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vtk-9.2.6-36 and expat-2.7.1-1 seem to be incompatible when reading XML files with a field AppendedData. The problem seems to be identified (https://gitlab.kitware.com/vtk/vtk/-/commit/db8f9efca220c9d16a30958e179abae3379d0011) and a commit has been committed to the git repository for more than one year. Unfortunately, there is no released version containing that patch since then ! In consequence, all software that attempt to read such XML files are broken. Notable exceptions are paraview and the python-vtk module which seem to bundle their own versions of vtk... I have tried older versions of libexpat with LD_LIBRARY_PATH but libexpat.so.1.10.0 has the same failure and libexpat.so.1.9.0 has symbol issues (as it can have been expected). Thus there seems to be no simple workaround to the problem besides patching either vtk (I'm currently re-building the vtk rpm with the above patch) or libexpat (which seems complicated to me). Reproducible: Always Steps to Reproduce: 1.Compile the small program given in attachment with the command g++ -O3 -I/usr/include/vtk -o vtp vtp.cxx -lvtksys -lvtkIOXML -lvtkCommonCore 2.Execute the program with the file provided in attachment ./vtp HeadNNa2.vtp 3. The python script (in attachment) shows the proper output (and indicates that the python uses a vtk/expat variant different from the installed libraries). Actual Results: 2025-06-07 11:59:29.033 ( 0.015s) [ 7BE90B40] vtkXMLParser.cxx:375 ERR| vtkXMLDataParser (0x23c43a70): Error parsing XML in stream at line 34, column 14, byte index 2433: not well-formed (invalid token) 2025-06-07 11:59:29.037 ( 0.015s) [ 7BE90B40] vtkXMLReader.cxx:521 ERR| vtkXMLPolyDataReader (0x23c3e520): Error parsing input file. ReadXMLInformation aborting. 2025-06-07 11:59:29.037 ( 0.016s) [ 7BE90B40] vtkExecutive.cxx:740 ERR| vtkCompositeDataPipeline (0x23c2cde0): Algorithm vtkXMLPolyDataReader (0x23c3e520) returned failure for request: vtkInformation (0x23c41580) Debug: Off Modified Time: 90 Reference Count: 1 Registered Events: (none) Request: REQUEST_INFORMATION ALGORITHM_AFTER_FORWARD: 1 FORWARD_DIRECTION: 0 0 0 Expected Results: 528 1062 Additional Information: Potentially all apps using vtk may be affected.
Created attachment 2093339 [details] Data file
Created attachment 2093340 [details] Source code showing the problem
Created attachment 2093341 [details] Python code showing the proper output and that the python module uses its own vtk libs
Just checked that the patch in vtk corrects the problem (by interposing a small shared library with the current git code for vtkXMLDataParser). Thus adding the patch in attachment to the vtk rpm build should solve the problem.
Created attachment 2093357 [details] Patch to use for the vtk spec
Looks like VTK 9.4 or above would have this issue solved.
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But the error is still present on Fedora 43, which remains with the same vtk version !!!
Hi Theodore, I've opened a PR here with the patch included. It built fine on my local machine, but we'll wait for CI to run it on all targets. We should then be able to push it as an update for F43 too. Sorry for the delay. In the long run, it's probably better to upgrade to F44, since older releases do not get new major package updates in Fedora, as per the updates policy: I've bumped the release here to prevent the bug from being automatically closed again. Cheers,
Forgot the link to the policy: https://docs.fedoraproject.org/en-US/fesco/Updates_Policy/#stable-releases
(In reply to Ankur Sinha (FranciscoD) from comment #11) > Hi Theodore, > > I've opened a PR here with the patch included. It built fine on my local > machine, but we'll wait for CI to run it on all targets. We should then be > able to push it as an update for F43 too. > > Sorry for the delay. In the long run, it's probably better to upgrade to > F44, since older releases do not get new major package updates in Fedora, as > per the updates policy: Thank you very much. For the upgrade I agree, but I'm not totally free to make the step (normally, we are allowed to switch a little after the release). Yet, the bug remains for all the users of F43 (and F42 before) and that was why I reported it. For OpenMEEG (which is where I detected the bug), I made a interposition library to workaround the problem, so I'm no longer exposed to it for my own use (and that of OpenMEEG users). Thank you again.
FEDORA-2026-4036ef95fe (vtk-9.2.6-45.fc43) has been submitted as an update to Fedora 43. https://bodhi.fedoraproject.org/updates/FEDORA-2026-4036ef95fe
FEDORA-2026-4036ef95fe has been pushed to the Fedora 43 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-4036ef95fe` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-4036ef95fe See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2026-4036ef95fe (vtk-9.2.6-45.fc43) has been pushed to the Fedora 43 stable repository. If problem still persists, please make note of it in this bug report.