support for Python 3.11

.github/workflows/test.yml

@@ -36,7 +36,7 @@ jobs:
             cluster_type: slurm
             container: slurmctld
           - python: "3.7"
-          - python: "3.8"
+          - python: "3.10"
             env:
               IPP_CONTROLLER_IP: "*"
           - python: "3.9"
@@ -46,6 +46,7 @@ jobs:
             runs_on: windows-2019
           - python: "3.9"
             runs_on: macos-10.15
+          - python: "3.11.0-beta.3"
 
     steps:
       - uses: actions/checkout@v2
@@ -120,7 +121,12 @@ jobs:
 
       - name: Install Python dependencies
         run: |
-          pip install --pre --upgrade ipyparallel[test] distributed joblib codecov
+          pip install --pre --upgrade ipyparallel[test] codecov
+
+      - name: Install extra Python packages
+        if: ${{ ! startsWith(matrix.python, '3.11') }}
+        run: |
+          pip install distributed joblib
           pip install --only-binary :all: matplotlib || echo "no matplotlib"
 
       - name: Show environment

ipyparallel/engine/kernel.py

@@ -211,7 +211,10 @@ def do_apply(self, content, bufs, msg_id, reply_metadata):
         except BaseException as e:
             # invoke IPython traceback formatting
             # this sends the 'error' message
-            shell.showtraceback()
+            try:
+                shell.showtraceback()
+            except Exception as tb_error:
+                self.log.error(f"Failed to show traceback for {e}: {tb_error}")
 
             try:
                 str_evalue = str(e)

ipyparallel/serialize/codeutil.py

@@ -9,41 +9,58 @@
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
+import copyreg
+import inspect
 import sys
 import types
 
-try:
-    import copyreg  # Py 3
-except ImportError:
-    import copy_reg as copyreg  # Py 2
-
 
 def code_ctor(*args):
     return types.CodeType(*args)
 
 
-def reduce_code(co):
-    args = [
-        co.co_argcount,
-        co.co_nlocals,
-        co.co_stacksize,
-        co.co_flags,
-        co.co_code,
-        co.co_consts,
-        co.co_names,
-        co.co_varnames,
-        co.co_filename,
-        co.co_name,
-        co.co_firstlineno,
-        co.co_lnotab,
-        co.co_freevars,
-        co.co_cellvars,
+# map CodeType constructor args to code co_ attribute names
+# (they _almost_ all match, and new ones probably will)
+_code_attr_map = {
+    "codestring": "code",
+    "constants": "consts",
+}
+# pass every supported arg to the code constructor
+# this should be more forward-compatible
+if sys.version_info >= (3, 10):
+    _code_attr_names = tuple(
+        _code_attr_map.get(name, name)
+        for name, param in inspect.signature(types.CodeType).parameters.items()
+        if param.POSITIONAL_ONLY or param.POSITIONAL_OR_KEYWORD
+    )
+else:
+    # can't inspect types.CodeType on Python < 3.10
+    _code_attr_names = [
+        "argcount",
+        "kwonlyargcount",
+        "nlocals",
+        "stacksize",
+        "flags",
+        "code",
+        "consts",
+        "names",
+        "varnames",
+        "filename",
+        "name",
+        "firstlineno",
+        "lnotab",
+        "freevars",
+        "cellvars",
     ]
-    if sys.version_info[0] >= 3:
-        args.insert(1, co.co_kwonlyargcount)
-    if sys.version_info > (3, 8):
-        args.insert(1, co.co_posonlyargcount)
-    return code_ctor, tuple(args)
+    if hasattr(types.CodeType, "co_posonlyargcount"):
+        _code_attr_names.insert(1, "posonlyargcount")
+
+    _code_attr_names = tuple(_code_attr_names)
+
+
+def reduce_code(obj):
+    """codeobject reducer"""
+    return code_ctor, tuple(getattr(obj, f'co_{name}') for name in _code_attr_names)
 
 
 copyreg.pickle(types.CodeType, reduce_code)

ipyparallel/tests/clienttest.py

@@ -197,7 +197,8 @@ def _sigalarm(sig, frame):
         self.engines = []
 
     def tearDown(self):
-        self.client[:].use_pickle()
+        if len(self.client):
+            self.client[:].use_pickle()
 
         # self.client.clear(block=True)
         # close fds:

pyproject.toml

@@ -124,7 +124,8 @@ testpaths = [
     "ipyparallel/tests"
 ]
 filterwarnings = [
-  "error",
+  "error:::ipy*",
+  "error:::jupyter*",
   "ignore:unclosed event loop:ResourceWarning",
   "ignore:unclosed socket <zmq.Socket:ResourceWarning",
   "ignore:unclosed <socket.socket:ResourceWarning",