Merge pull request #2079 from minrk/cpython-cffi

allow building cffi on cpython

Author: minrk

.github/workflows/test.yml

@@ -82,6 +82,10 @@ jobs:
           - os: ubuntu-24.04
             python: "3.12"
 
+          - os: ubuntu-24.04
+            python: "3.13"
+            backend: cffi
+
           - os: ubuntu-24.04
             python: "3.13"
 
@@ -193,6 +197,12 @@ jobs:
         run: |
           echo "ZMQ_PREFIX=${{ matrix.zmq }}" >> "$GITHUB_ENV"
 
+      - name: set $PYZMQ_BACKEND
+        if: matrix.backend
+        run: |
+          echo "PYZMQ_BACKEND=${{ matrix.backend }}" >> "$GITHUB_ENV"
+          pip install cffi
+
       - name: install libzmq-dev
         if: matrix.zmq == 'head'
         run: |

CMakeLists.txt

@@ -29,6 +29,7 @@ set(PYZMQ_LIBSODIUM_URL "" CACHE STRING "full URL to download bundled libsodium"
 set(PYZMQ_LIBSODIUM_CONFIGURE_ARGS "" CACHE STRING "semicolon-separated list of arguments to pass to ./configure for bundled libsodium")
 set(PYZMQ_LIBSODIUM_MSBUILD_ARGS "" CACHE STRING "semicolon-separated list of arguments to pass to msbuild for bundled libsodium")
 set(PYZMQ_LIBSODIUM_VS_VERSION "" CACHE STRING "Visual studio solution version for bundled libsodium (default: detect from MSVC_VERSION)")
+set(PYZMQ_BACKEND "" CACHE STRING "pyzmq backend to build ('cffi' or 'cython'). Default: cffi on PyPy, else Cython.")
 
 if (NOT CMAKE_BUILD_TYPE)
   # default to Release
@@ -57,6 +58,7 @@ foreach(_optname
   PYZMQ_LIBSODIUM_CONFIGURE_ARGS
   PYZMQ_LIBSODIUM_MSBUILD_ARGS
   PYZMQ_LIBSODIUM_VS_VERSION
+  PYZMQ_BACKEND
 )
   if (DEFINED ENV{${_optname}})
     if (_optname MATCHES ".*_ARGS")
@@ -367,8 +369,19 @@ set(EXT_SRC_DIR "${CMAKE_CURRENT_BINARY_DIR}/_src")
 set(ZMQ_BUILDUTILS "${CMAKE_CURRENT_SOURCE_DIR}/buildutils")
 file(MAKE_DIRECTORY "${EXT_SRC_DIR}")
 
-if(Python_INTERPRETER_ID STREQUAL "PyPy")
+if (NOT PYZMQ_BACKEND)
+  if(Python_INTERPRETER_ID STREQUAL "PyPy")
+    set(PYZMQ_BACKEND "cffi")
+  else()
+    set(PYZMQ_BACKEND "cython")
+  endif()
+endif()
+
+if(PYZMQ_BACKEND STREQUAL "cffi")
   message(STATUS "Building CFFI backend")
+  if(NOT Python_INTERPRETER_ID STREQUAL "PyPy")
+    message(WARNING "Building CFFI backend on ${Python_INTERPRETER_ID}, not PyPy. This is not supported and may not work.")
+  endif()
   set(ZMQ_EXT_NAME "_cffi")
 
   set(ZMQ_BACKEND_DEST "zmq/backend/cffi")
@@ -381,8 +394,11 @@ if(Python_INTERPRETER_ID STREQUAL "PyPy")
             "${ZMQ_BUILDUTILS}/build_cffi.py"
             "${ZMQ_C}"
   )
-else()
+elseif(PYZMQ_BACKEND STREQUAL "cython")
   message(STATUS "Building Cython backend")
+  if(NOT Python_INTERPRETER_ID STREQUAL "Python")
+    message(WARNING "Building Cython backend on ${Python_INTERPRETER_ID}, not CPython. This is not supported and may not work.")
+  endif()
   find_program(CYTHON "cython")
 
   set(ZMQ_BACKEND_DEST "zmq/backend/cython")
@@ -400,6 +416,8 @@ else()
             --module-name "zmq.backend.cython._zmq"
             ${ZMQ_PYX}
   )
+else()
+  message(FATAL_ERROR "Unsupported PYZMQ_BACKEND=${PYZMQ_BACKEND}. Must be 'cffi' or 'cython'.")
 endif()
 
 file(MAKE_DIRECTORY ${ZMQ_BACKEND_DEST})

docs/source/changelog.md

@@ -7,6 +7,10 @@ For a full changelog, consult the [git log](https://github.com/zeromq/pyzmq/comm
 
 ## 26
 
+### 26.3
+
+pyzmq 26.3 drops support for Python 3.7 and adds wheels for PyPy 3.11
+
 ### 26.2.1
 
 26.2.1 is a tiny bugfix release

pyproject.toml

@@ -4,7 +4,7 @@ requires = [
   "cffi; implementation_name == 'pypy'",
   "cython>=3.0.0; implementation_name != 'pypy'",
   "packaging",
-  "scikit-build-core",
+  "scikit-build-core>=0.10",
 ]
 build-backend = "scikit_build_core.build"
 
@@ -55,9 +55,13 @@ wheel.license-files = ["licenses/LICENSE*"]
 # 3.15 is required by scikit-build-core
 cmake.version = ">=3.15"
 # only build/install the pyzmq component
-cmake.targets = ["pyzmq"]
+build.targets = ["pyzmq"]
 install.components = ["pyzmq"]
 
+[[tool.scikit-build.overrides]]
+if.env.PYZMQ_BACKEND = "cffi"
+build.requires = ["cffi"]
+
 [tool.ruff]
 
 [tool.ruff.format]

tests/test_message.py

@@ -16,7 +16,7 @@
 import time
 
 import zmq
-from zmq_test_utils import PYPY, BaseZMQTestCase, SkipTest, skip_pypy
+from zmq_test_utils import PYPY, BaseZMQTestCase, SkipTest, skip_cpython_cffi, skip_pypy
 
 # some useful constants:
 
@@ -230,6 +230,7 @@ def test_buffer_out(self):
         assert outb is m.buffer
         assert m.buffer is m.buffer
 
+    @skip_cpython_cffi
     def test_memoryview_shape(self):
         """memoryview shape info"""
         data = "§§¶•ªº˜µ¬˚…∆˙åß∂©œ∑´†≈ç√".encode()
@@ -278,6 +279,7 @@ def test_memoryview(self):
         assert s2 == s
         assert m.bytes == s
 
+    @skip_cpython_cffi
     def test_noncopying_recv(self):
         """check for clobbering message buffers"""
         null = b'\0' * 64
@@ -300,6 +302,7 @@ def test_noncopying_recv(self):
                 assert m2.bytes == ff
                 assert type(m2.bytes) is bytes
 
+    @skip_cpython_cffi
     def test_noncopying_memoryview(self):
         """test non-copying memmoryview messages"""
         null = b'\0' * 64

tests/test_socket.py

@@ -630,7 +630,7 @@ def test_large_send(self):
         # sample the front and back of the received message
         # without checking the whole content
         byte = ord(c)
-        view = memoryview(rcvd)
+        view = memoryview(rcvd.buffer)
         assert len(view) == N
         assert view[0] == byte
         assert view[-1] == byte

tests/zmq_test_utils.py

@@ -27,7 +27,8 @@
     have_gevent = False
 
 
-PYPY = platform.python_implementation() == 'PyPy'
+CFFI = zmq.backend.Socket.__module__.startswith("zmq.backend.cffi.")
+PYPY = platform.python_implementation() == 'PyPy' or CFFI
 
 # -----------------------------------------------------------------------------
 # skip decorators (directly from unittest)
@@ -38,7 +39,11 @@ def _id(x):
     return x
 
 
-skip_pypy = mark.skipif(PYPY, reason="Doesn't work on PyPy")
+skip_pypy = mark.skipif(PYPY, reason="Doesn't work on CFFI backend")
+skip_cpython_cffi = mark.skipif(
+    platform.python_implementation() == 'CPython' and CFFI,
+    reason="CFFI on CPython is unsupported",
+)
 require_zmq_4 = mark.skipif(zmq.zmq_version_info() < (4,), reason="requires zmq >= 4")
 
 # -----------------------------------------------------------------------------

zmq/backend/cffi/__init__.py

@@ -3,6 +3,9 @@
 # Copyright (C) PyZMQ Developers
 # Distributed under the terms of the Modified BSD License.
 
+# for clearer error message on missing cffi
+import cffi  # noqa
+
 from zmq.backend.cffi import _poll, context, devices, error, message, socket, utils
 
 from ._cffi import ffi

zmq/sugar/frame.py

@@ -74,7 +74,7 @@ def __repr__(self):
         nbytes = len(self)
         msg_suffix = ""
         if nbytes > 16:
-            msg_bytes = bytes(memoryview(self)[:12])
+            msg_bytes = bytes(memoryview(self.buffer)[:12])
             if nbytes >= 1e9:
                 unit = "GB"
                 n = nbytes // 1e9