Description:
------------
i'm sorry if this bug report sounds strange, but this is a very strange bug. if it is indeed a bug. a problem with this is that in order to reproduce the bug you would have to install all the ancestor classes to run the code, but i think you will get a good idea of what is going wrong from my description below. basically, this method is part of a DBSelectQuery class that is just a convenience class for building database queries on the fly. The particular method in question is being used in many many other places without errors.

Reproduce code:
---------------
        /**
        * Add a clause to this query
        * @param clause - a DBClause object
        */
        function setClause($db_clause)
        {
            if($db_clause!="")
            {
                $str = $db_clause->toString();
                $this->clause = $str;
            }
        }

Expected result:
----------------
the expected result would be that the member variable 'clause' of the query object would now have the value of the $db_clause object's toString() method.

Actual result:
--------------
if the code is executed as it is above, i get the error:

Fatal error: Call to a member function on a non-object in /usr/home/iain/public_html/sitekitchen/classes/db/dbselectquery.class.inc on line 101

Line 101 is the line with the call:

$str = $db_clause->toString();

So one would assume that $db_clause is somehow not an object. However, if i comment out the line that assigns the variable $str to $this->clause, then there is no error. ie. the code now looks like this:

        /**
        * Add a clause to this query
        * @param clause - a DBClause object
        */
        function setClause($db_clause)
        {
            if($db_clause!="")
            {
                $str = $db_clause->toString();
echo($str);
                //$this->clause = $str;
            }
        }

And i get the following printed out to the screen:

WHERE functionid = '34' 

which is the expected result of the $db_clause object's toString() method, so it is clearly an object.

Please bare in mind here, that the 'Call to a member function on a non-object" error is _not_ occuring on the line that i have commented out above. Commenting out this line prevents the error from occuring in the _previous_ line!!!

also, if i assign some other random string to $this->clause, ie. the code now looks like this:

        /**
        * Add a clause to this query
        * @param clause - a DBClause object
        */
        function setClause($db_clause)
        {
            if($db_clause!="")
            {
                $str = $db_clause->toString();
echo($str);
                $this->clause = "some random string";
            }
        }

then the code is fine (apart from the fact that the database query doesn't work because it has the words "some random string" instead of a where clause!)

i am also able to assign the variable $str to some other random variable, ie:

        /**
        * Add a clause to this query
        * @param clause - a DBClause object
        */
        function setClause($db_clause)
        {
            if($db_clause!="")
            {
                $str = $db_clause->toString();
                $some_random_variable = $str;
echo($str."<br>".$some_random_variable);
                $this->clause = "some random string";
            }
        }

this gives the expected output:

WHERE functionid = '34'
WHERE functionid = '34'

i seriously feel like i am taking crazy pills. if you need some more info, let me know.