Remove allow-pickle option

distributed/diagnostics/tests/test_scheduler_plugin.py

@@ -402,23 +402,6 @@ def start(self, scheduler):
         assert s.foo == "bar"
 
 
-@gen_cluster(client=True, config={"distributed.scheduler.pickle": False})
-async def test_register_plugin_pickle_disabled(c, s, a, b):
-    class Dummy1(SchedulerPlugin):
-        def start(self, scheduler):
-            scheduler.foo = "bar"
-
-    n_plugins = len(s.plugins)
-    with pytest.raises(ValueError) as excinfo:
-        await c.register_plugin(Dummy1())
-
-    msg = str(excinfo.value)
-    assert "disallowed from deserializing" in msg
-    assert "distributed.scheduler.pickle" in msg
-
-    assert n_plugins == len(s.plugins)
-
-
 @gen_cluster(nthreads=[])
 async def test_unregister_scheduler_plugin(s):
     class Plugin(SchedulerPlugin):

distributed/distributed-schema.yaml

@@ -130,16 +130,6 @@ properties:
 
               If we don't receive a heartbeat faster than this then we assume that the worker has died.
 
-          pickle:
-            type: boolean
-            description: |
-              Is the scheduler allowed to deserialize arbitrary bytestrings?
-
-              The scheduler almost never deserializes user data.
-              However there are some cases where the user can submit functions to run directly on the scheduler.
-              This can be convenient for debugging, but also introduces some security risk.
-              By setting this to false we ensure that the user is unable to run arbitrary code on the scheduler.
-
           preload:
             type: array
             description: |

distributed/distributed.yaml

@@ -22,7 +22,6 @@ distributed:
     work-stealing-interval: 100ms  # Callback time for work stealing
     worker-saturation: 1.1 # Send this fraction of nthreads root tasks to workers
     worker-ttl: "5 minutes" # like '60s'. Time to live for workers.  They must heartbeat faster than this
-    pickle: True            # Is the scheduler allowed to deserialize arbitrary bytestrings
     preload: []             # Run custom modules with Scheduler
     preload-argv: []        # See https://docs.dask.org/en/latest/how-to/customize-initialization.html
     unknown-task-duration: 500ms  # Default duration for all tasks with unknown durations ("15m", "2h")

distributed/protocol/core.py

@@ -4,8 +4,6 @@
 
 import msgpack
 
-import dask.config
-
 from distributed.protocol import pickle
 from distributed.protocol.compression import decompress, maybe_compress
 from distributed.protocol.serialize import (
@@ -117,8 +115,6 @@ def _encode_default(obj):
 def loads(frames, deserialize=True, deserializers=None):
     """Transform bytestream back into Python value"""
 
-    allow_pickle = dask.config.get("distributed.scheduler.pickle")
-
     try:
 
         def _decode_default(obj):
@@ -148,13 +144,7 @@ def _decode_default(obj):
                 sub_frames = frames[offset : offset + sub_header["num-sub-frames"]]
                 if "compression" in sub_header:
                     sub_frames = decompress(sub_header, sub_frames)
-                if allow_pickle:
-                    return pickle.loads(sub_header["pickled-obj"], buffers=sub_frames)
-                else:
-                    raise ValueError(
-                        "Unpickle on the Scheduler isn't allowed, set `distributed.scheduler.pickle=true`"
-                    )
-
+                return pickle.loads(sub_header["pickled-obj"], buffers=sub_frames)
             return msgpack_decode_default(obj)
 
         return msgpack.loads(

distributed/protocol/serialize.py

@@ -573,10 +573,6 @@ class ToPickle(Generic[T]):
 
     Both the scheduler and workers with automatically unpickle this
     object on arrival.
-
-    Notice, this requires that the scheduler is allowed to use pickle.
-    If the configuration option "distributed.scheduler.pickle" is set
-    to False, the scheduler will raise an exception instead.
     """
 
     data: T

distributed/scheduler.py

@@ -3533,6 +3533,10 @@ def __init__(
         jupyter=False,
         **kwargs,
     ):
+        if dask.config.get("distributed.scheduler.pickle", default=True) is False:
+            raise RuntimeError(
+                "Pickling can no longer be disabled with the `distributed.scheduler.pickle` option. Please remove this configuration to start the scheduler."
+            )
         if loop is not None:
             warnings.warn(
                 "the loop kwarg to Scheduler is deprecated",
@@ -5868,13 +5872,6 @@ async def register_scheduler_plugin(
         idempotent: bool | None = None,
     ) -> None:
         """Register a plugin on the scheduler."""
-        if not dask.config.get("distributed.scheduler.pickle"):
-            raise ValueError(
-                "Cannot register a scheduler plugin as the scheduler "
-                "has been explicitly disallowed from deserializing "
-                "arbitrary bytestrings using pickle via the "
-                "'distributed.scheduler.pickle' configuration setting."
-            )
         if idempotent is None:
             warnings.warn(
                 "The signature of `Scheduler.register_scheduler_plugin` now requires "
@@ -6922,7 +6919,7 @@ def workers_to_close(
 
         if key is None:
             key = operator.attrgetter("address")
-        if isinstance(key, bytes) and dask.config.get("distributed.scheduler.pickle"):
+        if isinstance(key, bytes):
             key = pickle.loads(key)
 
         groups = groupby(key, self.workers.values())

distributed/tests/test_scheduler.py

@@ -1799,13 +1799,11 @@ def f(dask_scheduler=None):
     assert response == s.address
 
 
-@gen_cluster(client=True, config={"distributed.scheduler.pickle": False})
-async def test_run_on_scheduler_disabled(c, s, a, b):
-    def f(dask_scheduler=None):
-        return dask_scheduler.address
-
-    with pytest.raises(ValueError, match="disallowed from deserializing"):
-        await c._run_on_scheduler(f)
+@gen_test()
+async def test_allow_pickle_false():
+    with dask.config.set({"distributed.scheduler.pickle": False}):
+        with pytest.raises(RuntimeError, match="Pickling can no longer be disabled"):
+            await Scheduler()
 
 
 @gen_cluster()