Ensure proper Pybind11 is found. (#1961)

* Add pybind11 version to config.
* Add version check for PB11.
* Bump CMake a tiny bit.

.github/workflows/test-everything.yml

@@ -19,7 +19,7 @@ jobs:
             cc:    "gcc-8",
             cxx:   "g++-8",
             py:    "3.7",
-            cmake: "3.18.x",
+            cmake: "3.19.x",
             mpi:   "ON",
             simd:  "OFF"
           }
@@ -29,7 +29,7 @@ jobs:
             cc:    "clang-8",
             cxx:   "clang++-8",
             py:    "3.7",
-            cmake: "3.18.x",
+            cmake: "3.19.x",
             mpi:   "ON",
             simd:  "OFF"
           }
@@ -39,7 +39,7 @@ jobs:
             cc:    "clang",
             cxx:   "clang++",
             py:    "3.7",
-            cmake: "3.18.x",
+            cmake: "3.19.x",
             mpi:   "ON",
             simd:  "OFF"
           }

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.18)
+cmake_minimum_required(VERSION 3.19)
 include(CMakeDependentOption)
 
 # Make CUDA support throw errors if architectures remain unclear

doc/install/build_install.rst

@@ -605,6 +605,20 @@ on your target system that are not covered here, please make an issue on the
 Arbor `Github issues <https://github.com/arbor-sim/arbor/issues>`_ page.
 We will do our best to help you directly, and update this guide to help other users.
 
+.. warn::
+
+   On many HPC systems a tool called ``module`` or ``ml`` is installed, which
+   use the ``CPATH`` environment variable to set up include paths for building.
+   The contents of this variable are forced on all compilations and by extension
+   to dependency generation. This can lead to the wrong headers being picked up
+   despite ``CMake`` reporting the correct versions, which can produce spurious
+   errors.
+
+   If you are using one of these tools (and possibly ```easybuid``) and encounter
+   such problems, try to ``module unload`` as many modules as possibe. One example
+   has been found with JSC clusters and an outdated pybind11 which was brought in
+   by ``ml SciPy-Stack``.
+
 .. _install-mpi:
 
 MPI

python/CMakeLists.txt

@@ -16,7 +16,7 @@ if(ARB_USE_BUNDLED_PYBIND11)
   # instead of using find_package.
   add_subdirectory(${pb11_src_dir} pybind11)
 else()
-  find_package(pybind11 REQUIRED)
+  find_package(pybind11 2.8.1 REQUIRED)
 endif()
 
 set(pyarb_source

python/config.cpp

@@ -52,6 +52,16 @@ pybind11::dict config() {
     dict[pybind11::str("version")] = pybind11::str(ARB_VERSION);
     dict[pybind11::str("source")]  = pybind11::str(ARB_SOURCE_ID);
     dict[pybind11::str("arch")]    = pybind11::str(ARB_ARCH);
+    {
+#define mk_tok(x) #x
+#define mk_ver(M, m, p) mk_tok(M) "." mk_tok(m) "." mk_tok(p)
+        const char* version = mk_ver(PYBIND11_VERSION_MAJOR,
+                                     PYBIND11_VERSION_MINOR,
+                                     PYBIND11_VERSION_PATCH);
+        dict[pybind11::str("pybind-version")] = pybind11::str(version);
+#undef mk_ver
+#undef mk_tok
+    }
     return dict;
 }
 

python/pyarb.hpp

@@ -13,6 +13,18 @@
 
 #include <pybind11/pybind11.h>
 
+// Version check
+#define mk_tok(x) #x
+#define mk_ver(M, m, p) mk_tok(M) "." mk_tok(m) "." mk_tok(p)
+#define PB11_ERR(M, m, p) "Required version of pybind11 is 2.8.1 <= version < 3.0.0 Found " mk_ver(M, m, p)
+static_assert((PYBIND11_VERSION_HEX >= 0x02080100)
+              &&
+              (PYBIND11_VERSION_HEX  < 0x03000000),
+              PB11_ERR(PYBIND11_VERSION_MAJOR, PYBIND11_VERSION_MINOR, PYBIND11_VERSION_PATCH));
+#undef PB11_ERR
+#undef mk_ver
+#undef mk_tok
+
 namespace pyarb {
 
 // Sample recorder object interface.

spack/package.py

@@ -59,7 +59,7 @@ class Arbor(CMakePackage, CudaPackage):
     conflicts("%cce@:9.1")
     conflicts("%intel")
 
-    depends_on("cmake@3.12:", type="build")
+    depends_on("cmake@3.19:", type="build")
 
     # misc dependencies
     depends_on("fmt@7.1:", when="@0.5.3:")  # required by the modcc compiler