ARROW-83 Version Check Warning is Obscured (#70)

Author: blink1073

bindings/python/docs/source/developer/installation.rst

@@ -50,6 +50,9 @@ Conda users can install ``libbson`` as follows::
 
   $ conda install --channel conda-forge libbson pkg-config
 
+The minimum required version is listed in ``pymongoarrow/version.py``.
+If you try to build with a lower version a ``ValueError`` will be raised.
+
 Build
 -----
 

bindings/python/pymongoarrow/__init__.py

@@ -29,11 +29,13 @@ def _parse_version(version):
 
 try:
     from pymongoarrow.lib import libbson_version
+except ImportError:
+    warnings.warn("This library has not been compiled")
+    libbson_version = None
 
+if libbson_version is not None:
     if _parse_version(libbson_version) < _parse_version(_MIN_LIBBSON_VERSION):
         raise ImportError(
             f"Expected libbson version {_MIN_LIBBSON_VERSION} or greater, "
             f"found {libbson_version}"
         )
-except ImportError:
-    warnings.warn("This library has not been compiled")

bindings/python/setup.py

@@ -33,6 +33,15 @@ def query_pkgconfig(cmd):
     return output
 
 
+def get_min_libbson_version():
+    version_ns = {}
+    here = os.path.dirname(__file__)
+    version_py = os.path.join(here, "pymongoarrow", "version.py")
+    with open(version_py) as f:
+        exec(compile(f.read(), version_py, "exec"), version_ns)
+    return version_ns["_MIN_LIBBSON_VERSION"]
+
+
 def append_libbson_flags(module):
     pc_path = "libbson-1.0"
     install_dir = os.environ.get("LIBBSON_INSTALL_DIR")
@@ -84,10 +93,21 @@ def append_libbson_flags(module):
         # We have added the library file without raising an error, so return.
         return
 
+    # Check for the existence of the library.
     lnames = query_pkgconfig("pkg-config --libs-only-l {}".format(pc_path))
     if not lnames:
         raise ValueError(f'Could not find "{pc_path}" library')
 
+    # Check against the minimum required version.
+    min_version = get_min_libbson_version()
+    mod_version = query_pkgconfig("pkg-config --modversion {}".format(pc_path))
+
+    if mod_version < min_version:
+        raise ValueError(
+            f"Cannot use {pc_path} with version {mod_version}, minimum required version is {min_version}"
+        )
+
+    # Gather the appropriate flags.
     cflags = query_pkgconfig("pkg-config --cflags {}".format(pc_path))
 
     if cflags: