openPMD · ax3l · Nov 8, 2019 · Nov 7, 2019
diff --git a/.travis.yml b/.travis.yml
@@ -18,7 +18,6 @@ env:
     - PATH: $PATH:$HOME/.cache/spack/bin
     - BUILD_TYPE: "Debug"
     - PYBIND11_VERSION=@2.3.0
-    - USE_JSON: ON
     - USE_SHARED: ON
 
 addons:
@@ -112,7 +111,6 @@ jobs:
     #         -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
     #         -DCMAKE_BUILD_TYPE=${BUILD_TYPE}
     #         -DopenPMD_USE_MPI=$USE_MPI
-    #         -DopenPMD_USE_JSON=$USE_JSON
     #         -DopenPMD_USE_HDF5=$USE_HDF5
     #         -DopenPMD_USE_ADIOS1=$USE_ADIOS1
     #         -DopenPMD_USE_ADIOS2=$USE_ADIOS2
@@ -128,7 +126,7 @@ jobs:
     #         exit 1;
     #       fi
     # - <<: *static_code_cpp
-      name: clang-tidy@5.0.0 +MPI -PY +H5 +JSON +ADIOS1 +ADIOS2
+      name: clang-tidy@5.0.0 +MPI -PY +H5 +ADIOS1 +ADIOS2
       sudo: false
       env:
         - CXXSPEC="%clang@5.0.0" USE_MPI=ON USE_PYTHON=OFF USE_HDF5=ON USE_ADIOS1=ON USE_ADIOS2=ON
@@ -151,7 +149,6 @@ jobs:
             -DCMAKE_CXX_CLANG_TIDY="$(which clang-tidy-5.0);-system-headers=0"
             -DCMAKE_BUILD_TYPE=Release
             -DopenPMD_USE_MPI=$USE_MPI
-            -DopenPMD_USE_JSON=$USE_JSON
             -DopenPMD_USE_HDF5=$USE_HDF5
             -DopenPMD_USE_ADIOS1=$USE_ADIOS1
             -DopenPMD_USE_ADIOS2=$USE_ADIOS2
@@ -189,7 +186,7 @@ jobs:
     # Clang 5.0.0
     - &test-cpp-unit
       stage: 'C++ Unit Tests'
-      name: clang@5.0.0 -MPI -PY +H5 +JSON -ADIOS1 -ADIOS2
+      name: clang@5.0.0 -MPI -PY +H5 -ADIOS1 -ADIOS2
       language: cpp
       dist: xenial
       env:
@@ -226,7 +223,6 @@ jobs:
           cmake
             -DCMAKE_BUILD_TYPE=${BUILD_TYPE}
             -DopenPMD_USE_MPI=$USE_MPI
-            -DopenPMD_USE_JSON=$USE_JSON
             -DopenPMD_USE_HDF5=$USE_HDF5
             -DopenPMD_USE_ADIOS1=$USE_ADIOS1
             -DopenPMD_USE_ADIOS2=$USE_ADIOS2
@@ -254,7 +250,7 @@ jobs:
         # - dpkg -i openPMD*.deb
         - ls -R $HOME/openPMD-test-install | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/   /' -e 's/-/|/'
     - <<: *test-cpp-unit
-      name: clang@5.0.0 +MPI -PY +H5 +JSON +ADIOS1 +ADIOS2
+      name: clang@5.0.0 +MPI -PY +H5 +ADIOS1 +ADIOS2
       language: python
       python: "3.6"
       env:
@@ -272,7 +268,7 @@ jobs:
         - CXX=clang++-5.0 && CC=clang-5.0
     # Clang 6.0.0 + Python 3.6.3 @ Xenial
     - <<: *test-cpp-unit
-      name: clang@6.0.0 -MPI +PY@3.6 +H5 +JSON +ADIOS1 +ADIOS2 libc++
+      name: clang@6.0.0 -MPI +PY@3.6 +H5 +ADIOS1 +ADIOS2 libc++
       language: python
       python: "3.6"
       env:
@@ -292,7 +288,7 @@ jobs:
         - CXX=clang++-6.0 && CC=clang-6.0 && CXXFLAGS="${CXXFLAGS} -stdlib=libc++ -I/usr/include/libcxxabi/"
     # Clang 7.0.0 + Python 3.8.0 @ Xenial
     - <<: *test-cpp-unit
-      name: clang@7.0.0 +MPI +PY@3.8 +H5 +JSON +ADIOS1 +ADIOS2 +Release
+      name: clang@7.0.0 +MPI +PY@3.8 +H5 +ADIOS1 +ADIOS2 +Release
       dist: xenial
       language: python
       python: "3.8"
@@ -311,12 +307,12 @@ jobs:
         - CXX=clang++ && CC=clang
     # Clang 7.0.0 + Python 3.7.1 + Address Sanitizer + Undefined Behavior Sanitizer @ Xenial
     - <<: *test-cpp-unit
-      name: clang@7.0.0 +MPI +PY@3.7 +H5 +JSON -ADIOS1 +ADIOS2 +ASan +UBSan +STATIC
+      name: clang@7.0.0 +MPI +PY@3.7 +H5 -ADIOS1 +ADIOS2 +ASan +UBSan +STATIC
       dist: xenial
       language: python
       python: "3.7"
       env:
-        - CXXSPEC="%clang@7.0.0" USE_MPI=ON USE_PYTHON=ON USE_HDF5=ON USE_ADIOS1=OFF USE_ADIOS2=ON USE_SHARED=OFF USE_JSON=ON USE_SAMPLES=ON
+        - CXXSPEC="%clang@7.0.0" USE_MPI=ON USE_PYTHON=ON USE_HDF5=ON USE_ADIOS1=OFF USE_ADIOS2=ON USE_SHARED=OFF USE_SAMPLES=ON
         # sanitizer options: test as much as possible and suppress OpenMPI memory leaks
         - ASAN_OPTIONS=detect_stack_use_after_return=1:detect_leaks=1:check_initialization_order=true:strict_init_order=true:detect_stack_use_after_scope=1:fast_unwind_on_malloc=0
         - LSAN_OPTIONS=suppressions=${TRAVIS_BUILD_DIR}/.travis/sanitizer/clang/Leak.supp
@@ -334,7 +330,7 @@ jobs:
         # - find / -name libclang_rt*
     # Clang 9.1.0-apple + Python 3.7.2 @ OSX "highsierra"
     - <<: *test-cpp-unit
-      name: AppleClang@9.1.0 -MPI +PY@3.7 +H5 +JSON +ADIOS1 -ADIOS2
+      name: AppleClang@9.1.0 -MPI +PY@3.7 +H5 +ADIOS1 -ADIOS2
       os: osx
       osx_image: xcode9.4
       sudo: required
@@ -348,7 +344,7 @@ jobs:
         - perl --version
     # Clang 10.0.0-apple + Python 3.7.2 @ OSX "mojave" with libc++
     - <<: *test-cpp-unit
-      name: AppleClang@10.0.0 -MPI +PY@3.7 +H5 +JSON -ADIOS1 +ADIOS2 libc++
+      name: AppleClang@10.0.0 -MPI +PY@3.7 +H5 -ADIOS1 +ADIOS2 libc++
       os: osx
       osx_image: xcode10.1
       sudo: required
@@ -362,7 +358,7 @@ jobs:
         - perl --version
     # GCC 4.9.4
     - <<: *test-cpp-unit
-      name: gcc@4.9.4 -MPI -PY +H5 +JSON +ADIOS1 +ADIOS2
+      name: gcc@4.9.4 -MPI -PY +H5 +ADIOS1 +ADIOS2
       dist: trusty
       language: python
       python: "3.6"
@@ -381,7 +377,7 @@ jobs:
         - CXX=g++-4.9 && CC=gcc-4.9
       script: *script-cpp-unit
     - <<: *test-cpp-unit
-      name: gcc@4.9.4 +MPI -PY +H5 +JSON +ADIOS1 -ADIOS2
+      name: gcc@4.9.4 +MPI -PY +H5 +ADIOS1 -ADIOS2
       dist: trusty
       language: python
       python: "3.6"
@@ -399,12 +395,12 @@ jobs:
       script: *script-cpp-unit
     # GCC 7.4.0
     - <<: *test-cpp-unit
-      name: gcc@7.4.0 -MPI -PY +H5 -JSON +ADIOS1 +ADIOS2@2.4.0
+      name: gcc@7.4.0 -MPI -PY +H5 +ADIOS1 +ADIOS2@2.4.0
       dist: trusty
       language: python
       python: "3.6"
       env:
-        - CXXSPEC="%gcc@7.4.0" USE_MPI=OFF USE_PYTHON=OFF USE_JSON=OFF USE_HDF5=ON USE_ADIOS1=ON USE_ADIOS2=ON ADIOS2_VERSION=@2.4.0 USE_SAMPLES=ON
+        - CXXSPEC="%gcc@7.4.0" USE_MPI=OFF USE_PYTHON=OFF USE_HDF5=ON USE_ADIOS1=ON USE_ADIOS2=ON ADIOS2_VERSION=@2.4.0 USE_SAMPLES=ON
       compiler: gcc
       addons:
         apt:
@@ -418,7 +414,7 @@ jobs:
         - CXX=g++-7 && CC=gcc-7
       script: *script-cpp-unit
     - <<: *test-cpp-unit
-      name: gcc@7.4.0 +MPI -PY +H5 +JSON +ADIOS1 -ADIOS2
+      name: gcc@7.4.0 +MPI -PY +H5 +ADIOS1 -ADIOS2
       dist: trusty
       language: python
       python: "3.6"
@@ -436,7 +432,7 @@ jobs:
       script: *script-cpp-unit
     # GCC 6.5.0 + Python 3.5
     - <<: *test-cpp-unit
-      name: gcc@6.5.0 -MPI +PY@3.5 +H5 +JSON +ADIOS1@1.13.1 -ADIOS2
+      name: gcc@6.5.0 -MPI +PY@3.5 +H5 +ADIOS1@1.13.1 -ADIOS2
       dist: trusty
       language: python
       python: "3.5"
@@ -456,7 +452,7 @@ jobs:
       script: *script-cpp-unit
     # GCC 8.1.0 + Python 3.7
     - <<: *test-cpp-unit
-      name: gcc@8.1.0 -MPI +PY@3.7 +H5 +JSON +ADIOS1 -ADIOS2 +STATIC
+      name: gcc@8.1.0 -MPI +PY@3.7 +H5 +ADIOS1 -ADIOS2 +STATIC
       language: python
       python: "3.7"
       sudo: required
@@ -477,7 +473,7 @@ jobs:
       script: *script-cpp-unit
     # GCC 6.5.0 + Python 3.6
     - <<: *test-cpp-unit
-      name: gcc@6.5.0 -MPI +PY@3.6 +H5@1.8.13 +JSON -ADIOS1 -ADIOS2
+      name: gcc@6.5.0 -MPI +PY@3.6 +H5@1.8.13 -ADIOS1 -ADIOS2
       dist: trusty
       language: python
       python: "3.6"
@@ -493,7 +489,7 @@ jobs:
       script: *script-cpp-unit
     # GCC 4.8.5 + Python 3.5.5
     - <<: *test-cpp-unit
-      name: gcc@4.8.5 -MPI +PY@3.5 +H5 +JSON -ADIOS1 -ADIOS2
+      name: gcc@4.8.5 -MPI +PY@3.5 +H5 -ADIOS1 -ADIOS2
       dist: trusty
       language: python
       python: "3.5"
@@ -517,7 +513,7 @@ jobs:
     ###########################################################################
     - &code_coverage
       stage: 'Code Coverage'
-      name: gcc@7.4.0 +MPI +PY +H5 +JSON +ADIOS1 -ADIOS2 +coveralls
+      name: gcc@7.4.0 +MPI +PY +H5 +ADIOS1 -ADIOS2 +coveralls
       sudo: required
       language: python
       python: "3.6"
@@ -565,7 +561,6 @@ jobs:
           cmake
             -DCMAKE_BUILD_TYPE=${BUILD_TYPE}
             -DopenPMD_USE_MPI=$USE_MPI
-            -DopenPMD_USE_JSON=$USE_JSON
             -DopenPMD_USE_HDF5=$USE_HDF5
             -DopenPMD_USE_ADIOS1=$USE_ADIOS1
             -DopenPMD_USE_ADIOS2=$USE_ADIOS2

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -38,7 +38,10 @@ Bug Fixes
 Other
 """""
 
-- NLohmann-JSON: updated to 3.7.0+ #556
+- JSON:
+
+  - the backend is now always enabled #587
+  - NLohmann-JSON dependency updated to 3.7.0+ #556
 
 
 0.9.0-alpha

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -56,7 +56,6 @@ function(openpmd_option name description default)
 endfunction()
 
 openpmd_option(MPI            "Parallel, Multi-Node I/O for clusters"     AUTO)
-openpmd_option(JSON           "JSON backend (.json files)"                AUTO)
 openpmd_option(HDF5           "HDF5 backend (.h5 files)"                  AUTO)
 openpmd_option(ADIOS1         "ADIOS1 backend (.bp files)"                AUTO)
 openpmd_option(ADIOS2         "ADIOS2 backend (.bp files)"                AUTO)
@@ -112,43 +111,20 @@ else()
     set(openPMD_HAVE_MPI FALSE)
 endif()
 
-# external library: nlohmann-json (optional)
-if(openPMD_USE_JSON STREQUAL AUTO)
-    if(openPMD_USE_INTERNAL_JSON)
-        set(JSON_BuildTests OFF CACHE INTERNAL "")
-        set(JSON_Install OFF CACHE INTERNAL "")  # only used PRIVATE
-        add_subdirectory("${openPMD_SOURCE_DIR}/share/openPMD/thirdParty/json")
-        set(openPMD_HAVE_JSON TRUE)
-        message(STATUS "nlohmann-json: Using INTERNAL version 3.7.0")
-    else()
-        find_package(nlohmann_json 3.7.0 CONFIG)
-        if(nlohmann_json_FOUND)
-            set(openPMD_HAVE_JSON TRUE)
-            message(STATUS "nlohmann-json: Found version ${nlohmann_json_VERSION}")
-        else()
-            set(openPMD_HAVE_JSON FALSE)
-        endif()
-    endif()
-elseif(openPMD_USE_JSON)
-    if(openPMD_USE_INTERNAL_JSON)
-        set(JSON_BuildTests OFF CACHE INTERNAL "")
-        set(JSON_Install OFF CACHE INTERNAL "")  # only used PRIVATE
-        add_subdirectory("${openPMD_SOURCE_DIR}/share/openPMD/thirdParty/json")
-        set(openPMD_HAVE_JSON TRUE)
-        message(STATUS "nlohmann-json: Using INTERNAL version 3.7.0")
-    else()
-        find_package(nlohmann_json 3.7.0 CONFIG REQUIRED)
-        set(openPMD_HAVE_JSON TRUE)
-        message(STATUS "nlohmann-json: Found version ${nlohmann_json_VERSION}")
-    endif()
+# external library: nlohmann-json (required)
+if(openPMD_USE_INTERNAL_JSON)
+    set(JSON_BuildTests OFF CACHE INTERNAL "")
+    set(JSON_Install OFF CACHE INTERNAL "")  # only used PRIVATE
+    add_subdirectory("${openPMD_SOURCE_DIR}/share/openPMD/thirdParty/json")
+    message(STATUS "nlohmann-json: Using INTERNAL version 3.7.0")
 else()
-    set(openPMD_HAVE_JSON FALSE)
-endif()
-if(openPMD_HAVE_JSON)
-    add_library(openPMD::thirdparty::nlohmann_json INTERFACE IMPORTED)
-    target_link_libraries(openPMD::thirdparty::nlohmann_json
-        INTERFACE nlohmann_json::nlohmann_json)
+    find_package(nlohmann_json 3.7.0 CONFIG REQUIRED)
+    message(STATUS "nlohmann-json: Found version ${nlohmann_json_VERSION}")
 endif()
+add_library(openPMD::thirdparty::nlohmann_json INTERFACE IMPORTED)
+target_link_libraries(openPMD::thirdparty::nlohmann_json
+    INTERFACE nlohmann_json::nlohmann_json)
+
 
 # external library: HDF5 (optional)
 if(openPMD_USE_HDF5 STREQUAL AUTO)
@@ -415,12 +391,10 @@ if(openPMD_HAVE_MPI)
     target_link_libraries(openPMD PUBLIC MPI::MPI_C MPI::MPI_CXX)
 endif()
 
-# JSON Backend
-if(openPMD_HAVE_JSON)
-    #target_link_libraries(openPMD PRIVATE openPMD::thirdparty::nlohmann_json)
-    target_include_directories(openPMD SYSTEM PRIVATE
-        $<TARGET_PROPERTY:openPMD::thirdparty::nlohmann_json,INTERFACE_INCLUDE_DIRECTORIES>)
-endif()
+# JSON Backend and User-Facing Runtime Options
+#target_link_libraries(openPMD PRIVATE openPMD::thirdparty::nlohmann_json)
+target_include_directories(openPMD SYSTEM PRIVATE
+    $<TARGET_PROPERTY:openPMD::thirdparty::nlohmann_json,INTERFACE_INCLUDE_DIRECTORIES>)
 
 # HDF5 Backend
 if(openPMD_HAVE_HDF5)

diff --git a/NEWS.rst b/NEWS.rst
@@ -10,6 +10,8 @@ We added support for ADIOS2 in this release.
 As soon as the ADIOS2 backend is enabled it will take precedence for ``.bp`` files over a potentially also enabled ADIOS1 backend.
 In order to prefer the legacy ADIOS1 backend in such a situation, set an environment variable: ``export OPENPMD_BP_BACKEND="ADIOS1"``.
 
+The JSON backend is now always enabled.
+The CMake option ``-DopenPMD_USE_JSON`` has been removed (as it is always ``ON`` now).
 
 0.9.0-alpha
 -----------

diff --git a/README.md b/README.md
@@ -101,11 +101,11 @@ Shipped internally in `share/openPMD/thirdParty/`:
 * [pybind11](https://github.com/pybind/pybind11) 2.3.0+ ([new BSD](https://github.com/pybind/pybind11/blob/master/LICENSE))
 * [NLohmann-JSON](https://github.com/nlohmann/json) 3.7.0+ ([MIT](https://github.com/nlohmann/json/blob/develop/LICENSE.MIT))
 
-Optional I/O backends:
+I/O backends:
 * [JSON](https://en.wikipedia.org/wiki/JSON)
-* [HDF5](https://support.hdfgroup.org/HDF5) 1.8.13+
-* [ADIOS1](https://www.olcf.ornl.gov/center-projects/adios) 1.13.1+
-* [ADIOS2](https://github.com/ornladios/ADIOS2) 2.4.0+
+* [HDF5](https://support.hdfgroup.org/HDF5) 1.8.13+ (optional)
+* [ADIOS1](https://www.olcf.ornl.gov/center-projects/adios) 1.13.1+ (optional)
+* [ADIOS2](https://github.com/ornladios/ADIOS2) 2.4.0+ (optional)
 
 while those can be built either with or without:
 * MPI 2.1+, e.g. OpenMPI 1.6.5+ or MPICH2
@@ -132,7 +132,7 @@ Choose *one* of the install methods below to get started:
 [![Spack Status](https://img.shields.io/badge/method-recommended-brightgreen.svg)](https://spack.readthedocs.io/en/latest/package_list.html#openpmd-api)
 
 ```bash
-# optional:               +python +adios1 +adios2 -mpi
+# optional:               +python +adios1 +adios2 -hdf5 -mpi
 spack install openpmd-api
 spack load -r openpmd-api
 ```
@@ -209,7 +209,6 @@ CMake controls options with prefixed `-D`, e.g. `-DopenPMD_USE_MPI=OFF`:
 | CMake Option                 | Values           | Description                                                                  |
 |------------------------------|------------------|------------------------------------------------------------------------------|
 | `openPMD_USE_MPI`            | **AUTO**/ON/OFF  | Parallel, Multi-Node I/O for clusters                                        |
-| `openPMD_USE_JSON`           | **AUTO**/ON/OFF  | JSON backend (`.json` files)                                                 |
 | `openPMD_USE_HDF5`           | **AUTO**/ON/OFF  | HDF5 backend (`.h5` files)                                                   |
 | `openPMD_USE_ADIOS1`         | **AUTO**/ON/OFF  | ADIOS1 backend (`.bp` files up to version BP3)                               |
 | `openPMD_USE_ADIOS2`         | **AUTO**/ON/OFF  | ADIOS2 backend (`.bp` files in BP3, BP4 or higher)                           |
@@ -258,7 +257,7 @@ export CMAKE_PREFIX_PATH=$HOME/somepath:$CMAKE_PREFIX_PATH
 
 Use the following lines in your project's `CMakeLists.txt`:
 ```cmake
-# supports:                       COMPONENTS MPI NOMPI JSON HDF5 ADIOS1 ADIOS2
+# supports:                       COMPONENTS MPI NOMPI HDF5 ADIOS1 ADIOS2
 find_package(openPMD 0.9.0 CONFIG)
 
 if(openPMD_FOUND)

diff --git a/Singularity b/Singularity
@@ -42,7 +42,6 @@ Supported frontends are C++11 and Python3.
     cmake /opt/openpmd-api       \
         -DopenPMD_USE_MPI=OFF    \
         -DopenPMD_USE_HDF5=ON    \
-        -DopenPMD_USE_JSON=ON    \
         -DopenPMD_USE_ADIOS1=ON  \
         -DopenPMD_USE_ADIOS2=OFF \
         -DopenPMD_USE_PYTHON=ON  \
@@ -63,7 +62,6 @@ Supported frontends are C++11 and Python3.
 %labels
     openPMD_HAVE_MPI OFF
     openPMD_HAVE_HDF5 ON
-    openPMD_HAVE_JSON ON
     openPMD_HAVE_ADIOS1 ON
     openPMD_HAVE_ADIOS2 OFF
     openPMD_HAVE_PYTHON ON
diff --git a/docs/Doxyfile b/docs/Doxyfile
@@ -15,7 +15,6 @@ USE_MDFILE_AS_MAINPAGE = README.md
 
 # "enable" all frontends and backends
 PREDEFINED        = openPMD_HAVE_MPI=1 \
-                    openPMD_HAVE_JSON=1 \
                     openPMD_HAVE_HDF5=1 \
                     openPMD_HAVE_ADIOS1=1 \
                     openPMD_HAVE_ADIOS2=1 \

diff --git a/docs/source/backends/json.rst b/docs/source/backends/json.rst
@@ -4,10 +4,7 @@ JSON Backend
 ============
 
 openPMD supports writing to and reading from JSON files.
-For this, the installed copy of openPMD must have been built with support for the JSON backend.
-To build openPMD with support for JSON, use the CMake option ``-DopenPMD_USE_JSON=ON``.
-For further information, check out the :ref:`installation guide <install>`,
-:ref:`build dependencies <development-dependencies>` and the :ref:`build options <development-buildoptions>`.
+The JSON backend is always available.
 
 
 JSON File Format

diff --git a/docs/source/dev/buildoptions.rst b/docs/source/dev/buildoptions.rst
@@ -15,7 +15,6 @@ CMake controls options with prefixed ``-D``, e.g. ``-DopenPMD_USE_MPI=OFF``:
 CMake Option                   Values          Description
 ============================== =============== ========================================================================
 ``openPMD_USE_MPI``            **AUTO**/ON/OFF Parallel, Multi-Node I/O for clusters
-``openPMD_USE_JSON``           **AUTO**/ON/OFF JSON backend (``.json`` files)
 ``openPMD_USE_HDF5``           **AUTO**/ON/OFF HDF5 backend (``.h5`` files)
 ``openPMD_USE_ADIOS1``         **AUTO**/ON/OFF ADIOS1 backend (``.bp`` files up to version BP3)
 ``openPMD_USE_ADIOS2``         **AUTO**/ON/OFF ADIOS2 backend (``.bp`` files in BP3, BP4 or higher)