)
+          */
+        }
+        else
+          goto end;
       }
-      else
-        goto end;
     }
-  } 
-  if (err < 0)
+
+    /*
+      guaranteed at this point:  err > 0; field and const of same type
+      If an integer got bounded (e.g. to within 0..255 / -128..127)
+      for < or >, set flags as for <= or >= (no NEAR_MAX / NEAR_MIN)
+    */
+    else if (err == 1 && field->result_type() == INT_RESULT)
+    {
+      if (type == Item_func::LT_FUNC && (value->val_int() > 0))
+        type = Item_func::LE_FUNC;
+      else if (type == Item_func::GT_FUNC &&
+               !((Field_num*)field)->unsigned_flag &&
+               !((Item_int*)value)->unsigned_flag &&
+               (value->val_int() < 0))
+        type = Item_func::GE_FUNC;
+    }
+  }
+  else if (err < 0)
   {
     field->table->in_use->variables.sql_mode= orig_sql_mode;
     /* This happens when we try to insert a NULL field in a not null column */