oleaut32: Copying a NULL BSTR should result in an empty BSTR in VariantCopy.

dlls/oleaut32/tests/vartest.c

@@ -528,6 +528,23 @@ static void test_VariantCopy(void)
            vt | ExtraFlags[i], V_VT(&vDst));
     }
   }
+  
+  /* Test that copying a NULL BSTR results in an empty BSTR */
+  memset(&vDst, 0, sizeof(vDst));
+  V_VT(&vDst) = VT_EMPTY;
+  memset(&vSrc, 0, sizeof(vSrc));
+  V_VT(&vSrc) = VT_BSTR;
+  hres = VariantCopy(&vDst, &vSrc);
+  ok(hres == S_OK, "Copy(NULL BSTR): Failed to copy a NULL BSTR\n");
+  if (hres == S_OK)
+  {
+    ok((V_VT(&vDst) == VT_BSTR) && V_BSTR(&vDst),
+       "Copy(NULL BSTR): should have non-NULL result\n");
+    if ((V_VT(&vDst) == VT_BSTR) && V_BSTR(&vDst))
+    {
+      ok(*V_BSTR(&vDst) == 0, "Copy(NULL BSTR): result not empty\n");
+    }
+  }
 }
 
 /* Determine if a vt is valid for VariantCopyInd() */

dlls/oleaut32/variant.c

@@ -718,15 +718,12 @@ HRESULT WINAPI VariantCopy(VARIANTARG* pvargDest, VARIANTARG* pvargSrc)
       }
       else if (V_VT(pvargSrc) == VT_BSTR)
       {
-        if (V_BSTR(pvargSrc))
-        {
-          V_BSTR(pvargDest) = SysAllocStringByteLen((char*)V_BSTR(pvargSrc), SysStringByteLen(V_BSTR(pvargSrc)));
-          if (!V_BSTR(pvargDest))
-	  {
-	    TRACE("!V_BSTR(pvargDest), SysAllocStringByteLen() failed to allocate %d bytes\n", SysStringByteLen(V_BSTR(pvargSrc)));
-            hres = E_OUTOFMEMORY;
-	  }
-        }
+        V_BSTR(pvargDest) = SysAllocStringByteLen((char*)V_BSTR(pvargSrc), SysStringByteLen(V_BSTR(pvargSrc)));
+        if (!V_BSTR(pvargDest))
+	{
+	  TRACE("!V_BSTR(pvargDest), SysAllocStringByteLen() failed to allocate %d bytes\n", SysStringByteLen(V_BSTR(pvargSrc)));
+          hres = E_OUTOFMEMORY;
+	}
       }
       else if (V_VT(pvargSrc) == VT_RECORD)
       {