string parameter values show as null when debugging a procedure (4268167)

When debugging a procedure using the schema browser by either hovering the mouse cursor over the parameter or adding watches to a line, the string value for a parameter is displaying as null. Only the numeric value for parameters is displayed.

EXAMPLE

procedure innerproc(p1 number, p2 nvarchar2)
is
    num number;
    str nvarchar2(1000);
begin
    num := p1 * 2;
    str := p2 || ' received';
   
    dbms_output.put_line('num: ' || num);
    dbms_output.put_line('str: ' || str);
end;
/

procedure outerproc
is
    par1 number;
    par2 nvarchar2(100);
begin
    par1 := 10;
    par2 := 'one hundred';
   
    innerproc(par1, par2);
end;
/

Steps to reproduce:

1. Debugging outerproc.
2. Trace into call to innerproc
3. Inside the innerproc procedure, try to get the value of p1 and p2, either by hovering the mouse cursor or adding them as watches
Expected: the value for both parameters should be displayed
Actual: Only the numeric value (p1) is displayed. The string one (p2) is shown as empty.

This has been identified as a product defect. The issue is caused by the datatype being used in the procedure.

WORKAROUND

Change the datatype used in the procedure from nvarchar2 to varchar2 datatype.

STATUS

Waiting for fix in a future release of Toad for Oracle