Check for match between shared lib and Python module

When the Python module is linked to the Cantera shared library,
it is possible that a user has multiple incompatible versions of
the library installed. This checks that the Cantera version and
Git commit are the same when importing the Python module, to avoid
crashes or erroneous behavior due to ABI mismatches.

include/cantera/base/global.h

@@ -102,6 +102,11 @@ void appdelete();
 //! @copydoc Application::thread_complete
 void thread_complete();
 
+//! Returns the Cantera version. This function when needing to access the version from a
+//! library, rather than the `CANTERA_VERSION` macro that is available at compile time.
+//! @since New in Cantera 3.0
+string version();
+
 //! Returns the hash of the git commit from which Cantera was compiled, if known
 std::string gitCommit();
 

include/cantera/cython/utils_utils.h

@@ -25,12 +25,23 @@ static std::map<std::string, PyObject*> mapped_PyWarnings = {
     {"User", PyExc_UserWarning}
 };
 
-// Wrappers for preprocessor defines
-inline std::string get_cantera_version()
+// Cantera version for Python module compilation
+inline std::string get_cantera_version_py()
+{
+    return CANTERA_VERSION;
+}
+
+// Git commit for Python module compilation
+inline std::string get_cantera_git_commit_py()
 {
-    return std::string(CANTERA_VERSION);
+#ifdef GIT_COMMIT
+    return GIT_COMMIT;
+#else
+    return "unknown";
+#endif
 }
 
+// Wrappers for preprocessor defines
 inline int get_sundials_version()
 {
     return CT_SUNDIALS_VERSION;

interfaces/cython/SConscript

@@ -33,14 +33,21 @@ if env["coverage"]:
 # Build the Python module
 cython_obj = []
 for pyxfile in multi_glob(localenv, "cantera", "pyx"):
-    cythonized = localenv.Command(
+    if pyxfile.name == "_utils.pyx":
+        # Define GIT_COMMIT only in _utils.pyx to avoid unnecessary recompilations
+        cython_env = localenv.Clone()
+        cython_env.Append(CPPDEFINES={'GIT_COMMIT': '\\"{0}\\"'.format(env['git_commit'])})
+    else:
+        cython_env = localenv
+
+    cythonized = cython_env.Command(
          f"cantera/{pyxfile.name.replace('.pyx', '.cpp')}", pyxfile,
          f'''${{python_cmd}} -c "import Cython.Build; Cython.Build.cythonize(r'${{SOURCE}}', compiler_directives={directives!r})"'''
     )
-    for pxd in multi_glob(localenv, "cantera", "pxd"):
-        localenv.Depends(cythonized, pxd)
+    for pxd in multi_glob(cython_env, "cantera", "pxd"):
+        cython_env.Depends(cythonized, pxd)
 
-    obj = localenv.SharedObject(
+    obj = cython_env.SharedObject(
         f"#build/temp-py/{pyxfile.name.split('.')[0]}", cythonized)
     cython_obj.append(obj)
 cython_obj.extend(env['python_ext_objects'])

interfaces/cython/cantera/_cantera.pyx

@@ -30,8 +30,8 @@ def bootstrap_cython_submodules():
 bootstrap_cython_submodules()
 
 # Import the contents of the individual .pyx files
-from ._onedim import *
 from ._utils import *
+from ._onedim import *
 from .solutionbase import *
 from .delegator import *
 from .func1 import *

interfaces/cython/cantera/_utils.pxd

@@ -72,12 +72,14 @@ cdef extern from "cantera/base/global.h" namespace "Cantera":
     cdef void Cxx_suppress_thermo_warnings "Cantera::suppress_thermo_warnings" (cbool)
     cdef void Cxx_use_legacy_rate_constants "Cantera::use_legacy_rate_constants" (cbool)
     cdef string CxxGitCommit "Cantera::gitCommit" ()
+    cdef string CxxVersion "Cantera::version" ()
     cdef cbool CxxUsesHDF5 "Cantera::usesHDF5" ()
     cdef cbool CxxDebugModeEnabled "Cantera::debugModeEnabled" ()
 
 
 cdef extern from "cantera/cython/utils_utils.h":
-    cdef string get_cantera_version()
+    cdef string get_cantera_version_py()
+    cdef string get_cantera_git_commit_py()
     cdef int get_sundials_version()
     cdef cppclass CxxPythonLogger "PythonLogger":
         pass

interfaces/cython/cantera/_utils.pyx

@@ -49,10 +49,20 @@ def get_data_directories():
 
 __sundials_version__ = '.'.join(str(get_sundials_version()))
 
-__version__ = pystr(get_cantera_version())
+__version__ = pystr(CxxVersion())
+
+if __version__ != pystr(get_cantera_version_py()):
+    raise ImportError("Mismatch betweeen Cantera Python module version "
+        f"({pystr(get_cantera_version_py())}) and Cantera shared library "
+        f"version ({__version__})")
 
 __git_commit__ = pystr(CxxGitCommit())
 
+if __git_commit__ != pystr(get_cantera_git_commit_py()):
+    raise ImportError("Mismatch betweeen Cantera Python module Git commit "
+        f"({pystr(get_cantera_git_commit_py())}) and Cantera shared library "
+        f"git commit ({__git_commit__})")
+
 _USE_SPARSE = False
 
 def debug_mode_enabled():

src/base/global.cpp

@@ -122,6 +122,11 @@ void thread_complete()
     app()->thread_complete();
 }
 
+string version()
+{
+    return CANTERA_VERSION;
+}
+
 std::string gitCommit()
 {
 #ifdef GIT_COMMIT