PYTHON-2926 Updated signature of Binary.from_vector to take a BinaryVector (mongodb#1963)

Author: caseyclements

bson/binary.py

@@ -16,7 +16,7 @@
 import struct
 from dataclasses import dataclass
 from enum import Enum
-from typing import TYPE_CHECKING, Any, Sequence, Tuple, Type, Union
+from typing import TYPE_CHECKING, Any, Optional, Sequence, Tuple, Type, Union
 from uuid import UUID
 
 """Tools for representing BSON binary data.
@@ -400,24 +400,35 @@ def as_uuid(self, uuid_representation: int = UuidRepresentation.STANDARD) -> UUI
     @classmethod
     def from_vector(
         cls: Type[Binary],
-        vector: list[int, float],
-        dtype: BinaryVectorDtype,
-        padding: int = 0,
+        vector: Union[BinaryVector, list[int, float]],
+        dtype: Optional[BinaryVectorDtype] = None,
+        padding: Optional[int] = None,
     ) -> Binary:
-        """**(BETA)** Create a BSON :class:`~bson.binary.Binary` of Vector subtype from a list of Numbers.
+        """**(BETA)** Create a BSON :class:`~bson.binary.Binary` of Vector subtype.
 
         To interpret the representation of the numbers, a data type must be included.
         See :class:`~bson.binary.BinaryVectorDtype` for available types and descriptions.
 
         The dtype and padding are prepended to the binary data's value.
 
-        :param vector: List of values
+        :param vector: Either a List of values, or a :class:`~bson.binary.BinaryVector` dataclass.
         :param dtype: Data type of the values
         :param padding: For fractional bytes, number of bits to ignore at end of vector.
         :return: Binary packed data identified by dtype and padding.
 
         .. versionadded:: 4.10
         """
+        if isinstance(vector, BinaryVector):
+            if dtype or padding:
+                raise ValueError(
+                    "The first argument, vector, has type BinaryVector. "
+                    "dtype or padding cannot be separately defined, but were."
+                )
+            dtype = vector.dtype
+            padding = vector.padding
+            vector = vector.data  # type: ignore
+
+        padding = 0 if padding is None else padding
         if dtype == BinaryVectorDtype.INT8:  # pack ints in [-128, 127] as signed int8
             format_str = "b"
             if padding:
@@ -432,7 +443,7 @@ def from_vector(
             raise NotImplementedError("%s not yet supported" % dtype)
 
         metadata = struct.pack("<sB", dtype.value, padding)
-        data = struct.pack(f"<{len(vector)}{format_str}", *vector)
+        data = struct.pack(f"<{len(vector)}{format_str}", *vector)  # type: ignore
         return cls(metadata + data, subtype=VECTOR_SUBTYPE)
 
     def as_vector(self) -> BinaryVector:

test/test_bson.py

@@ -51,7 +51,13 @@
     is_valid,
     json_util,
 )
-from bson.binary import USER_DEFINED_SUBTYPE, Binary, BinaryVectorDtype, UuidRepresentation
+from bson.binary import (
+    USER_DEFINED_SUBTYPE,
+    Binary,
+    BinaryVector,
+    BinaryVectorDtype,
+    UuidRepresentation,
+)
 from bson.code import Code
 from bson.codec_options import CodecOptions, DatetimeConversion
 from bson.datetime_ms import _DATETIME_ERROR_SUGGESTION
@@ -785,6 +791,18 @@ def test_vector(self):
             else:
                 self.fail("Failed to raise an exception.")
 
+        # Test form of Binary.from_vector(BinaryVector)
+
+        assert padded_vec == Binary.from_vector(
+            BinaryVector(list_vector, BinaryVectorDtype.PACKED_BIT, padding)
+        )
+        assert binary_vector == Binary.from_vector(
+            BinaryVector(list_vector, BinaryVectorDtype.INT8)
+        )
+        assert float_binary == Binary.from_vector(
+            BinaryVector(list_vector, BinaryVectorDtype.FLOAT32)
+        )
+
     def test_unicode_regex(self):
         """Tests we do not get a segfault for C extension on unicode RegExs.
         This had been happening.