use enums for constants

simple static declarations, rather than complex compile-time logic

no longer need separate tracking of socket option types either, can be tracked on SocketOption enum itself

.flake8

@@ -1,3 +1,3 @@
 [flake8]
-exclude = .git,dist,docs,zmq/eventloop/minitornado
+exclude = .git,dist,docs,zmq/eventloop/minitornado,buildutils/templates
 ignore = E, F401, F403, F811, F841, W

.github/workflows/test.yml

@@ -150,7 +150,7 @@ jobs:
           sudo ldconfig
           popd
           echo "ZMQ_PREFIX=/usr/local" >> "$GITHUB_ENV"
-          export ZMQ_DRAFT_API=1 >> "$GITHUB_ENV"
+          echo ZMQ_DRAFT_API=1 >> "$GITHUB_ENV"
 
       - name: build pyzmq
         run: |

.pre-commit-config.yaml

@@ -12,6 +12,7 @@ repos:
     rev: 3.9.2
     hooks:
       - id: flake8
+        exclude: ^buildutils/templates/
   - repo: https://github.com/pre-commit/mirrors-mypy
     rev: v0.910
     hooks:

buildutils/build_cffi.py

@@ -9,12 +9,6 @@
 zmq_dir = os.path.join(os.path.dirname(here), 'zmq')
 backend_dir = os.path.join(zmq_dir, 'backend', 'cffi')
 
-# load constant names without zmq being importable
-sys.path.insert(0, os.path.join(zmq_dir, "utils"))
-from constant_names import all_names, no_prefix
-
-sys.path = sys.path[1:]
-
 ffi = cffi.FFI()
 
 
@@ -52,25 +46,6 @@ def load_compiler_config():
 with open(os.path.join(backend_dir, '_cdefs.h')) as f:
     ffi.cdef(f.read())
 
-
-def _make_defines(names):
-    _names = []
-    for name in names:
-        define_line = "#define %s ..." % (name)
-        _names.append(define_line)
-
-    return "\n".join(_names)
-
-
-c_constant_names = ['PYZMQ_DRAFT_API']
-for name in all_names:
-    if no_prefix(name):
-        c_constant_names.append(name)
-    else:
-        c_constant_names.append("ZMQ_" + name)
-
-ffi.cdef(_make_defines(c_constant_names))
-
 with open(os.path.join(here, "_cffi.c")) as f:
     _cffi_c = f.read()
 

buildutils/constants.py

@@ -1,19 +1,20 @@
 """
 script for generating files that involve repetitive updates for zmq constants.
 
+Run as `python setup.py constants`
+
 Run this after updating utils/constant_names
 
 Currently generates the following files from templates:
 
 - constant_enums.pxi
-- constants.pxi
-- zmq_constants.h
-
+- constants.pyi
 """
 
 # Copyright (C) PyZMQ Developers
 # Distributed under the terms of the Modified BSD License.
 
+import enum
 import os
 import sys
 
@@ -24,15 +25,26 @@
 buildutils = os.path.abspath(os.path.dirname(__file__))
 root = pjoin(buildutils, os.path.pardir)
 
-sys.path.insert(0, pjoin(root, 'zmq', 'utils'))
-from constant_names import all_names, no_prefix
+sys.path.insert(0, pjoin(root, 'zmq'))
+import constants
+
+all_names = []
+for name in constants.__all__:
+    item = getattr(constants, name)
+    if isinstance(item, enum.Enum):
+        all_names.append(name)
 
 ifndef_t = """#ifndef {0}
     #define {0} (_PYZMQ_UNDEFINED)
 #endif
 """
 
 
+def no_prefix(name):
+    """does the given constant have a ZMQ_ prefix?"""
+    return name.startswith('E') and not name.startswith('EVENT')
+
+
 def cython_enums():
     """generate `enum: ZMQ_CONST` block for constant_enums.pxi"""
     lines = []
@@ -55,27 +67,40 @@ def ifndefs():
     return dict(ZMQ_IFNDEFS='\n'.join(lines))
 
 
-def constants_pyi():
+def promoted_constants():
     """Generate CONST: int for mypy"""
-    lines = []
-    for name in all_names:
-        lines.append(f"{name}: int")
-
-    return dict(constants="\n".join(lines))
-
-
-def constants_pyx():
-    """generate CONST = ZMQ_CONST and __all__ for constants.pxi"""
-    all_lines = []
-    assign_lines = []
-    for name in all_names:
-        if name == "NULL":
-            # avoid conflict with NULL in Cython
-            assign_lines.append("globals()['NULL'] = ZMQ_NULL")
+    original_lines = []
+    with open(constants.__file__) as f:
+        for line in f.readlines():
+            original_lines.append(line)
+            if "AUTOGENERATED_BELOW_HERE" in line:
+                original_file = "".join(original_lines)
+                break
         else:
-            assign_lines.append('{0} = ZMQ_{0}'.format(name))
-        all_lines.append('  "{0}",'.format(name))
-    return dict(ASSIGNMENTS='\n'.join(assign_lines), ALL='\n'.join(all_lines))
+            raise ValueError("Never encountered AUTOGENERATED_BELOW_HERE")
+
+    global_assignments = []
+    all_lines = ["__all__: List[str] = ["]
+    for cls_name in dir(constants):
+        if cls_name.startswith("_"):
+            continue
+        cls = getattr(constants, cls_name)
+        if not isinstance(cls, type) or not issubclass(cls, enum.Enum):
+            continue
+
+        get_global_name = getattr(cls, "_global_name", lambda name: name)
+        all_lines.append(f'    "{cls_name}",')
+        for key in cls.__members__:
+            global_name = get_global_name(key)
+            all_lines.append(f'    "{global_name}",')
+            global_assignments.append(f"{global_name}: int = {cls_name}.{key}")
+    all_lines.append("]")
+
+    return dict(
+        original_file=original_file,
+        global_assignments="\n".join(global_assignments),
+        __all__="\n".join(all_lines),
+    )
 
 
 def generate_file(fname, ns_func, dest_dir="."):
@@ -94,12 +119,7 @@ def render_constants():
     generate_file(
         "constant_enums.pxi", cython_enums, pjoin(root, 'zmq', 'backend', 'cython')
     )
-    generate_file(
-        "constants.pxi", constants_pyx, pjoin(root, 'zmq', 'backend', 'cython')
-    )
-    generate_file("constants.pyi", constants_pyi, pjoin(root, 'zmq', 'sugar'))
-    generate_file("constants.pyi", constants_pyi, pjoin(root, 'zmq', 'backend'))
-    generate_file("zmq_constants.h", ifndefs, pjoin(root, 'zmq', 'utils'))
+    generate_file("constants.py", promoted_constants, pjoin(root, 'zmq'))
 
 
 if __name__ == '__main__':

buildutils/templates/constant_enums.pxi

@@ -1,3 +1,7 @@
 cdef extern from "zmq.h" nogil:
     enum: PYZMQ_DRAFT_API
+    enum: ZMQ_VERSION
+    enum: ZMQ_VERSION_MAJOR
+    enum: ZMQ_VERSION_MINOR
+    enum: ZMQ_VERSION_PATCH
     {ZMQ_ENUMS}

buildutils/templates/constants.py

@@ -0,0 +1,5 @@
+{original_file}
+
+{global_assignments}
+
+{__all__}

setup.py

@@ -1184,7 +1184,6 @@ def makename(path, ext):
 
 submodules = {
     'backend.cython': {
-        'constants': [libzmq, pxi('backend', 'cython', 'constants')],
         'error': [libzmq, checkrc],
         '_poll': [libzmq, socket, context, checkrc],
         'utils': [libzmq, checkrc],

zmq/__init__.py

@@ -102,9 +102,11 @@ def _libs_on_path():
 with _libs_on_path():
     from zmq import backend
 
-from zmq.backend import *
+from . import constants  # noqa
+from .constants import *  # noqa
+from zmq.backend import *  # noqa
 from zmq import sugar
-from zmq.sugar import *
+from zmq.sugar import *  # noqa
 
 
 def get_includes():
@@ -129,4 +131,13 @@ def get_library_dirs():
 
 
 COPY_THRESHOLD = 65536
-__all__ = ['get_includes', 'COPY_THRESHOLD'] + sugar.__all__ + backend.__all__
+DRAFT_API = backend.has("draft")
+__all__ = (
+    [
+        'get_includes',
+        'COPY_THRESHOLD',
+        'DRAFT_API',
+    ]
+    + sugar.__all__
+    + backend.__all__
+)

zmq/__init__.pyi

@@ -5,6 +5,7 @@ from . import sugar
 
 from .error import *
 from .sugar import *
+from .constants import *
 
 # mypy doesn't like overwriting symbols with * so be explicit
 # about what comes from backend, not from sugar
@@ -25,6 +26,7 @@ from .backend import (
 )
 
 COPY_THRESHOLD: int
+DRAFT_API: bool
 
 def get_includes() -> List[str]: ...
 def get_library_dirs() -> List[str]: ...

zmq/backend/__init__.py

@@ -6,7 +6,6 @@
 
 import os
 import platform
-import sys
 
 from .select import public_api, select_backend
 

zmq/backend/cffi/__init__.py

@@ -4,7 +4,6 @@
 # Distributed under the terms of the Modified BSD License.
 
 from zmq.backend.cffi import (
-    constants,
     error,
     message,
     context,
@@ -28,10 +27,9 @@ def zmq_version_info():
 
 
 __all__ = ["zmq_version_info"]
-for submod in (constants, error, message, context, socket, _poll, devices, utils):
+for submod in (error, message, context, socket, _poll, devices, utils):
     __all__.extend(submod.__all__)
 
-from .constants import *
 from .error import *
 from .message import *
 from .context import *

zmq/backend/cffi/context.py

@@ -6,8 +6,7 @@
 
 from ._cffi import lib as C, ffi
 
-from .constants import EINVAL, IO_THREADS, LINGER
-
+from zmq.constants import EINVAL, IO_THREADS, LINGER
 from zmq.error import ZMQError, InterruptedSystemCall, _check_rc
 
 

zmq/backend/cffi/message.py

@@ -8,9 +8,9 @@
 from threading import Event
 
 from ._cffi import ffi, lib as C
-from .constants import ETERM
 
 import zmq
+from zmq.constants import ETERM
 from zmq.utils.strtypes import unicode
 import zmq.error