Add support for Python 3.13

.github/workflows/tests.yaml

@@ -26,7 +26,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        environment: [mindeps, "3.10", "3.11", "3.12"]
+        environment: [mindeps, "3.10", "3.11", "3.12", "3.13"]
         label: [default]
         extra_packages: [null]
         # Cherry-pick test modules to split the overall runtime roughly in half
@@ -40,6 +40,8 @@ jobs:
             environment: "3.10"
           - os: macos-latest
             environment: "3.11"
+          - os: macos-latest
+            environment: "3.13"
 
           - os: windows-latest
             environment: mindeps
@@ -242,7 +244,7 @@ jobs:
           set -o pipefail
           mkdir reports
 
-          pytest distributed \
+          python -m pytest distributed \
             -m "not avoid_ci and ${{ matrix.partition }}" --runslow \
             --leaks=fds,processes,threads \
             --junitxml reports/pytest.xml -o junit_suite_name=$TEST_ID \

continuous_integration/environment-3.13.yaml

@@ -0,0 +1,56 @@
+name: dask-distributed-313
+channels:
+  - conda-forge
+dependencies:
+  - python=3.13
+  - packaging
+  - pip
+  - asyncssh
+  - bokeh>3
+  - click
+  - cloudpickle
+  - coverage
+  - dask  # overridden by git tip below
+  - filesystem-spec  # overridden by git tip below
+  - gilknocker
+  - h5py
+  - ipykernel
+  - ipywidgets
+  - jinja2
+  - jupyter-server-proxy
+  - jupyterlab
+  - locket
+  - msgpack-python
+  - netcdf4
+  - paramiko
+  - pre-commit
+  - prometheus_client
+  - psutil
+  - pyarrow
+  - pytest
+  - pytest-cov
+  - pytest-faulthandler
+  - pytest-repeat
+  - pytest-rerunfailures
+  - pytest-timeout
+  - requests
+  - s3fs  # overridden by git tip below
+  - scikit-learn
+  - scipy
+  - sortedcollections
+  - tblib
+  - toolz
+  # - tornado # Using pip below until 6.4.2 is on conda-forge
+  - zict  # overridden by git tip below
+  - zstandard
+  # Temporary fix for https://github.com/pypa/setuptools/issues/4496
+  - setuptools < 71
+  - pip:
+      - git+https://github.com/dask/dask
+      - git+https://github.com/dask/dask-expr
+      - git+https://github.com/dask/zict
+      # Revert after https://github.com/dask/distributed/issues/8614 is fixed
+      # - git+https://github.com/dask/s3fs
+      # - git+https://github.com/fsspec/filesystem_spec
+      - keras
+      - tornado>=6.4.2

distributed/dashboard/tests/test_scheduler_bokeh.py

@@ -1144,6 +1144,7 @@ async def test_https_support(c, s, a, b):
 
     ctx = ssl.create_default_context()
     ctx.load_verify_locations(get_cert("tls-ca-cert.pem"))
+    ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT
 
     http_client = AsyncHTTPClient()
     response = await http_client.fetch(

distributed/security.py

@@ -326,6 +326,8 @@ def _get_tls_context(self, tls, purpose):
             # IP addresses rather than hostnames
             ctx.check_hostname = False
 
+            ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT
+
             if tls.get("ciphers"):
                 ctx.set_ciphers(tls.get("ciphers"))
 

distributed/tests/test_client.py

@@ -1704,6 +1704,10 @@ async def test_upload_file_no_extension(c, s, a, b):
         await c.upload_file(fn)
 
 
+@pytest.mark.skipif(
+    sys.version_info >= (3, 13),
+    reason="Upstream issue in CPython. See https://github.com/dask/distributed/issues/8708 and https://github.com/python/cpython/issues/121342.",
+)
 @gen_cluster(client=True)
 async def test_upload_file_zip(c, s, a, b):
     def g():

distributed/tests/test_metrics.py

@@ -8,7 +8,6 @@
 import pytest
 
 from distributed import metrics
-from distributed.compatibility import WINDOWS
 from distributed.utils import offload
 from distributed.utils_test import gen_test
 
@@ -30,7 +29,8 @@ def test_wall_clock(name):
 
 @pytest.mark.slow
 @pytest.mark.skipif(
-    not WINDOWS, reason="WindowsTime doesn't work with high accuracy base timer"
+    not isinstance(metrics.time, metrics._WindowsTime),
+    reason="WindowsTime doesn't work with high accuracy base timer",
 )
 def test_monotonic():
     t = metrics._WindowsTime(time.monotonic, is_monotonic=True, resync_every=0.1).time

distributed/utils_test.py

@@ -54,7 +54,7 @@
 )
 from distributed.deploy import SpecCluster
 from distributed.diagnostics.plugin import WorkerPlugin
-from distributed.metrics import context_meter, time
+from distributed.metrics import _WindowsTime, context_meter, time
 from distributed.nanny import Nanny
 from distributed.node import ServerNode
 from distributed.proctitle import enable_proctitle_on_children
@@ -1541,6 +1541,7 @@ def get_server_ssl_context(
     ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH, cafile=get_cert(ca_file))
     ctx.check_hostname = False
     ctx.verify_mode = ssl.CERT_REQUIRED
+    ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT
     ctx.load_cert_chain(get_cert(certfile), get_cert(keyfile))
     return ctx
 
@@ -1551,6 +1552,7 @@ def get_client_ssl_context(
     ctx = ssl.create_default_context(ssl.Purpose.SERVER_AUTH, cafile=get_cert(ca_file))
     ctx.check_hostname = False
     ctx.verify_mode = ssl.CERT_REQUIRED
+    ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT
     ctx.load_cert_chain(get_cert(certfile), get_cert(keyfile))
     return ctx
 
@@ -2605,14 +2607,14 @@ def no_time_resync():
     """Temporarily disable the automatic resync of distributed.metrics._WindowsTime
     which, every 10 minutes, can cause time() to go backwards a few milliseconds.
 
-    On Linux and MacOSX, this fixture is a no-op.
+    On Linux, MacOSX, and Windows with Python 3.13+ this fixture is a no-op.
 
     See also
     --------
     NoSchedulerDelayWorker
     padded_time
     """
-    if WINDOWS:
+    if isinstance(time, _WindowsTime):
         time()  # Initialize or refresh delta
         bak = time.__self__.next_resync
         time.__self__.next_resync = float("inf")

pyproject.toml

@@ -19,6 +19,7 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "Topic :: Scientific/Engineering",
     "Topic :: System :: Distributed Computing",
 ]