Made the C extension mandatory when CBOR2_BUILD_C_EXTENSION=1

docs/versionhistory.rst

@@ -9,6 +9,8 @@ This library adheres to `Semantic Versioning <http://semver.org/>`_.
 
 - Added the ``cbor2`` command line tool (for ``pipx run cbor2``)
 - Added support for native date encoding (bschoenmaeckers)
+- Made the C extension mandatory when the environment variable ``CBOR2_BUILD_C_EXTENSION`` is set
+  to ``1``.
 - Fixed ``SystemError`` in the C extension when decoding a ``Fractional`` with a bad
   number of arguments
 - Fixed ``SystemError`` in the C extension when the decoder object hook raises an
@@ -22,6 +24,10 @@ This library adheres to `Semantic Versioning <http://semver.org/>`_.
   ``CBORDecodeValueError``
 - Fixed ``TypeError`` or ``ZeroDivisionError`` from a failed decoding of ``Fraction`` not being
   wrapped as ``CBORDecodeValueError``
+- Fixed ``TypeError`` or ``ValueError`` from a failed decoding of ``UUID`` not being wrapped as
+  ``CBORDecodeValueError``
+- Fixed ``TypeError`` from a failed decoding of ``MIMEMessage`` not being wrapped as
+  ``CBORDecodeValueError``
 
 **5.5.1** (2023-11-02)
 

setup.py

@@ -30,8 +30,10 @@ def check_libc():
 cpython = platform.python_implementation() == "CPython"
 windows = sys.platform.startswith("win")
 use_c_ext = os.environ.get("CBOR2_BUILD_C_EXTENSION", None)
+optional = True
 if use_c_ext == "1":
     build_c_ext = True
+    optional = False
 elif use_c_ext == "0":
     build_c_ext = False
 else:
@@ -57,7 +59,7 @@ def check_libc():
             "source/tags.c",
             "source/halffloat.c",
         ],
-        # optional=True,
+        optional=optional,
     )
     kwargs = {"ext_modules": [_cbor2]}
 else: