Tighten up some internal type annotations

hypothesis-python/RELEASE.rst

@@ -0,0 +1,3 @@
+RELEASE_TYPE: patch
+
+This patch improves some internal type annotations.

hypothesis-python/src/hypothesis/_settings.py

@@ -148,7 +148,7 @@ def __init__(
         # The intended use is "like **kwargs, but more tractable for tooling".
         max_examples: int = not_set,  # type: ignore
         derandomize: bool = not_set,  # type: ignore
-        database: Union[None, "ExampleDatabase"] = not_set,  # type: ignore
+        database: Optional["ExampleDatabase"] = not_set,  # type: ignore
         verbosity: "Verbosity" = not_set,  # type: ignore
         phases: Collection["Phase"] = not_set,  # type: ignore
         stateful_step_count: int = not_set,  # type: ignore
@@ -160,7 +160,7 @@ def __init__(
         if parent is not None:
             check_type(settings, parent, "parent")
         if derandomize not in (not_set, False):
-            if database not in (not_set, None):
+            if database not in (not_set, None):  # type: ignore
                 raise InvalidArgument(
                     "derandomize=True implies database=None, so passing "
                     f"database={database!r} too is invalid."

hypothesis-python/src/hypothesis/internal/compat.py

@@ -27,19 +27,19 @@
 WINDOWS = platform.system() == "Windows"
 
 
-def escape_unicode_characters(s):
+def escape_unicode_characters(s: str) -> str:
     return codecs.encode(s, "unicode_escape").decode("ascii")
 
 
-def int_from_bytes(data):
+def int_from_bytes(data: typing.Union[bytes, bytearray]) -> int:
     return int.from_bytes(data, "big")
 
 
-def int_to_bytes(i, size):
+def int_to_bytes(i: int, size: int) -> bytes:
     return i.to_bytes(size, "big")
 
 
-def int_to_byte(i):
+def int_to_byte(i: int) -> bytes:
     return bytes([i])
 
 

hypothesis-python/src/hypothesis/internal/conjecture/choicetree.py

@@ -148,7 +148,7 @@ def __init__(self):
         self.n: "Optional[int]" = None
 
     @property
-    def exhausted(self):
+    def exhausted(self) -> bool:
         return self.live_child_count == 0
 
 

hypothesis-python/src/hypothesis/internal/conjecture/data.py

@@ -40,6 +40,7 @@
     from typing_extensions import dataclass_transform
 
     from hypothesis.strategies import SearchStrategy
+    from hypothesis.strategies._internal.strategies import Ex
 else:
 
     def dataclass_transform():
@@ -816,7 +817,7 @@ def __init__(
         self.max_length = max_length
         self.is_find = False
         self.overdraw = 0
-        self.__prefix = prefix
+        self.__prefix = bytes(prefix)
         self.__random = random
 
         assert random is not None or max_length <= len(prefix)
@@ -907,7 +908,7 @@ def note(self, value: Any) -> None:
             value = repr(value)
         self.output += value
 
-    def draw(self, strategy: "SearchStrategy[Any]", label: Optional[int] = None) -> Any:
+    def draw(self, strategy: "SearchStrategy[Ex]", label: Optional[int] = None) -> "Ex":
         if self.is_find and not strategy.supports_find:
             raise InvalidArgument(
                 f"Cannot use strategy {strategy!r} within a call to find "

hypothesis-python/src/hypothesis/internal/filtering.py

@@ -61,7 +61,7 @@ class ConstructivePredicate(NamedTuple):
     predicate: Optional[Predicate]
 
     @classmethod
-    def unchanged(cls, predicate):
+    def unchanged(cls, predicate: Predicate) -> "ConstructivePredicate":
         return cls({}, predicate)
 
 

hypothesis-python/src/hypothesis/internal/floats.py

@@ -10,8 +10,18 @@
 
 import math
 import struct
+from decimal import Decimal
+from fractions import Fraction
 from sys import float_info
-from typing import Callable, Optional
+from typing import Callable, Optional, Union
+
+try:
+    from typing import TypeAlias
+except ImportError:
+    TypeAlias = object  # type: ignore
+
+# See https://github.com/python/mypy/issues/3186 - numbers.Real is wrong!
+Real: TypeAlias = Union[int, float, Fraction, Decimal]
 
 # Format codes for (int, float) sized types, used for byte-wise casts.
 # See https://docs.python.org/3/library/struct.html#format-characters
@@ -36,19 +46,15 @@ def float_of(x, width):
         return reinterpret_bits(float(x), "!e", "!e")
 
 
-def sign(x):
+def is_negative(x: Real) -> bool:
     try:
-        return math.copysign(1.0, x)
+        return math.copysign(1.0, x) < 0
     except TypeError:
         raise TypeError(
             f"Expected float but got {x!r} of type {type(x).__name__}"
         ) from None
 
 
-def is_negative(x):
-    return sign(x) < 0
-
-
 def count_between_floats(x, y, width=64):
     assert x <= y
     if is_negative(x):

hypothesis-python/src/hypothesis/strategies/_internal/core.py

@@ -55,6 +55,7 @@
     integer_range,
 )
 from hypothesis.internal.entropy import get_seeder_and_restorer
+from hypothesis.internal.floats import Real
 from hypothesis.internal.reflection import (
     define_function_signature,
     get_pretty_function_description,
@@ -85,12 +86,7 @@
 from hypothesis.strategies._internal.functions import FunctionStrategy
 from hypothesis.strategies._internal.lazy import LazyStrategy
 from hypothesis.strategies._internal.misc import just, none, nothing
-from hypothesis.strategies._internal.numbers import (
-    IntegersStrategy,
-    Real,
-    floats,
-    integers,
-)
+from hypothesis.strategies._internal.numbers import IntegersStrategy, floats, integers
 from hypothesis.strategies._internal.recursive import RecursiveStrategy
 from hypothesis.strategies._internal.shared import SharedStrategy
 from hypothesis.strategies._internal.strategies import (
@@ -889,7 +885,7 @@ def builds(
             "target to construct."
         )
 
-    if infer in args:
+    if infer in args:  # type: ignore  # we only annotated the allowed types
         # Avoid an implementation nightmare juggling tuples and worse things
         raise InvalidArgument(
             "... was passed as a positional argument to "
@@ -1396,9 +1392,9 @@ def fraction_to_decimal(val):
     special: List[Decimal] = []
     if allow_nan or (allow_nan is None and (None in (min_value, max_value))):
         special.extend(map(Decimal, ("NaN", "-NaN", "sNaN", "-sNaN")))
-    if allow_infinity or (allow_infinity is max_value is None):
+    if allow_infinity or (allow_infinity is None and max_value is None):
         special.append(Decimal("Infinity"))
-    if allow_infinity or (allow_infinity is min_value is None):
+    if allow_infinity or (allow_infinity is None and min_value is None):
         special.append(Decimal("-Infinity"))
     return strat | (sampled_from(special) if special else nothing())
 

hypothesis-python/src/hypothesis/strategies/_internal/numbers.py

@@ -9,10 +9,8 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import math
-from decimal import Decimal
-from fractions import Fraction
 from sys import float_info
-from typing import Optional, Union
+from typing import Optional
 
 from hypothesis.control import reject
 from hypothesis.errors import InvalidArgument
@@ -23,6 +21,7 @@
     get_integer_predicate_bounds,
 )
 from hypothesis.internal.floats import (
+    Real,
     float_of,
     int_to_float,
     is_negative,
@@ -42,8 +41,6 @@
 from hypothesis.strategies._internal.strategies import SearchStrategy
 from hypothesis.strategies._internal.utils import cacheable, defines_strategy
 
-# See https://github.com/python/mypy/issues/3186 - numbers.Real is wrong!
-Real = Union[int, float, Fraction, Decimal]
 ONE_BOUND_INTEGERS_LABEL = d.calc_label_from_name("trying a one-bound int allowing 0")
 
 

mypy.ini

@@ -10,6 +10,7 @@ no_implicit_reexport = True
 follow_imports = silent
 ignore_missing_imports = True
 
+strict_equality = True
 warn_no_return = True
 warn_unused_ignores = True
 warn_unused_configs = True