Assertion failure in DBAccess.pas

I am interested in upgrading a suite of software from ODAC v5 to v8.2.8.

One app in particular is causing problems. This application loads one of a set of secondary applications implemented as dlls.

LibHandle := LoadLibrary(PChar(dllname));
if LibHandle <> 0 then
begin
  @showForm := GetProcAddress(LibHandle,'ShowMainDllForm');
  if (@showForm <> nil) then
  begin
    try
      ShowForm(Application.Handle, @FGlobalVars, 1);

The launcher is fine - it has its own database connection, and I can step through the various ODAC units fairly happily.

However, the dll immediately excepts on attempting to open a cursor. The error is an Assertion Failure in the unit DBAccess.pas, called from MemDs.pas. I have stepped through this and have shown that the assertion failure is correct; Assert(FieldDesc is TCRFieldDesc) is receiving a TFieldDesc from MemDS.CreateFieldDefs().

I am stumped. How can it be that one calling method works fine (the launcher app) and the other (the dll) always fails ?

If anyone has experienced difficulties in this area I would appreciate any information, however tenuous it might sound

Solution

We have already fixed this problem. You can either download the latest ODAC version 8.6.12 or modify the line invoking Assert:

in the TCustomDADataSet.GetFieldType method

replace 
  Assert(FieldDesc is TCRFieldDesc);
with
  Assert(IsClass(FieldDesc, TCRFieldDesc));