#1145664 cmake fails to find the hdf5 MPI build (HDF5_IS_PARALLEL)

Package:
libhdf5-mpi-dev
Source:
libhdf5-mpi-dev
Description:
HDF5 - development files - default MPI version
Submitter:
Drew Parsons
Date:
2026-08-26 13:21:02 UTC
Severity:
normal
#1145664#5
Date:
2026-08-26 13:19:58 UTC
From:
To:
cmake is failing to detect the MPI build of hdf5
searching via
find_dependency(HDF5 COMPONENTS C)

with libhdf5-dev and libhdf5-mpi-dev install
(and libhdf5-openmpi-dev)

e.g. debci tests of dolfinx-performance tests fail with
-- HDF5_DIR: /usr/lib/x86_64-linux-gnu/cmake/hdf5_serial
-- HDF5_DEFINITIONS: 
-- HDF5_INCLUDE_DIRS: /usr/include/hdf5/serial
...
CMake Error at /usr/lib/x86_64-linux-gnu/cmake/dolfinx/DOLFINXConfig.cmake:105 (message):
  Found serial HDF5 build, MPI HDF5 build required

I note that /usr/lib/x86_64-linux-gnu/cmake/hdf5 now appears to refer
to the MPI build (it includes set(${HDF5_PACKAGE_NAME}_PROVIDES_PARALLEL        ON)
but apparently cmake is finding
/usr/lib/x86_64-linux-gnu/cmake/hdf5_serial/ instead

Previously the MPI build was found by default if installed.
Something in hdf5 2.2.0 has changed (broken) the status quo.