MySQL Bugs: #10202: Potential memory leak in make_empty

Bug #10202	Potential memory leak in make_empty_rec
Submitted:	27 Apr 2005 13:41	Modified:	29 Apr 2005 14:04
Reporter:	Mikael Ronström	Email Updates:
Status:	Won't fix	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	5.0-bk (2005-02-04)	OS:	MacOS (Mac OS X 10.3)
Assigned to:	Michael Widenius	CPU Architecture:	Any

Description:
In make_empty_rec there is an obvious memory leak when returning
from the routine in error

How to repeat:
Found by code review, don't know how to repeat

Suggested fix:
Code before fix:

    if (field->def &&
	(regfield->real_type() != FIELD_TYPE_YEAR ||
	 field->def->val_int() != 0))
    {
      if (field->def->save_in_field(regfield, 1))
      {
        my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name);
        error= 1;
        goto err;
      }
    }

Fixed code:

    if (field->def &&
	(regfield->real_type() != FIELD_TYPE_YEAR ||
	 field->def->val_int() != 0))
    {
      if (field->def->save_in_field(regfield, 1))
      {
        my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name);
        error= 1;
        delete regfield; //To avoid memory leak
        goto err;
      }
    }

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/24449

This is not a bug as regfield is allocated with sql_alloc() and thus doesn't have to be freed.
I have now deleted 'delete regfield' from the source and added a comment instead.