Alex Villacís Lasso wrote:
I would like to draw attention to bug 4502. This bug can cause any VB
application to crash when the DatePicker control is used, and an
attempt is made to assign a date value in VB code. Even though I found
this bug while testing an application I wrote, this might not be
specific to this application. It is only recently that I have some
time to dedicate to this bug, but I would like somebody to comment on
this.
When the sample application is run with WINEDEBUG=ole,variant, the
failing invocation looks like this:
trace:ole:ITypeInfo_fnInvoke
(0x7fdd5440)(0x7fd9f61c,id=20,flags=0x00000004,0x7fa3ee8c,(nil),0x7fa3ee6c,0x7fa3ee9c)
trace:ole:dump_DispParms args=1 named args=1
trace:ole:dump_Variant 0x7fa3eef4->{VT_DATE(38788,0x7fa3ec7c)
trace:variant:VarUdateFromDate (38788,0x00000000,0x7fa3ec36)
trace:ole:dump_Variant ,2006/03/12 00:00:00}
trace:ole:ITypeInfo_fnInvoke invoking:
L"Value"(1)
parm0: L"Value"
memid is 00000014
Param 0:
tdesc.vartype 12 (VT_VARIANT)
u.paramdesc.wParamFlags PARAMFLAG_FIN
u.paramdesc.lpex (nil)
funckind: 1 (pure virtual)
invkind: 4 (property put)
callconv: 4 (stdcall)
oVft: 224
cParamsOpt: 0
wFlags: 3c
elemdescFunc (return value type):
tdesc.vartype 25 (VT_HRESULT)
u.paramdesc.wParamFlags PARAMFLAGS_NONE
u.paramdesc.lpex (nil)
helpstring: L"Returns/sets the current date."
entry: (null)
trace:ole:ITypeInfo_fnInvoke changing args
trace:ole:dump_Variant 0x7fa3eef4->{VT_DATE(38788,0x7fa3ec7c)
trace:variant:VarUdateFromDate (38788,0x00000000,0x7fa3ec36)
trace:ole:dump_Variant ,2006/03/12 00:00:00}
trace:variant:VariantChangeTypeEx
(0x7fdd5520->(VT_DATE),0x7fa3eef4->(VT_DATE),0x00000400,0x0000,VT_VARIANT)
trace:variant:VariantClear (0x7fa3ec40->(VT_EMPTY))
trace:variant:VariantClear (0x7fa3ec30->(VT_EMPTY))
trace:variant:VariantCopyInd
(0x7fa3ec30->(VT_EMPTY),0x7fa3eef4->(VT_DATE))
trace:variant:VariantCopy (0x7fa3ec30->(VT_EMPTY),0x7fa3eef4->(VT_DATE))
trace:variant:VariantClear (0x7fa3ec30->(VT_EMPTY))
trace:variant:VARIANT_Coerce
(0x7fa3ec40->(VT_EMPTY),0x00000400,0x0000,0x7fa3ec30->(VT_DATE),VT_VARIANT)
trace:variant:VariantClear (0x7fa3ec40->(VT_EMPTY))
trace:variant:VariantClear (0x7fa3ec30->(VT_DATE))
trace:variant:VariantChangeTypeEx returning 0x80020005,
0x7fdd5520->(VT_DATE)
err:ole:ITypeInfo_fnInvoke failed to convert param 0 to VT_VARIANT
from VT_DATE
trace:ole:ITypeInfo_fnInvoke -- 0x80020005
The Property Put seems to be declared as taking one VT_VARIANT
parameter, and the VB code supplies a VT_DATE value. Therefore, an
attempt is made to coerce VT_DATE --> VT_VARIANT. However,
VariantChangeTypeEx() does not support conversion of *any* kind of
variant into VT_VARIANT, so the call fails, and this brings down the
application. I was on half a mind to add the VT_VARIANT conversion to
VariantChangeTypeEx() myself, but then I checked the tests for this
operation, and it seems that the absence of support for VT_VARIANT is
actually expected (unless I am misreading the code). Therefore, one of
the following two things is happening:
1) There is some error in the reading of the typelib, since a Property
Put should not have a VT_VARIANT parameter in the first place.
2) ITypeInfo::Invoke should do the VT_VARIANT conversion itself,
precisely because VariantChangeTypeEx() won't do it.
I am inclined to the second option, but I want to hear some comment
before attempting to create a patch.
Alex Villacís Lasso
After some digging, I found that bugs 4370 and 4573 seem to expose the
same problem. The root cause (in bug 4370) seems to be a patch by Robert
Shearman that rewrites ITypeInfo::Invoke to use VariantChangeTypeEx
(commit at
http://source.winehq.org/git/?p=wine.git;a=commit;h=8cf5373f60aca5345a0c55df2711a9f0b73b8133).
Saved me the trouble of the regression testing.
Alex Villacís Lasso
