[fdo][FDO123][New] Invalid cast between unrelated types in the FdoRdbmsMySqlCon...

[Mateusz Loskot]

You can view the artifact detail at the following URL:

    https://fdo.osgeo.org/servlets/Scarab/id/FDO123

Type
 Defect

Artifact ID
 FDO123 (Invalid cast between unrelated types in the FdoRdbmsMySqlConnectionInfo class)

Reported by
 Mateusz Loskot
 mloskot (mateusz at loskot.net)

New artifact details:
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- OS Distribution and Version set to new value
  Ubuntu 6.06
- Summary set to new value
  Invalid cast between unrelated types in the FdoRdbmsMySqlConnectionInfo class
- Artifact created
- Steps to Reproduce set to new value
  Analyse the code of the FdoRdbmsMySqlConnectionInfo::GetConnectionProperties()
and components used inside.
- Description set to new value
  There is invalid cast in the GetConnectionProperties() function member of the FdoRdbmsMySqlConnectionInfo class.

Here I paste its body:

FdoIConnectionPropertyDictionary*
FdoRdbmsMySqlConnectionInfo::GetConnectionProperties()
{
    if (mPropertyDictionary == NULL)
        mPropertyDictionary = (FdoIConnectionPropertyDictionary *)new FdoRdbmsMySqlConnectionPropertyDictionary(mConnection);
    FDO_SAFE_ADDREF(mPropertyDictionary);
    return mPropertyDictionary;
}

Here, the mConnection data member is casted to FdoIConnectionPropertyDictionary type.
But the type of mConnection is FdoRdbmsMySqlConnectionPropertyDictionary, which in turn is unrelated (not in IS-A relation) to
the target type FdoIConnectionPropertyDictionary.


Here is small case study that illustrates the problem better:

struct A {};
struct B : public A {};
struct C {};

int main()
{
    B* b = new B();

    A* a = 0;
    // OK and recommended
    a = static_cast<A*>(b);
    // OK but not recommended
    a = (A*)b;

    C* c = 0;
    // Invalid and reported
    c = static_cast<C*>(b);
    // Invalid, but not reported, becuse unsafe
    // and bruteforce.
    c = (C*)b;

    return 0;
}

So, casting between FdoIConnectionPropertyDictionary* and FdoRdbmsMySqlConnectionPropertyDictionary*
is like casting between B* and C* in the example above.
- Platform set to new value
  PC
- Artifact Status set to new value
  Unconfirmed
- Operating system set to new value
  Linux
- Defect Severity set to new value
  Critical

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