openPMD · franzpoeschel · Feb 18, 2026 · Apr 8, 2026 · Apr 8, 2026 · Feb 6, 2026
diff --git a/.appveyor.yml b/.appveyor.yml
@@ -3,7 +3,7 @@ environment:
     - TARGET_ARCH: x64
       CONDA_PY: 3.10
       CONDA_INSTALL_LOCN: C:\\Miniconda37-x64
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       platform: x64
       SHARED: OFF
 
@@ -101,12 +101,12 @@ before_build:
   # Compiler & Generator Selection
   - cmd: if "%APPVEYOR_BUILD_WORKER_IMAGE%"=="Visual Studio 2017" set OPENPMD_CMAKE_GENERATOR=Visual Studio 15 2017
   - cmd: if "%APPVEYOR_BUILD_WORKER_IMAGE%"=="Visual Studio 2019" set OPENPMD_CMAKE_GENERATOR=Visual Studio 16 2019
-  - cmd: if "%TARGET_ARCH%"=="x64" set OPENPMD_CMAKE_GENERATOR=%OPENPMD_CMAKE_GENERATOR% Win64
 #  - cmd: if "%TARGET_ARCH%"=="x86" "C:\Program Files (x86)\Microsoft Visual Studio 15.9\VC\vcvarsall.bat" x86
 #  - cmd: if "%TARGET_ARCH%"=="x64" "C:\Program Files (x86)\Microsoft Visual Studio 15.9\VC\vcvarsall.bat" amd64
 
   # CMake configure
-  - cmd: cmake -G "%OPENPMD_CMAKE_GENERATOR%" -DCMAKE_BUILD_TYPE=%CONFIGURATION% -DBUILD_SHARED_LIBS=%SHARED% -DBUILD_TESTING=ON -DopenPMD_USE_PYTHON=ON -DPython_EXECUTABLE="%CONDA_INSTALL_LOCN%\python.exe" -DCMAKE_INSTALL_PREFIX="%CONDA_INSTALL_LOCN%" -DCMAKE_INSTALL_BINDIR="Library\bin" ".."
+  - cmd: if "%TARGET_ARCH%"=="x64" cmake -G "%OPENPMD_CMAKE_GENERATOR%" -A "%TARGET_ARCH%" -DCMAKE_BUILD_TYPE=%CONFIGURATION% -DBUILD_SHARED_LIBS=%SHARED% -DBUILD_TESTING=ON -DopenPMD_USE_PYTHON=ON -DPython_EXECUTABLE="%CONDA_INSTALL_LOCN%\python.exe" -DCMAKE_INSTALL_PREFIX="%CONDA_INSTALL_LOCN%" -DCMAKE_INSTALL_BINDIR="Library\bin" ".."
+  - cmd: if "%TARGET_ARCH%"=="x86" cmake -G "%OPENPMD_CMAKE_GENERATOR%" -DCMAKE_BUILD_TYPE=%CONFIGURATION% -DBUILD_SHARED_LIBS=%SHARED% -DBUILD_TESTING=ON -DopenPMD_USE_PYTHON=ON -DPython_EXECUTABLE="%CONDA_INSTALL_LOCN%\python.exe" -DCMAKE_INSTALL_PREFIX="%CONDA_INSTALL_LOCN%" -DCMAKE_INSTALL_BINDIR="Library\bin" ".."
 
 build_script:
   - cmd: cmake --build . --config %CONFIGURATION% -j 2

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -1,7 +1,49 @@
 .. _install-changelog:
 
 Changelog
-=========
+==========
+
+0.17.1
+------
+**Date:** YYYY-MM-DD
+
+Bug Fixes
+"""""""""
+
+- ADIOS2:
+
+  - Flush dirty ADIOS2 files in sorted order (#1868)
+  - Keep written flag consistent across MPI ranks for rankTable (#1869)
+  - Fix parallel deletion (#1858)
+  - Do not flush if the backend does not support Span API (#1863)
+  - Enable stats by default, starting ADIOS2 v2.12.0 (#1877)
+- HDF5:
+
+  - Execute close operations also upon failure (#1866 #1870 #1872)
+- API:
+
+  - Cache Iteration indexes instead of computing them on the spot (#1860 #1873)
+  - Harmonize Datatype equality checks (#1854)
+  - create_directories: preserve sticky and setgid permissions (#1855)
+
+Other
+"""""
+
+- Python:
+
+  - Fix keep_alive specifications, add tests for keep_alive (#1851)
+  - Remove duplicate Python test (#1867)
+  - Reacquire GIL for deallocation operations (#1878)
+- Dependencies:
+
+  - Version bump toml11 to recent main branch (b32a2fff0d27e1f7522f26a125101500ddb47156), nlohmann_json to 3.12.0 (#1842 #1874)
+  - Version bump pybind11 -> 3.0.2 (#1849)
+- CI/Infrastructure:
+
+  - Fix AppVeyor 64bit build (#1832)
+- Tests:
+
+  - Migrate C++ tests to Catch2 v3 (#1823 #1875)
 
 0.17.0
 ------

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -525,6 +525,9 @@ if(openPMD_BUILD_TESTING)
     add_library(openPMD::thirdparty::Catch2 INTERFACE IMPORTED)
     target_link_libraries(openPMD::thirdparty::Catch2
             INTERFACE Catch2::Catch2)
+    add_library(openPMD::thirdparty::Catch2WithMain INTERFACE IMPORTED)
+    target_link_libraries(openPMD::thirdparty::Catch2WithMain
+            INTERFACE Catch2::Catch2WithMain)
 endif()
 
 if(openPMD_HAVE_MPI)
@@ -770,14 +773,11 @@ if(openPMD_HAVE_PYTHON)
 endif()
 
 if(openPMD_BUILD_TESTING)
-    # compile Catch2 implementation part separately
-    add_library(CatchRunner ${_openpmd_lib_type}
-        test/CatchRunner.cpp)  # Always MPI_Init with Serial Fallback
-    add_library(CatchMain   ${_openpmd_lib_type}
-        test/CatchMain.cpp)    # Serial only
+    # CatchRunner: custom main with MPI support for parallel tests
+    # In Catch2 v3, we link to Catch2 (not Catch2WithMain) since we provide our own main
+    add_library(CatchRunner ${_openpmd_lib_type} test/CatchRunner.cpp)
     openpmd_cxx_required(CatchRunner)
-    openpmd_cxx_required(CatchMain)
-    set_target_properties(CatchRunner CatchMain PROPERTIES
+    set_target_properties(CatchRunner PROPERTIES
         ARCHIVE_OUTPUT_DIRECTORY ${openPMD_ARCHIVE_OUTPUT_DIRECTORY}
         LIBRARY_OUTPUT_DIRECTORY ${openPMD_LIBRARY_OUTPUT_DIRECTORY}
         RUNTIME_OUTPUT_DIRECTORY ${openPMD_RUNTIME_OUTPUT_DIRECTORY}
@@ -788,7 +788,6 @@ if(openPMD_BUILD_TESTING)
         WINDOWS_EXPORT_ALL_SYMBOLS ON
     )
     set_target_properties(CatchRunner PROPERTIES COMPILE_PDB_NAME CatchRunner)
-    set_target_properties(CatchMain PROPERTIES COMPILE_PDB_NAME CatchMain)
     # note: same as above, but for Multi-Config generators
     if(isMultiConfig)
         foreach(CFG IN LISTS CMAKE_CONFIGURATION_TYPES)
@@ -801,20 +800,10 @@ if(openPMD_BUILD_TESTING)
                 PDB_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_PDB_OUTPUT_DIRECTORY}/${CFG}
                 COMPILE_PDB_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_COMPILE_PDB_OUTPUT_DIRECTORY}/${CFG}
             )
-            set_target_properties(CatchMain PROPERTIES
-                COMPILE_PDB_NAME_${CFG_UPPER} CatchMain
-                ARCHIVE_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_ARCHIVE_OUTPUT_DIRECTORY}/${CFG}
-                LIBRARY_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_LIBRARY_OUTPUT_DIRECTORY}/${CFG}
-                RUNTIME_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_RUNTIME_OUTPUT_DIRECTORY}/${CFG}
-                PDB_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_PDB_OUTPUT_DIRECTORY}/${CFG}
-                COMPILE_PDB_OUTPUT_DIRECTORY_${CFG_UPPER} ${openPMD_COMPILE_PDB_OUTPUT_DIRECTORY}/${CFG}
-            )
         endforeach()
     endif()
     target_compile_options(CatchRunner PUBLIC ${_msvc_options})
-    target_compile_options(CatchMain   PUBLIC ${_msvc_options})
     target_link_libraries(CatchRunner PUBLIC openPMD::thirdparty::Catch2)
-    target_link_libraries(CatchMain   PUBLIC openPMD::thirdparty::Catch2)
     if(openPMD_HAVE_MPI)
         target_link_libraries(CatchRunner PUBLIC ${openPMD_MPI_TARGETS})
         target_compile_definitions(CatchRunner PUBLIC openPMD_HAVE_MPI=1)
@@ -837,6 +826,7 @@ if(openPMD_BUILD_TESTING)
         elseif(${test_name} STREQUAL "Core")
             list(APPEND ${out_list}
                 test/Files_Core/automatic_variable_encoding.cpp
+                test/Files_Core/read_nonexistent_attribute.cpp
             )
         endif()
     endmacro()
@@ -875,9 +865,11 @@ if(openPMD_BUILD_TESTING)
         endif()
         target_link_libraries(${testname}Tests PRIVATE openPMD)
         if(${testname} MATCHES "Parallel.+$")
+            # Parallel tests use CatchRunner (custom main with MPI)
             target_link_libraries(${testname}Tests PRIVATE CatchRunner)
         else()
-            target_link_libraries(${testname}Tests PRIVATE CatchMain)
+            # Serial tests use Catch2WithMain (provides default main)
+            target_link_libraries(${testname}Tests PRIVATE openPMD::thirdparty::Catch2WithMain)
         endif()
 
         if(${testname} STREQUAL JSON)

diff --git a/cmake/dependencies/catch.cmake b/cmake/dependencies/catch.cmake
@@ -1,3 +1,22 @@
+function(catch_preconfigure)
+    set(_old_BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS})
+    set(BUILD_SHARED_LIBS OFF CACHE BOOL "" FORCE)
+endfunction()
+
+function(catch_postconfigure)
+    set(BUILD_SHARED_LIBS ${_old_BUILD_SHARED_LIBS})
+    unset(_old_BUILD_SHARED_LIBS)
+    # Mark Catch2 as system code to suppress warnings and set position independent code
+    # Ensure Catch2 is built with PIC so it can be linked into shared libraries
+    set_target_properties(Catch2 PROPERTIES
+        POSITION_INDEPENDENT_CODE ON
+        INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "$<TARGET_PROPERTY:Catch2,INTERFACE_INCLUDE_DIRECTORIES>"
+    )
+    if(CMAKE_CXX_CLANG_TIDY)
+        set_target_properties(Catch2 PROPERTIES CXX_CLANG_TIDY "")
+    endif()
+endfunction()
+
 function(find_catch2)
     if(TARGET Catch2::Catch2)
         message(STATUS "Catch2::Catch2 target already imported")
@@ -19,8 +38,11 @@ function(find_catch2)
     if(TARGET Catch2::Catch2)
         # nothing to do, target already exists in the superbuild
     elseif(openPMD_USE_INTERNAL_CATCH AND openPMD_catch_src)
+        catch_preconfigure()
         add_subdirectory(${openPMD_catch_src} _deps/localCatch2-build/)
+        catch_postconfigure()
     elseif(openPMD_USE_INTERNAL_CATCH AND (openPMD_catch_tar OR openPMD_catch_branch))
+        catch_preconfigure()
         include(FetchContent)
         if(openPMD_catch_tar)
             FetchContent_Declare(fetchedCatch2
@@ -36,7 +58,7 @@ function(find_catch2)
             )
         endif()
         FetchContent_MakeAvailable(fetchedCatch2)
-
+        catch_postconfigure()
         # advanced fetch options
         mark_as_advanced(FETCHCONTENT_BASE_DIR)
         mark_as_advanced(FETCHCONTENT_FULLY_DISCONNECTED)
@@ -45,7 +67,7 @@ function(find_catch2)
         mark_as_advanced(FETCHCONTENT_UPDATES_DISCONNECTED)
         #mark_as_advanced(FETCHCONTENT_UPDATES_DISCONNECTED_FETCHEDCatch2)
     elseif(NOT openPMD_USE_INTERNAL_CATCH)
-        find_package(Catch2 2.13.10 CONFIG REQUIRED)
+        find_package(Catch2 3.0.0 CONFIG REQUIRED)
         message(STATUS "Catch2: Found version '${Catch2_VERSION}'")
     endif()
 endfunction()
@@ -56,18 +78,18 @@ set(openPMD_catch_src ""
     "Local path to Catch2 source directory (preferred if set)")
 
 # tarball fetcher
-set(openPMD_catch_tar "https://github.com/catchorg/Catch2/archive/refs/tags/v2.13.10.tar.gz"
+set(openPMD_catch_tar "https://github.com/catchorg/Catch2/archive/refs/tags/v3.11.0.tar.gz"
     CACHE STRING
     "Remote tarball link to pull and build Catch2 from if(openPMD_USE_INTERNAL_CATCH)")
-set(openPMD_catch_tar_hash "SHA256=d54a712b7b1d7708bc7a819a8e6e47b2fde9536f487b89ccbca295072a7d9943"
+set(openPMD_catch_tar_hash "SHA256=82fa1cb59dc28bab220935923f7469b997b259eb192fb9355db62da03c2a3137"
     CACHE STRING
     "Hash checksum of the tarball of Catch2 if(openPMD_USE_INTERNAL_CATCH)")
 
 # Git fetcher
 set(openPMD_catch_repo "https://github.com/catchorg/Catch2.git"
     CACHE STRING
     "Repository URI to pull and build Catch2 from if(openPMD_USE_INTERNAL_CATCH)")
-set(openPMD_catch_branch "v2.13.10"
+set(openPMD_catch_branch "v3.11.0"
     CACHE STRING
     "Repository branch for openPMD_catch_repo if(openPMD_USE_INTERNAL_CATCH)")
 

diff --git a/cmake/dependencies/json.cmake b/cmake/dependencies/json.cmake
@@ -56,18 +56,18 @@ set(openPMD_json_src ""
     "Local path to nlohmann_json source directory (preferred if set)")
 
 # tarball fetcher
-set(openPMD_json_tar "https://github.com/nlohmann/json/archive/refs/tags/v3.11.3.tar.gz"
+set(openPMD_json_tar "https://github.com/nlohmann/json/archive/refs/tags/v3.12.0.tar.gz"
     CACHE STRING
     "Remote tarball link to pull and build nlohmann_json from if(openPMD_USE_INTERNAL_JSON)")
-set(openPMD_json_tar_hash "SHA256=0d8ef5af7f9794e3263480193c491549b2ba6cc74bb018906202ada498a79406"
+set(openPMD_json_tar_hash "SHA256=4b92eb0c06d10683f7447ce9406cb97cd4b453be18d7279320f7b2f025c10187"
     CACHE STRING
     "Hash checksum of the tarball of nlohmann_json if(openPMD_USE_INTERNAL_JSON)")
 
 # Git fetcher
 set(openPMD_json_repo "https://github.com/nlohmann/json.git"
     CACHE STRING
     "Repository URI to pull and build nlohmann_json from if(openPMD_USE_INTERNAL_JSON)")
-set(openPMD_json_branch "v3.11.3"
+set(openPMD_json_branch "v3.12.0"
     CACHE STRING
     "Repository branch for openPMD_json_repo if(openPMD_USE_INTERNAL_JSON)")
 

diff --git a/cmake/dependencies/pybind11.cmake b/cmake/dependencies/pybind11.cmake
@@ -51,9 +51,9 @@ function(find_pybind11)
         mark_as_advanced(FETCHCONTENT_UPDATES_DISCONNECTED_FETCHEDpybind11)
     elseif(NOT openPMD_USE_INTERNAL_PYBIND11)
         if(openPMD_USE_PYTHON STREQUAL AUTO)
-            find_package(pybind11 2.13.0 CONFIG)
+            find_package(pybind11 3.0.0 CONFIG)
         elseif(openPMD_USE_PYTHON)
-            find_package(pybind11 2.13.0 CONFIG REQUIRED)
+            find_package(pybind11 3.0.0 CONFIG REQUIRED)
         endif()
         if(TARGET pybind11::module)
             message(STATUS "pybind11: Found version '${pybind11_VERSION}'")
@@ -67,18 +67,18 @@ set(openPMD_pybind11_src ""
     "Local path to pybind11 source directory (preferred if set)")
 
 # tarball fetcher
-set(openPMD_pybind11_tar "https://github.com/pybind/pybind11/archive/refs/tags/v2.13.6.tar.gz"
+set(openPMD_pybind11_tar "https://github.com/pybind/pybind11/archive/refs/tags/v3.0.2.tar.gz"
         CACHE STRING
         "Remote tarball link to pull and build pybind11 from if(openPMD_USE_INTERNAL_PYBIND11)")
-set(openPMD_pybind11_tar_hash "SHA256=e08cb87f4773da97fa7b5f035de8763abc656d87d5773e62f6da0587d1f0ec20"
+set(openPMD_pybind11_tar_hash "SHA256=2f20a0af0b921815e0e169ea7fec63909869323581b89d7de1553468553f6a2d"
         CACHE STRING
         "Hash checksum of the tarball of pybind11 if(openPMD_USE_INTERNAL_PYBIND11)")
 
 # Git fetcher
 set(openPMD_pybind11_repo "https://github.com/pybind/pybind11.git"
     CACHE STRING
     "Repository URI to pull and build pybind11 from if(openPMD_USE_INTERNAL_PYBIND11)")
-set(openPMD_pybind11_branch "v2.13.6"
+set(openPMD_pybind11_branch "v3.0.2"
     CACHE STRING
     "Repository branch for openPMD_pybind11_repo if(openPMD_USE_INTERNAL_PYBIND11)")
 

diff --git a/cmake/dependencies/toml11.cmake b/cmake/dependencies/toml11.cmake
@@ -64,18 +64,18 @@ set(openPMD_toml11_src ""
     "Local path to toml11 source directory (preferred if set)")
 
 # tarball fetcher
-set(openPMD_toml11_tar "https://github.com/ToruNiina/toml11/archive/refs/tags/v4.2.0.tar.gz"
+set(openPMD_toml11_tar "https://github.com/ToruNiina/toml11/archive/b32a2fff0d27e1f7522f26a125101500ddb47156.tar.gz"
         CACHE STRING
         "Remote tarball link to pull and build toml11 from if(openPMD_USE_INTERNAL_TOML11)")
-set(openPMD_toml11_tar_hash "SHA256=9287971cd4a1a3992ef37e7b95a3972d1ae56410e7f8e3f300727ab1d6c79c2c"
+set(openPMD_toml11_tar_hash "SHA256=c82df2d6a437795a1b5ac0b87886d5eb481deb60d6e79adb1688017857347cda"
         CACHE STRING
         "Hash checksum of the tarball of toml11 if(openPMD_USE_INTERNAL_TOML11)")
 
 # Git fetcher
 set(openPMD_toml11_repo "https://github.com/ToruNiina/toml11.git"
     CACHE STRING
     "Repository URI to pull and build toml11 from if(openPMD_USE_INTERNAL_TOML11)")
-set(openPMD_toml11_branch "v3.7.1"
+set(openPMD_toml11_branch "b32a2fff0d27e1f7522f26a125101500ddb47156"
     CACHE STRING
     "Repository branch for openPMD_toml11_repo if(openPMD_USE_INTERNAL_TOML11)")
 

diff --git a/docs/source/backends/adios2.rst b/docs/source/backends/adios2.rst
@@ -84,7 +84,7 @@ environment variable                    default    description
 ``OPENPMD_ADIOS2_ENGINE``               ``File``   `ADIOS2 engine <https://adios2.readthedocs.io/en/latest/engines/engines.html>`_
 ``OPENPMD_ADIOS2_PRETEND_ENGINE``       *empty*    Pretend that an (unknown) ADIOS2 engine is in fact another one (also see the ``adios2.pretend_engine`` :ref:`parameter <backendconfig-adios2>`).
 ``OPENPMD2_ADIOS2_USE_GROUP_TABLE``     ``0``      Use group table (see below)
-``OPENPMD_ADIOS2_STATS_LEVEL``          ``0``      whether to generate statistics for variables in ADIOS2. (``1``: yes, ``0``: no).
+``OPENPMD_ADIOS2_STATS_LEVEL``          see below  Whether to generate statistics for variables in ADIOS2. (``1``: yes, ``0``: no)
 ``OPENPMD_ADIOS2_ASYNC_WRITE``          ``0``      ADIOS2 BP5 engine: 1 means setting "AsyncWrite" in ADIOS2 to "on". Flushes will go to the buffer by default (see ``preferred_flush_target``).
 ``OPENPMD_ADIOS2_BP5_BufferChunkMB``    ``0``      ADIOS2 BP5 engine: applies when using either EveryoneWrites or EveryoneWritesSerial aggregation
 ``OPENPMD_ADIOS2_BP5_MaxShmMB``         ``0``      ADIOS2 BP5 engine: applies when using TwoLevelShm aggregation
@@ -98,7 +98,7 @@ Please refer to the `ADIOS2 documentation <https://adios2.readthedocs.io/en/late
 
 Notice that the ADIOS2 backend is alternatively configurable via :ref:`JSON parameters <backendconfig>`.
 
-Due to performance considerations, the ADIOS2 backend configures ADIOS2 not to compute any dataset statistics (Min/Max) by default.
+Due to performance considerations, the ADIOS2 backend configures ADIOS2 not to compute any dataset statistics (Min/Max) by default for ADIOS2 versions up until v2.12.0. Starting with `v2.12.1 <https://github.com/ornladios/ADIOS2/releases/tag/v2.12.1>`_, the performance of statistics computation has been improved, so it is turned on by default.
 Statistics may be activated by setting the :ref:`JSON parameter <backendconfig>` ``adios2.engine.parameters.StatsLevel = "1"``.
 
 The ADIOS2 backend overrides the default unlimited queueing behavior of the SST engine with a more cautious limit of 2 steps that may be held in the queue at one time.