### Author:  [@efahl](https://discourse.vtk.org/u/efahl)
#### Post date: [April 7, 2022, 11:32pm UTC](https://discourse.vtk.org/t/vtk-9-1-python-overloaded-method-call-broken/8235/1 "2022-04-07T23:32:50Z")
It appears that `vtkDICOMReader.GetMetaData.Get` overloaded Python methods are broken in vtk 9.1. Tested in both Python 3.9 and 3.10, same result, so not Py-version specific.
I’m building VTK with the remote vtkDICOM module. Had been on 9.0 for a while, wanted to move to 9.1. Everything built as expected, but then the first test I ran showed an error on previously working code.
The usual background boilerplate:
vtk git tag v9.0.1 (shown below as 9.0.7068-EF)
vtk git tag v9.1.0 (shown below as 9.1.7251-EF)
Python 3.9.7 (tags/v3.9.7:1016ef3, Aug 30 2021, 20:19:38) [MSC v.1929 64 bit (AMD64)] on win32
cmake version 3.22.1
Python 3.10.3 (tags/v3.10.3:a342a49, Mar 16 2022, 13:07:40) [MSC v.1929 64 bit (AMD64)] on win32
cmake version 3.22.3
Microsoft Windows [Version 10.0.19043.1586]
– The C compiler identification is MSVC 19.16.27045.0
– The CXX compiler identification is MSVC 19.16.27045.0
cl Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27045 for x64
My minimal reproducer, `overload.py`.
```auto
import vtk
print(vtk.vtkVersion().GetVTKSourceVersion())
reader = vtk.vtkDICOMReader()
reader.SetFileName('tests/images/IM615')
reader.Update()
metadata = reader.GetMetaData()
#print(metadata)
print(metadata.Get(vtk.DC.StudyDescription))
print(metadata.Get(vtk.DC.ImagePositionPatient))
```
I’ve got my own wheel database, so I simply pip-install my local builds.
```auto
> pip install vtk==9.0.1
> py -3.9 overload.py
9.0.7068-EF
LEG LENGTH
0.000000\0.000000\0.000000
```
I get the following error for both `Get` calls, so it’s not unique to one of the `DC` tags.
```auto
> pip install vtk==9.1.0
> py -3.9 overload.py
9.1.7251-EF
Traceback (most recent call last):
File "overload.py", line 12, in
print(metadata.Get(vtk.DC.StudyDescription))
TypeError: arguments do not match any overloaded methods
```
I diff files between 9.0.1 and 9.1.0, first the generated code. `build/CMakeFiles/vtkDICOMPython/vtkDICOMMetaDataPython.cxx` - no diffs in overload table, only substantial diffs appear to be docstrings. Here’s a snippet from that code, identical in VTK 9.0 and 9.1, across both Python 3.9 and 3.10; I think above example is supposed to go through the `s1` variant.
```auto
static PyMethodDef PyvtkDICOMMetaData_Get_Methods[] = {
{nullptr, PyvtkDICOMMetaData_Get_s1, METH_VARARGS,
"@W vtkDICOMTag"},
{nullptr, PyvtkDICOMMetaData_Get_s2, METH_VARARGS,
"@W vtkDICOMTagPath"},
```
Ok, maybe the enumeration type has changed… `Remote/vtkDICOM/Source/vtkDICOMTag.cxx` and `.h` - no changes at all.
I then look at differences in the Python wrapper code, `Wrapping/PythonCore/vtkPythonOverload.cxx` - no changes in overload handling.
My assumption is that there’s something going on in the argument parsing and/or passing before it gets to `vtkPythonOverload::CallMethod`, but I’m sort of stuck there.
Anyone have some clues as to where I might poke to chase this down? @dgobbi?
---
### Author:  [@dgobbi](https://discourse.vtk.org/u/dgobbi)
#### Post date: [April 8, 2022, 5:39am UTC](https://discourse.vtk.org/t/vtk-9-1-python-overloaded-method-call-broken/8235/2 "2022-04-08T05:39:24Z")
The enumeration type isn’t being recognized as a valid argument for the vtkDICOMTag constructor anymore.
The generated code used to have these single-argument overloads for the vtkDICOMTag constructor:
```auto
static PyMethodDef PyvtkDICOMTag_vtkDICOMTag_Methods[] = {
{nullptr, PyvtkDICOMTag_vtkDICOMTag_s3, METH_VARARGS,
"@E DC.EnumType"},
{nullptr, PyvtkDICOMTag_vtkDICOMTag_s4, METH_VARARGS,
"@W vtkDICOMTag"},
{nullptr, nullptr, 0, nullptr}
};
```
But now it just has this:
```auto
static PyMethodDef PyvtkDICOMTag_vtkDICOMTag_Methods[] = {
{nullptr, PyvtkDICOMTag_vtkDICOMTag_s3, METH_VARARGS,
"@W vtkDICOMTag"},
{nullptr, nullptr, 0, nullptr}
};
```
The problem might have been introduced by [7903d3f1](https://gitlab.kitware.com/vtk/vtk/-/commit/f7903d3f1), but I haven’t confirmed yet.
---
### Author:  [@dgobbi](https://discourse.vtk.org/u/dgobbi)
#### Post date: [April 8, 2022, 1:59pm UTC](https://discourse.vtk.org/t/vtk-9-1-python-overloaded-method-call-broken/8235/3 "2022-04-08T13:59:43Z")
I can fix the issue by removing the “`; WRAPEXCLUDE`” from the entry in `vtkDICOM-hierarchy.txt`:
```nohighlight
DC::EnumType : enum ; vtkDICOMDictHash.h ; vtkDICOM ; WRAPEXCLUDE
```
I’ll work on a patch for `vtkWrapHierarchy.c` to properly handle enum types in namespaces.
---
### Author:  [@efahl](https://discourse.vtk.org/u/efahl)
#### Post date: [April 8, 2022, 2:44pm UTC](https://discourse.vtk.org/t/vtk-9-1-python-overloaded-method-call-broken/8235/4 "2022-04-08T14:44:49Z")
Thanks, David. Absolutely no hurry on my part, I’ll just keep digging around and see if I can find anything else related.
---
### Author:  [@dgobbi](https://discourse.vtk.org/u/dgobbi)
#### Post date: [April 9, 2022, 3:35pm UTC](https://discourse.vtk.org/t/vtk-9-1-python-overloaded-method-call-broken/8235/5 "2022-04-09T15:35:36Z")
I’ve submitted a fix ([!9062](https://gitlab.kitware.com/vtk/vtk/-/merge_requests/9062/diffs)). Thanks for reporting the issue.
---
### Author:  [@efahl](https://discourse.vtk.org/u/efahl)
#### Post date: [April 9, 2022, 7:55pm UTC](https://discourse.vtk.org/t/vtk-9-1-python-overloaded-method-call-broken/8235/6 "2022-04-09T19:55:07Z")
I merged your fix, rebuilt and tested. All looks good, thanks!