Mypy warn_unreachable=True (#3312)

pyro/ops/gaussian.py

@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import math
-from typing import Optional, Tuple
+from typing import Optional, Tuple, Union
 
 import torch
 from torch.distributions.utils import lazy_property
@@ -111,7 +111,7 @@ def event_permute(self, perm) -> "Gaussian":
         precision = self.precision[..., perm][..., perm, :]
         return Gaussian(self.log_normalizer, info_vec, precision)
 
-    def __add__(self, other: "Gaussian") -> "Gaussian":
+    def __add__(self, other: Union["Gaussian", int, float, torch.Tensor]) -> "Gaussian":
         """
         Adds two Gaussians in log-density space.
         """
@@ -126,7 +126,7 @@ def __add__(self, other: "Gaussian") -> "Gaussian":
             return Gaussian(self.log_normalizer + other, self.info_vec, self.precision)
         raise ValueError("Unsupported type: {}".format(type(other)))
 
-    def __sub__(self, other: "Gaussian") -> "Gaussian":
+    def __sub__(self, other: Union["Gaussian", int, float, torch.Tensor]) -> "Gaussian":
         if isinstance(other, (int, float, torch.Tensor)):
             return Gaussian(self.log_normalizer - other, self.info_vec, self.precision)
         raise ValueError("Unsupported type: {}".format(type(other)))

pyro/poutine/block_messenger.py

@@ -2,10 +2,12 @@
 # SPDX-License-Identifier: Apache-2.0
 
 from functools import partial
-from typing import Callable, List, Optional
+from typing import TYPE_CHECKING, Callable, List, Optional
 
 from pyro.poutine.messenger import Messenger
-from pyro.poutine.runtime import Message
+
+if TYPE_CHECKING:
+    from pyro.poutine.runtime import Message
 
 
 def _block_fn(
@@ -14,7 +16,7 @@ def _block_fn(
     hide: List[str],
     hide_types: List[str],
     hide_all: bool,
-    msg: Message,
+    msg: "Message",
 ) -> bool:
     # handle observes
     if msg["type"] == "sample" and msg["is_observed"]:
@@ -43,7 +45,7 @@ def _make_default_hide_fn(
     expose: Optional[List[str]],
     hide_types: Optional[List[str]],
     expose_types: Optional[List[str]],
-) -> Callable[[Message], bool]:
+) -> Callable[["Message"], bool]:
     # first, some sanity checks:
     # hide_all and expose_all intersect?
     assert (hide_all is False and expose_all is False) or (
@@ -81,9 +83,11 @@ def _make_default_hide_fn(
     return partial(_block_fn, expose, expose_types, hide, hide_types, hide_all)
 
 
-def _negate_fn(fn: Callable[[Message], Optional[bool]]) -> Callable[[Message], bool]:
+def _negate_fn(
+    fn: Callable[["Message"], Optional[bool]]
+) -> Callable[["Message"], bool]:
     # typed version of lambda msg: not fn(msg)
-    def negated_fn(msg: Message) -> bool:
+    def negated_fn(msg: "Message") -> bool:
         return not fn(msg)
 
     return negated_fn
@@ -140,15 +144,15 @@ class BlockMessenger(Messenger):
 
     def __init__(
         self,
-        hide_fn: Optional[Callable[[Message], Optional[bool]]] = None,
-        expose_fn: Optional[Callable[[Message], Optional[bool]]] = None,
+        hide_fn: Optional[Callable[["Message"], Optional[bool]]] = None,
+        expose_fn: Optional[Callable[["Message"], Optional[bool]]] = None,
         hide_all: bool = True,
         expose_all: bool = False,
         hide: Optional[List[str]] = None,
         expose: Optional[List[str]] = None,
         hide_types: Optional[List[str]] = None,
         expose_types: Optional[List[str]] = None,
-    ):
+    ) -> None:
         super().__init__()
         if not (hide_fn is None or expose_fn is None):
             raise ValueError("Only specify one of hide_fn or expose_fn")
@@ -161,5 +165,5 @@ def __init__(
                 hide_all, expose_all, hide, expose, hide_types, expose_types
             )
 
-    def _process_message(self, msg: Message) -> None:
+    def _process_message(self, msg: "Message") -> None:
         msg["stop"] = bool(self.hide_fn(msg))

pyro/poutine/broadcast_messenger.py

@@ -1,13 +1,15 @@
 # Copyright (c) 2017-2019 Uber Technologies, Inc.
 # SPDX-License-Identifier: Apache-2.0
 
-from typing import List, Optional
+from typing import TYPE_CHECKING, List, Optional
 
 from pyro.distributions.torch_distribution import TorchDistributionMixin
 from pyro.poutine.messenger import Messenger
-from pyro.poutine.runtime import Message
 from pyro.util import ignore_jit_warnings
 
+if TYPE_CHECKING:
+    from pyro.poutine.runtime import Message
+
 
 class BroadcastMessenger(Messenger):
     """
@@ -41,7 +43,7 @@ class BroadcastMessenger(Messenger):
 
     @staticmethod
     @ignore_jit_warnings(["Converting a tensor to a Python boolean"])
-    def _pyro_sample(msg: Message) -> None:
+    def _pyro_sample(msg: "Message") -> None:
         """
         :param msg: current message at a trace site.
         """

pyro/poutine/collapse_messenger.py

@@ -1,16 +1,19 @@
 # Copyright Contributors to the Pyro project.
 # SPDX-License-Identifier: Apache-2.0
 
+
 from functools import reduce, singledispatch
+from typing import TYPE_CHECKING, FrozenSet, Tuple
+
+from typing_extensions import Self
 
 import pyro
 from pyro.distributions.distribution import COERCIONS
 from pyro.ops.linalg import ignore_torch_deprecation_warnings
+from pyro.poutine.runtime import _PYRO_STACK
+from pyro.poutine.trace_messenger import TraceMessenger
 from pyro.poutine.util import site_is_subsample
 
-from .runtime import _PYRO_STACK
-from .trace_messenger import TraceMessenger
-
 # TODO Remove import guard once funsor is a required dependency.
 try:
     import funsor
@@ -24,20 +27,10 @@
     Funsor = type("Funsor", (), {})
     Variable = type("Variable", (), {})
 
+if TYPE_CHECKING:
+    from funsor.distribution import Distribution
 
-@singledispatch
-def _get_free_vars(x):
-    return x
-
-
-@_get_free_vars.register(Variable)
-def _(x):
-    return frozenset((x.name,))
-
-
-@_get_free_vars.register(tuple)
-def _(x, subs):
-    return frozenset().union(*map(_get_free_vars, x))
+    from pyro.poutine.runtime import Message
 
 
 @singledispatch
@@ -92,7 +85,7 @@ class CollapseMessenger(TraceMessenger):
 
     _coerce = None
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs) -> None:
         if CollapseMessenger._coerce is None:
             import funsor
             from funsor.distribution import CoerceDistributionToFunsor
@@ -102,18 +95,20 @@ def __init__(self, *args, **kwargs):
         self._block = False
         super().__init__(*args, **kwargs)
 
-    def _process_message(self, msg):
+    def _process_message(self, msg: "Message") -> None:
         if self._block:
             return
         if site_is_subsample(msg):
             return
         super()._process_message(msg)
 
-    def _pyro_sample(self, msg):
+    def _pyro_sample(self, msg: "Message") -> None:
         # Eagerly convert fn and value to Funsor.
         dim_to_name = {f.dim: f.name for f in msg["cond_indep_stack"]}
         dim_to_name.update(self.preserved_plates)
         msg["fn"] = funsor.to_funsor(msg["fn"], funsor.Real, dim_to_name)
+        if TYPE_CHECKING:
+            assert isinstance(msg["fn"], Distribution)
         domain = msg["fn"].inputs["value"]
         if msg["value"] is None:
             msg["value"] = funsor.Variable(msg["name"], domain)
@@ -123,14 +118,14 @@ def _pyro_sample(self, msg):
         msg["done"] = True
         msg["stop"] = True
 
-    def _pyro_post_sample(self, msg):
+    def _pyro_post_sample(self, msg: "Message") -> None:
         if self._block:
             return
         if site_is_subsample(msg):
             return
         super()._pyro_post_sample(msg)
 
-    def _pyro_barrier(self, msg):
+    def _pyro_barrier(self, msg: "Message") -> None:
         # Get log_prob and record factor.
         name, log_prob, log_joint, sampled_vars = self._get_log_prob()
         self._block = True
@@ -151,14 +146,14 @@ def _pyro_barrier(self, msg):
         value = _substitute(value, samples)
         msg["value"] = value
 
-    def __enter__(self):
+    def __enter__(self) -> Self:
         self.preserved_plates = {
             h.dim: h.name for h in _PYRO_STACK if isinstance(h, pyro.plate)
         }
         COERCIONS.append(self._coerce)
         return super().__enter__()
 
-    def __exit__(self, *args):
+    def __exit__(self, *args) -> None:
         _coerce = COERCIONS.pop()
         assert _coerce is self._coerce
         super().__exit__(*args)
@@ -168,20 +163,20 @@ def __exit__(self, *args):
             pyro.factor(name, log_prob.data)
 
     @ignore_torch_deprecation_warnings()
-    def _get_log_prob(self):
+    def _get_log_prob(self) -> Tuple[str, Funsor, Funsor, FrozenSet[str]]:
         # Convert delayed statements to pyro.factor()
-        reduced_vars = []
+        reduced_vars_list = []
         log_prob_terms = []
-        plates = frozenset()
+        plates: FrozenSet[str] = frozenset()
         for name, site in self.trace.nodes.items():
             if not site["is_observed"]:
-                reduced_vars.append(name)
+                reduced_vars_list.append(name)
             log_prob_terms.append(site["fn"](value=site["value"]))
             plates |= frozenset(
                 f.name for f in site["cond_indep_stack"] if f.vectorized
             )
-        name = reduced_vars[0]
-        reduced_vars = frozenset(reduced_vars)
+        name = reduced_vars_list[0]
+        reduced_vars = frozenset(reduced_vars_list)
         assert log_prob_terms, "nothing to collapse"
         self.trace.nodes.clear()
         reduced_plates = plates - frozenset(self.preserved_plates.values())

pyro/poutine/condition_messenger.py

@@ -1,14 +1,16 @@
 # Copyright (c) 2017-2019 Uber Technologies, Inc.
 # SPDX-License-Identifier: Apache-2.0
 
-from typing import Dict, Union
+from typing import TYPE_CHECKING, Dict, Union
 
 import torch
 
 from pyro.poutine.messenger import Messenger
-from pyro.poutine.runtime import Message
 from pyro.poutine.trace_struct import Trace
 
+if TYPE_CHECKING:
+    from pyro.poutine.runtime import Message
+
 
 class ConditionMessenger(Messenger):
     """
@@ -46,7 +48,7 @@ def __init__(self, data: Union[Dict[str, torch.Tensor], Trace]) -> None:
         super().__init__()
         self.data = data
 
-    def _pyro_sample(self, msg: Message) -> None:
+    def _pyro_sample(self, msg: "Message") -> None:
         """
         :param msg: current message at a trace site.
         :returns: a sample from the stochastic function at the site.

pyro/poutine/do_messenger.py

@@ -49,7 +49,7 @@ class DoMessenger(Messenger):
     :returns: stochastic function decorated with a :class:`~pyro.poutine.do_messenger.DoMessenger`
     """
 
-    def __init__(self, data: Dict[str, Union[torch.Tensor, numbers.Number]]):
+    def __init__(self, data: Dict[str, Union[torch.Tensor, numbers.Number]]) -> None:
         super().__init__()
         self.data = data
         self._intervener_id = str(id(self))

pyro/poutine/guide.py

@@ -2,17 +2,19 @@
 # SPDX-License-Identifier: Apache-2.0
 
 from abc import ABC, abstractmethod
-from typing import Callable, Dict, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Callable, Dict, Optional, Tuple, Union
 
 import torch
 
 import pyro.distributions as dist
-from pyro.distributions.torch_distribution import TorchDistributionMixin
-from pyro.poutine.runtime import Message
 from pyro.poutine.trace_messenger import TraceMessenger
 from pyro.poutine.trace_struct import Trace
 from pyro.poutine.util import prune_subsample_sites, site_is_subsample
 
+if TYPE_CHECKING:
+    from pyro.distributions.torch_distribution import TorchDistributionMixin
+    from pyro.poutine.runtime import Message
+
 
 class GuideMessenger(TraceMessenger, ABC):
     """
@@ -60,12 +62,13 @@ def __call__(self, *args, **kwargs) -> Dict[str, torch.Tensor]:  # type: ignore[
                 samples[name] = site["value"]
         return samples
 
-    def _pyro_sample(self, msg: Message) -> None:
+    def _pyro_sample(self, msg: "Message") -> None:
         if msg["is_observed"] or site_is_subsample(msg):
             return
-        assert isinstance(msg["name"], str)
-        assert isinstance(msg["fn"], TorchDistributionMixin)
-        assert msg["infer"] is not None
+        if TYPE_CHECKING:
+            assert isinstance(msg["name"], str)
+            assert isinstance(msg["fn"], TorchDistributionMixin)
+            assert msg["infer"] is not None
         prior = msg["fn"]
         msg["infer"]["prior"] = prior
         posterior = self.get_posterior(msg["name"], prior)
@@ -75,20 +78,21 @@ def _pyro_sample(self, msg: Message) -> None:
             posterior = posterior.expand(prior.batch_shape)
         msg["fn"] = posterior
 
-    def _pyro_post_sample(self, msg: Message) -> None:
+    def _pyro_post_sample(self, msg: "Message") -> None:
         # Manually apply outer plates.
         assert msg["infer"] is not None
         prior = msg["infer"].get("prior")
         if prior is not None:
-            assert isinstance(msg["fn"], TorchDistributionMixin)
+            if TYPE_CHECKING:
+                assert isinstance(msg["fn"], TorchDistributionMixin)
             if prior.batch_shape != msg["fn"].batch_shape:
                 msg["infer"]["prior"] = prior.expand(msg["fn"].batch_shape)
         return super()._pyro_post_sample(msg)
 
     @abstractmethod
     def get_posterior(
-        self, name: str, prior: TorchDistributionMixin
-    ) -> Union[TorchDistributionMixin, torch.Tensor]:
+        self, name: str, prior: "TorchDistributionMixin"
+    ) -> Union["TorchDistributionMixin", torch.Tensor]:
         """
         Abstract method to compute a posterior distribution or sample a
         posterior value given a prior distribution conditioned on upstream
@@ -148,6 +152,7 @@ def get_traces(self) -> Tuple[Trace, Trace]:
                 del guide_trace.nodes[name]
                 continue
             model_site = model_trace.nodes[name].copy()
+            assert guide_site["infer"] is not None
             model_site["fn"] = guide_site["infer"]["prior"]
             model_trace.nodes[name] = model_site
         return model_trace, guide_trace