MDEV-19317 TEXT column accepts too long literals as a default value

Adding new virtual methods in Field:
- make_empty_rec_store_default_value()
- make_empty_rec_reset()

This simplifies the logic for every Field type,
and makes the code more friendly to pluggable data types.

1 files changed, 29 insertions, 32 deletions

diff --git a/sql/unireg.cc b/sql/unireg.cc
index 1d6bb0cdfce..02d876e1455 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -974,13 +974,36 @@ static bool pack_fields(uchar **buff_arg, List<Create_field> &create_fields,
   DBUG_RETURN(0);
 }
 
+
+static bool make_empty_rec_store_default(THD *thd, Field *regfield,
+                                         Virtual_column_info *default_value)
+{
+  if (default_value && !default_value->flags)
+  {
+    Item *expr= default_value->expr;
+    // may be already fixed if ALTER TABLE
+    if (expr->fix_fields_if_needed(thd, &expr))
+      return true;
+    DBUG_ASSERT(expr == default_value->expr); // Should not change
+    if (regfield->make_empty_rec_store_default_value(thd, expr))
+    {
+      my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name.str);
+      return true;
+    }
+    return false;
+  }
+  regfield->make_empty_rec_reset(thd);
+  return false;
+}
+
+
 /* save an empty record on start of formfile */
 
 static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
 			   List<Create_field> &create_fields,
 			   uint reclength, ulong data_offset)
 {
-  int error= 0;
+  int error= false;
   uint null_count;
   uchar *null_pos;
   TABLE table;
@@ -1020,7 +1043,7 @@ static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
                                     field->flags);
     if (!regfield)
     {
-      error= 1;
+      error= true;
       goto err;                                 // End of memory
     }
 
@@ -1037,36 +1060,10 @@ static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
         !f_bit_as_char(field->pack_flag))
       null_count+= field->length & 7;
 
-    if (field->default_value && !field->default_value->flags &&
-        (!(field->flags & BLOB_FLAG) ||
-         field->real_field_type() == MYSQL_TYPE_GEOMETRY))
-    {
-      Item *expr= field->default_value->expr;
-      // may be already fixed if ALTER TABLE
-      int res= expr->fix_fields_if_needed(thd, &expr);
-      if (!res)
-        res= expr->save_in_field(regfield, 1);
-      if (!res && (field->flags & BLOB_FLAG))
-        regfield->reset();
-
-      /* If not ok or warning of level 'note' */
-      if (res != 0 && res != 3)
-      {
-        my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name.str);
-        error= 1;
-        delete regfield; //To avoid memory leak
-        goto err;
-      }
-      delete regfield; //To avoid memory leak
-    }
-    else if (regfield->real_type() == MYSQL_TYPE_ENUM &&
-	     (field->flags & NOT_NULL_FLAG))
-    {
-      regfield->set_notnull();
-      regfield->store((longlong) 1, TRUE);
-    }
-    else
-      regfield->reset();
+    error= make_empty_rec_store_default(thd, regfield, field->default_value);
+    delete regfield; // Avoid memory leaks
+    if (error)
+      goto err;
   }
   DBUG_ASSERT(data_offset == ((null_count + 7) / 8));