From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Mon, 19 Sep 2022 00:42:34 +0000 (+0100)
Subject: fix: annotate every dumper to return Optional[Buffer]
X-Git-Tag: 3.2.0~20^2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=747abad83cb8454ddb605da332eb1b493370abf5;p=thirdparty%2Fpsycopg.git

fix: annotate every dumper to return Optional[Buffer]

Even if these classes never return None, this allows to create
subclasses returning None without making Mypy unhappy.

Similarly, annotate quote() methods as returning Buffer to allow
subclasses to return other types.
---

diff --git a/psycopg/psycopg/dbapi20.py b/psycopg/psycopg/dbapi20.py
index aab4c822f..919b0506c 100644
--- a/psycopg/psycopg/dbapi20.py
+++ b/psycopg/psycopg/dbapi20.py
@@ -7,7 +7,7 @@ Compatibility objects with DBAPI 2.0
 import time
 import datetime as dt
 from math import floor
-from typing import Any, Sequence, Union
+from typing import Any, Optional, Sequence, Union
 
 from . import _oids
 from .abc import AdaptContext, Buffer
@@ -76,7 +76,7 @@ class Binary:
 
 
 class BinaryBinaryDumper(BytesBinaryDumper):
-    def dump(self, obj: Union[Buffer, Binary]) -> Buffer:
+    def dump(self, obj: Union[Buffer, Binary]) -> Optional[Buffer]:
         if isinstance(obj, Binary):
             return super().dump(obj.obj)
         else:
@@ -84,7 +84,7 @@ class BinaryBinaryDumper(BytesBinaryDumper):
 
 
 class BinaryTextDumper(BytesDumper):
-    def dump(self, obj: Union[Buffer, Binary]) -> Buffer:
+    def dump(self, obj: Union[Buffer, Binary]) -> Optional[Buffer]:
         if isinstance(obj, Binary):
             return super().dump(obj.obj)
         else:
diff --git a/psycopg/psycopg/types/array.py b/psycopg/psycopg/types/array.py
index d4a5dc0b2..23afc7d9f 100644
--- a/psycopg/psycopg/types/array.py
+++ b/psycopg/psycopg/types/array.py
@@ -153,7 +153,7 @@ class ListDumper(BaseListDumper):
     # backslash-escaped.
     _re_esc = re.compile(rb'(["\\])')
 
-    def dump(self, obj: List[Any]) -> bytes:
+    def dump(self, obj: List[Any]) -> Optional[Buffer]:
         tokens: List[Buffer] = []
         needs_quotes = _get_needs_quotes_regexp(self.delimiter).search
 
@@ -245,7 +245,7 @@ class ListBinaryDumper(BaseListDumper):
 
         return dumper
 
-    def dump(self, obj: List[Any]) -> bytes:
+    def dump(self, obj: List[Any]) -> Optional[Buffer]:
         # Postgres won't take unknown for element oid: fall back on text
         sub_oid = self.sub_dumper and self.sub_dumper.oid or TEXT_OID
 
diff --git a/psycopg/psycopg/types/bool.py b/psycopg/psycopg/types/bool.py
index 2ad53c2f4..c05679354 100644
--- a/psycopg/psycopg/types/bool.py
+++ b/psycopg/psycopg/types/bool.py
@@ -5,6 +5,7 @@ Adapters for booleans.
 # Copyright (C) 2020 The Psycopg Team
 
 from .. import _oids
+from typing import Optional
 from ..pq import Format
 from ..abc import AdaptContext
 from ..adapt import Buffer, Dumper, Loader
@@ -13,10 +14,10 @@ from ..adapt import Buffer, Dumper, Loader
 class BoolDumper(Dumper):
     oid = _oids.BOOL_OID
 
-    def dump(self, obj: bool) -> bytes:
+    def dump(self, obj: bool) -> Optional[Buffer]:
         return b"t" if obj else b"f"
 
-    def quote(self, obj: bool) -> bytes:
+    def quote(self, obj: bool) -> Buffer:
         return b"true" if obj else b"false"
 
 
@@ -24,7 +25,7 @@ class BoolBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.BOOL_OID
 
-    def dump(self, obj: bool) -> bytes:
+    def dump(self, obj: bool) -> Optional[Buffer]:
         return b"\x01" if obj else b"\x00"
 
 
diff --git a/psycopg/psycopg/types/composite.py b/psycopg/psycopg/types/composite.py
index d116273c4..d3f41b675 100644
--- a/psycopg/psycopg/types/composite.py
+++ b/psycopg/psycopg/types/composite.py
@@ -14,7 +14,7 @@ from .. import pq
 from .. import abc
 from .. import sql
 from .. import postgres
-from ..adapt import Transformer, PyFormat, RecursiveDumper, Loader, Dumper
+from ..adapt import Transformer, PyFormat, RecursiveDumper, Loader, Dumper, Buffer
 from .._oids import TEXT_OID
 from .._compat import cache
 from .._struct import pack_len, unpack_len
@@ -117,7 +117,7 @@ class TupleDumper(SequenceDumper):
     # Should be this, but it doesn't work
     # oid = _oids.RECORD_OID
 
-    def dump(self, obj: Tuple[Any, ...]) -> bytes:
+    def dump(self, obj: Tuple[Any, ...]) -> Optional[Buffer]:
         return self._dump_sequence(obj, b"(", b")", b",")
 
 
@@ -140,7 +140,7 @@ class TupleBinaryDumper(Dumper):
         nfields = len(self._field_types)
         self._formats = (PyFormat.from_pq(self.format),) * nfields
 
-    def dump(self, obj: Tuple[Any, ...]) -> bytearray:
+    def dump(self, obj: Tuple[Any, ...]) -> Optional[Buffer]:
         out = bytearray(pack_len(len(obj)))
         adapted = self._tx.dump_sequence(obj, self._formats)
         for i in range(len(obj)):
diff --git a/psycopg/psycopg/types/datetime.py b/psycopg/psycopg/types/datetime.py
index e5629a9dd..b3bfa1b8b 100644
--- a/psycopg/psycopg/types/datetime.py
+++ b/psycopg/psycopg/types/datetime.py
@@ -40,7 +40,7 @@ _py_date_min_days = date.min.toordinal()
 class DateDumper(Dumper):
     oid = _oids.DATE_OID
 
-    def dump(self, obj: date) -> bytes:
+    def dump(self, obj: date) -> Optional[Buffer]:
         # NOTE: whatever the PostgreSQL DateStyle input format (DMY, MDY, YMD)
         # the YYYY-MM-DD is always understood correctly.
         return str(obj).encode()
@@ -50,7 +50,7 @@ class DateBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.DATE_OID
 
-    def dump(self, obj: date) -> bytes:
+    def dump(self, obj: date) -> Optional[Buffer]:
         days = obj.toordinal() - _pg_date_epoch_days
         return pack_int4(days)
 
@@ -77,7 +77,7 @@ class _BaseTimeDumper(Dumper):
 
 
 class _BaseTimeTextDumper(_BaseTimeDumper):
-    def dump(self, obj: time) -> bytes:
+    def dump(self, obj: time) -> Optional[Buffer]:
         return str(obj).encode()
 
 
@@ -94,7 +94,7 @@ class TimeDumper(_BaseTimeTextDumper):
 class TimeTzDumper(_BaseTimeTextDumper):
     oid = _oids.TIMETZ_OID
 
-    def dump(self, obj: time) -> bytes:
+    def dump(self, obj: time) -> Optional[Buffer]:
         self._get_offset(obj)
         return super().dump(obj)
 
@@ -103,7 +103,7 @@ class TimeBinaryDumper(_BaseTimeDumper):
     format = Format.BINARY
     oid = _oids.TIME_OID
 
-    def dump(self, obj: time) -> bytes:
+    def dump(self, obj: time) -> Optional[Buffer]:
         us = obj.microsecond + 1_000_000 * (
             obj.second + 60 * (obj.minute + 60 * obj.hour)
         )
@@ -120,7 +120,7 @@ class TimeTzBinaryDumper(_BaseTimeDumper):
     format = Format.BINARY
     oid = _oids.TIMETZ_OID
 
-    def dump(self, obj: time) -> bytes:
+    def dump(self, obj: time) -> Optional[Buffer]:
         us = obj.microsecond + 1_000_000 * (
             obj.second + 60 * (obj.minute + 60 * obj.hour)
         )
@@ -142,7 +142,7 @@ class _BaseDatetimeDumper(Dumper):
 
 
 class _BaseDatetimeTextDumper(_BaseDatetimeDumper):
-    def dump(self, obj: datetime) -> bytes:
+    def dump(self, obj: datetime) -> Optional[Buffer]:
         # NOTE: whatever the PostgreSQL DateStyle input format (DMY, MDY, YMD)
         # the YYYY-MM-DD is always understood correctly.
         return str(obj).encode()
@@ -166,7 +166,7 @@ class DatetimeBinaryDumper(_BaseDatetimeDumper):
     format = Format.BINARY
     oid = _oids.TIMESTAMPTZ_OID
 
-    def dump(self, obj: datetime) -> bytes:
+    def dump(self, obj: datetime) -> Optional[Buffer]:
         delta = obj - _pg_datetimetz_epoch
         micros = delta.microseconds + 1_000_000 * (86_400 * delta.days + delta.seconds)
         return pack_int8(micros)
@@ -182,7 +182,7 @@ class DatetimeNoTzBinaryDumper(_BaseDatetimeDumper):
     format = Format.BINARY
     oid = _oids.TIMESTAMP_OID
 
-    def dump(self, obj: datetime) -> bytes:
+    def dump(self, obj: datetime) -> Optional[Buffer]:
         delta = obj - _pg_datetime_epoch
         micros = delta.microseconds + 1_000_000 * (86_400 * delta.days + delta.seconds)
         return pack_int8(micros)
@@ -198,7 +198,7 @@ class TimedeltaDumper(Dumper):
         else:
             self._dump_method = self._dump_any
 
-    def dump(self, obj: timedelta) -> bytes:
+    def dump(self, obj: timedelta) -> Optional[Buffer]:
         return self._dump_method(self, obj)
 
     @staticmethod
@@ -222,7 +222,7 @@ class TimedeltaBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.INTERVAL_OID
 
-    def dump(self, obj: timedelta) -> bytes:
+    def dump(self, obj: timedelta) -> Optional[Buffer]:
         micros = 1_000_000 * obj.seconds + obj.microseconds
         return _pack_interval(micros, obj.days, 0)
 
diff --git a/psycopg/psycopg/types/enum.py b/psycopg/psycopg/types/enum.py
index 6e20dd3ce..04616419d 100644
--- a/psycopg/psycopg/types/enum.py
+++ b/psycopg/psycopg/types/enum.py
@@ -98,7 +98,7 @@ class _BaseEnumDumper(Dumper, Generic[E]):
     enum: Type[E]
     _dump_map: EnumDumpMap[E]
 
-    def dump(self, value: E) -> Buffer:
+    def dump(self, value: E) -> Optional[Buffer]:
         return self._dump_map[value]
 
 
@@ -111,7 +111,7 @@ class EnumDumper(Dumper):
         super().__init__(cls, context)
         self._encoding = conn_encoding(self.connection)
 
-    def dump(self, value: E) -> Buffer:
+    def dump(self, value: E) -> Optional[Buffer]:
         return value.name.encode(self._encoding)
 
 
diff --git a/psycopg/psycopg/types/json.py b/psycopg/psycopg/types/json.py
index df571e43c..0f5651e71 100644
--- a/psycopg/psycopg/types/json.py
+++ b/psycopg/psycopg/types/json.py
@@ -142,7 +142,7 @@ class _JsonDumper(Dumper):
         super().__init__(cls, context)
         self.dumps = self.__class__._dumps
 
-    def dump(self, obj: Any) -> bytes:
+    def dump(self, obj: Any) -> Optional[Buffer]:
         if isinstance(obj, _JsonWrapper):
             dumps = obj.dumps or self.dumps
             obj = obj.obj
@@ -171,7 +171,7 @@ class JsonbBinaryDumper(_JsonDumper):
     format = Format.BINARY
     oid = _oids.JSONB_OID
 
-    def dump(self, obj: Any) -> bytes:
+    def dump(self, obj: Any) -> Optional[Buffer]:
         return b"\x01" + super().dump(obj)
 
 
diff --git a/psycopg/psycopg/types/multirange.py b/psycopg/psycopg/types/multirange.py
index 51f61d1a7..d37681009 100644
--- a/psycopg/psycopg/types/multirange.py
+++ b/psycopg/psycopg/types/multirange.py
@@ -256,7 +256,7 @@ class MultirangeDumper(BaseMultirangeDumper):
     The dumper can upgrade to one specific for a different range type.
     """
 
-    def dump(self, obj: Multirange[Any]) -> Buffer:
+    def dump(self, obj: Multirange[Any]) -> Optional[Buffer]:
         if not obj:
             return b"{}"
 
@@ -277,7 +277,7 @@ class MultirangeDumper(BaseMultirangeDumper):
 class MultirangeBinaryDumper(BaseMultirangeDumper):
     format = Format.BINARY
 
-    def dump(self, obj: Multirange[Any]) -> Buffer:
+    def dump(self, obj: Multirange[Any]) -> Optional[Buffer]:
         item = self._get_item(obj)
         if item is not None:
             dump = self._tx.get_dumper(item, self._adapt_format).dump
diff --git a/psycopg/psycopg/types/net.py b/psycopg/psycopg/types/net.py
index 76522dcbb..b8fc99204 100644
--- a/psycopg/psycopg/types/net.py
+++ b/psycopg/psycopg/types/net.py
@@ -52,14 +52,14 @@ class _LazyIpaddress:
 class InterfaceDumper(Dumper):
     oid = _oids.INET_OID
 
-    def dump(self, obj: Interface) -> bytes:
+    def dump(self, obj: Interface) -> Optional[Buffer]:
         return str(obj).encode()
 
 
 class NetworkDumper(Dumper):
     oid = _oids.CIDR_OID
 
-    def dump(self, obj: Network) -> bytes:
+    def dump(self, obj: Network) -> Optional[Buffer]:
         return str(obj).encode()
 
 
@@ -69,7 +69,7 @@ class _AIBinaryDumper(Dumper):
 
 
 class AddressBinaryDumper(_AIBinaryDumper):
-    def dump(self, obj: Address) -> bytes:
+    def dump(self, obj: Address) -> Optional[Buffer]:
         packed = obj.packed
         family = PGSQL_AF_INET if obj.version == 4 else PGSQL_AF_INET6
         head = bytes((family, obj.max_prefixlen, 0, len(packed)))
@@ -77,7 +77,7 @@ class AddressBinaryDumper(_AIBinaryDumper):
 
 
 class InterfaceBinaryDumper(_AIBinaryDumper):
-    def dump(self, obj: Interface) -> bytes:
+    def dump(self, obj: Interface) -> Optional[Buffer]:
         packed = obj.packed
         family = PGSQL_AF_INET if obj.version == 4 else PGSQL_AF_INET6
         head = bytes((family, obj.network.prefixlen, 0, len(packed)))
@@ -94,7 +94,7 @@ class InetBinaryDumper(_AIBinaryDumper, _LazyIpaddress):
         super().__init__(cls, context)
         self._ensure_module()
 
-    def dump(self, obj: Union[Address, Interface]) -> bytes:
+    def dump(self, obj: Union[Address, Interface]) -> Optional[Buffer]:
         packed = obj.packed
         family = PGSQL_AF_INET if obj.version == 4 else PGSQL_AF_INET6
         if isinstance(obj, (IPv4Interface, IPv6Interface)):
@@ -110,7 +110,7 @@ class NetworkBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.CIDR_OID
 
-    def dump(self, obj: Network) -> bytes:
+    def dump(self, obj: Network) -> Optional[Buffer]:
         packed = obj.network_address.packed
         family = PGSQL_AF_INET if obj.version == 4 else PGSQL_AF_INET6
         head = bytes((family, obj.prefixlen, 1, len(packed)))
diff --git a/psycopg/psycopg/types/none.py b/psycopg/psycopg/types/none.py
index 2ab857cca..b65f6315b 100644
--- a/psycopg/psycopg/types/none.py
+++ b/psycopg/psycopg/types/none.py
@@ -4,7 +4,9 @@ Adapters for None.
 
 # Copyright (C) 2020 The Psycopg Team
 
-from ..abc import AdaptContext, NoneType
+from typing import Optional
+
+from ..abc import AdaptContext, NoneType, Buffer
 from ..adapt import Dumper
 
 
@@ -14,10 +16,10 @@ class NoneDumper(Dumper):
     quote(), so it can be used in sql composition.
     """
 
-    def dump(self, obj: None) -> bytes:
+    def dump(self, obj: None) -> Optional[Buffer]:
         raise NotImplementedError("NULL is passed to Postgres in other ways")
 
-    def quote(self, obj: None) -> bytes:
+    def quote(self, obj: None) -> Buffer:
         return b"NULL"
 
 
diff --git a/psycopg/psycopg/types/numeric.py b/psycopg/psycopg/types/numeric.py
index 1817740fd..4bfef8e2f 100644
--- a/psycopg/psycopg/types/numeric.py
+++ b/psycopg/psycopg/types/numeric.py
@@ -38,16 +38,18 @@ if TYPE_CHECKING:
 
 
 class _IntDumper(Dumper):
-    def dump(self, obj: Any) -> Buffer:
+    def dump(self, obj: Any) -> Optional[Buffer]:
         return str(obj).encode()
 
     def quote(self, obj: Any) -> Buffer:
         value = self.dump(obj)
+        if value is None:
+            return b"NULL"
         return value if obj >= 0 else b" " + value
 
 
 class _IntOrSubclassDumper(_IntDumper):
-    def dump(self, obj: Any) -> Buffer:
+    def dump(self, obj: Any) -> Optional[Buffer]:
         t = type(obj)
         # Convert to int in order to dump IntEnum or numpy.integer correctly
         if t is not int:
@@ -59,12 +61,16 @@ class _IntOrSubclassDumper(_IntDumper):
 class _SpecialValuesDumper(Dumper):
     _special: Dict[bytes, bytes] = {}
 
-    def dump(self, obj: Any) -> bytes:
+    def dump(self, obj: Any) -> Optional[Buffer]:
         return str(obj).encode()
 
-    def quote(self, obj: Any) -> bytes:
+    def quote(self, obj: Any) -> Buffer:
         value = self.dump(obj)
 
+        if value is None:
+            return b"NULL"
+        if not isinstance(value, bytes):
+            value = bytes(value)
         if value in self._special:
             return self._special[value]
 
@@ -89,21 +95,21 @@ class FloatBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.FLOAT8_OID
 
-    def dump(self, obj: float) -> bytes:
+    def dump(self, obj: float) -> Optional[Buffer]:
         return pack_float8(obj)
 
 
 class Float4BinaryDumper(FloatBinaryDumper):
     oid = _oids.FLOAT4_OID
 
-    def dump(self, obj: float) -> bytes:
+    def dump(self, obj: float) -> Optional[Buffer]:
         return pack_float4(obj)
 
 
 class DecimalDumper(_SpecialValuesDumper):
     oid = _oids.NUMERIC_OID
 
-    def dump(self, obj: Decimal) -> bytes:
+    def dump(self, obj: Decimal) -> Optional[Buffer]:
         return dump_decimal_to_text(obj)
 
     _special = {
@@ -134,7 +140,7 @@ class OidDumper(_IntOrSubclassDumper):
 
 
 class IntDumper(Dumper):
-    def dump(self, obj: Any) -> bytes:
+    def dump(self, obj: Any) -> Optional[Buffer]:
         raise TypeError(
             f"{type(self).__name__} is a dispatcher to other dumpers:"
             " dump() is not supposed to be called"
@@ -164,21 +170,21 @@ class IntDumper(Dumper):
 class Int2BinaryDumper(Int2Dumper):
     format = Format.BINARY
 
-    def dump(self, obj: int) -> bytes:
+    def dump(self, obj: int) -> Optional[Buffer]:
         return pack_int2(obj)
 
 
 class Int4BinaryDumper(Int4Dumper):
     format = Format.BINARY
 
-    def dump(self, obj: int) -> bytes:
+    def dump(self, obj: int) -> Optional[Buffer]:
         return pack_int4(obj)
 
 
 class Int8BinaryDumper(Int8Dumper):
     format = Format.BINARY
 
-    def dump(self, obj: int) -> bytes:
+    def dump(self, obj: int) -> Optional[Buffer]:
         return pack_int8(obj)
 
 
@@ -190,14 +196,14 @@ BIT_PER_PGDIGIT = log(2) / log(10_000)
 class IntNumericBinaryDumper(IntNumericDumper):
     format = Format.BINARY
 
-    def dump(self, obj: int) -> Buffer:
+    def dump(self, obj: int) -> Optional[Buffer]:
         return dump_int_to_numeric_binary(obj)
 
 
 class OidBinaryDumper(OidDumper):
     format = Format.BINARY
 
-    def dump(self, obj: int) -> bytes:
+    def dump(self, obj: int) -> Optional[Buffer]:
         return pack_uint4(obj)
 
 
@@ -350,7 +356,7 @@ class DecimalBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.NUMERIC_OID
 
-    def dump(self, obj: Decimal) -> Buffer:
+    def dump(self, obj: Decimal) -> Optional[Buffer]:
         return dump_decimal_to_numeric_binary(obj)
 
 
@@ -379,11 +385,13 @@ class _MixedNumericDumper(Dumper, ABC):
                 _MixedNumericDumper.int_classes = int
 
     @abstractmethod
-    def dump(self, obj: Union[Decimal, int, "numpy.integer[Any]"]) -> Buffer: ...
+    def dump(
+        self, obj: Union[Decimal, int, "numpy.integer[Any]"]
+    ) -> Optional[Buffer]: ...
 
 
 class NumericDumper(_MixedNumericDumper):
-    def dump(self, obj: Union[Decimal, int, "numpy.integer[Any]"]) -> Buffer:
+    def dump(self, obj: Union[Decimal, int, "numpy.integer[Any]"]) -> Optional[Buffer]:
         if isinstance(obj, self.int_classes):
             return str(obj).encode()
         elif isinstance(obj, Decimal):
@@ -397,7 +405,7 @@ class NumericDumper(_MixedNumericDumper):
 class NumericBinaryDumper(_MixedNumericDumper):
     format = Format.BINARY
 
-    def dump(self, obj: Union[Decimal, int, "numpy.integer[Any]"]) -> Buffer:
+    def dump(self, obj: Union[Decimal, int, "numpy.integer[Any]"]) -> Optional[Buffer]:
         if type(obj) is int:
             return dump_int_to_numeric_binary(obj)
         elif isinstance(obj, Decimal):
diff --git a/psycopg/psycopg/types/range.py b/psycopg/psycopg/types/range.py
index e320e4203..c3d472621 100644
--- a/psycopg/psycopg/types/range.py
+++ b/psycopg/psycopg/types/range.py
@@ -354,7 +354,7 @@ class RangeDumper(BaseRangeDumper):
     The dumper can upgrade to one specific for a different range type.
     """
 
-    def dump(self, obj: Range[Any]) -> Buffer:
+    def dump(self, obj: Range[Any]) -> Optional[Buffer]:
         item = self._get_item(obj)
         if item is not None:
             dump = self._tx.get_dumper(item, self._adapt_format).dump
@@ -399,7 +399,7 @@ _re_esc = re.compile(rb"([\\\"])")
 class RangeBinaryDumper(BaseRangeDumper):
     format = Format.BINARY
 
-    def dump(self, obj: Range[Any]) -> Buffer:
+    def dump(self, obj: Range[Any]) -> Optional[Buffer]:
         item = self._get_item(obj)
         if item is not None:
             dump = self._tx.get_dumper(item, self._adapt_format).dump
diff --git a/psycopg/psycopg/types/shapely.py b/psycopg/psycopg/types/shapely.py
index e9387007a..571445413 100644
--- a/psycopg/psycopg/types/shapely.py
+++ b/psycopg/psycopg/types/shapely.py
@@ -43,12 +43,12 @@ class GeometryLoader(Loader):
 class BaseGeometryBinaryDumper(Dumper):
     format = Format.BINARY
 
-    def dump(self, obj: "BaseGeometry") -> bytes:
+    def dump(self, obj: "BaseGeometry") -> Optional[Buffer]:
         return dumps(obj)  # type: ignore
 
 
 class BaseGeometryDumper(Dumper):
-    def dump(self, obj: "BaseGeometry") -> bytes:
+    def dump(self, obj: "BaseGeometry") -> Optional[Buffer]:
         return dumps(obj, hex=True).encode()  # type: ignore
 
 
diff --git a/psycopg/psycopg/types/string.py b/psycopg/psycopg/types/string.py
index a0adc5650..88548180a 100644
--- a/psycopg/psycopg/types/string.py
+++ b/psycopg/psycopg/types/string.py
@@ -33,7 +33,7 @@ class _StrBinaryDumper(_BaseStrDumper):
 
     format = Format.BINARY
 
-    def dump(self, obj: str) -> bytes:
+    def dump(self, obj: str) -> Optional[Buffer]:
         # the server will raise DataError subclass if the string contains 0x00
         return obj.encode(self._encoding)
 
@@ -45,7 +45,7 @@ class _StrDumper(_BaseStrDumper):
     Subclasses shall specify the oids of real types (text, varchar, name...).
     """
 
-    def dump(self, obj: str) -> bytes:
+    def dump(self, obj: str) -> Optional[Buffer]:
         if "\x00" in obj:
             raise DataError("PostgreSQL text fields cannot contain NUL (0x00) bytes")
         else:
@@ -132,11 +132,13 @@ class BytesDumper(Dumper):
         super().__init__(cls, context)
         self._esc = Escaping(self.connection.pgconn if self.connection else None)
 
-    def dump(self, obj: Buffer) -> Buffer:
+    def dump(self, obj: Buffer) -> Optional[Buffer]:
         return self._esc.escape_bytea(obj)
 
-    def quote(self, obj: Buffer) -> bytes:
+    def quote(self, obj: Buffer) -> Buffer:
         escaped = self.dump(obj)
+        if escaped is None:
+            return b"NULL"
 
         # We cannot use the base quoting because escape_bytea already returns
         # the quotes content. if scs is off it will escape the backslashes in
@@ -165,7 +167,7 @@ class BytesBinaryDumper(Dumper):
     format = Format.BINARY
     oid = _oids.BYTEA_OID
 
-    def dump(self, obj: Buffer) -> Buffer:
+    def dump(self, obj: Buffer) -> Optional[Buffer]:
         return obj
 
 
diff --git a/psycopg/psycopg/types/uuid.py b/psycopg/psycopg/types/uuid.py
index 6e0d8156b..df4509ee5 100644
--- a/psycopg/psycopg/types/uuid.py
+++ b/psycopg/psycopg/types/uuid.py
@@ -21,14 +21,14 @@ UUID: Callable[..., "uuid.UUID"] = None  # type: ignore[assignment]
 class UUIDDumper(Dumper):
     oid = _oids.UUID_OID
 
-    def dump(self, obj: "uuid.UUID") -> bytes:
+    def dump(self, obj: "uuid.UUID") -> Optional[Buffer]:
         return obj.hex.encode()
 
 
 class UUIDBinaryDumper(UUIDDumper):
     format = Format.BINARY
 
-    def dump(self, obj: "uuid.UUID") -> bytes:
+    def dump(self, obj: "uuid.UUID") -> Optional[Buffer]:
         return obj.bytes
 
 
diff --git a/psycopg_c/psycopg_c/_psycopg/adapt.pyx b/psycopg_c/psycopg_c/_psycopg/adapt.pyx
index cfd90741a..e32ef19d1 100644
--- a/psycopg_c/psycopg_c/_psycopg/adapt.pyx
+++ b/psycopg_c/psycopg_c/_psycopg/adapt.pyx
@@ -58,14 +58,14 @@ cdef class CDumper:
         """
         raise NotImplementedError()
 
-    def dump(self, obj):
+    def dump(self, obj) -> Optional[Buffer]:
         """Return the Postgres representation of *obj* as Python array of bytes"""
         cdef rv = PyByteArray_FromStringAndSize("", 0)
         cdef Py_ssize_t length = self.cdump(obj, rv, 0)
         PyByteArray_Resize(rv, length)
         return rv
 
-    def quote(self, obj):
+    def quote(self, obj) -> Buffer:
         cdef char *ptr
         cdef char *ptr_out
         cdef Py_ssize_t length
diff --git a/psycopg_c/psycopg_c/types/bool.pyx b/psycopg_c/psycopg_c/types/bool.pyx
index 86cf88e94..5b3a7c387 100644
--- a/psycopg_c/psycopg_c/types/bool.pyx
+++ b/psycopg_c/psycopg_c/types/bool.pyx
@@ -28,7 +28,7 @@ cdef class BoolDumper(CDumper):
 
         return 1
 
-    def quote(self, obj: bool) -> bytes:
+    def quote(self, obj: bool) -> Optional[Buffer]:
         if obj is True:
             return b"true"
         elif obj is False:
diff --git a/psycopg_c/psycopg_c/types/numeric.pyx b/psycopg_c/psycopg_c/types/numeric.pyx
index f9580fd84..f2f2c2ac1 100644
--- a/psycopg_c/psycopg_c/types/numeric.pyx
+++ b/psycopg_c/psycopg_c/types/numeric.pyx
@@ -55,7 +55,7 @@ cdef class _IntDumper(CDumper):
     cdef Py_ssize_t cdump(self, obj, bytearray rv, Py_ssize_t offset) except -1:
         return dump_int_to_text(obj, rv, offset)
 
-    def quote(self, obj) -> bytearray:
+    def quote(self, obj) -> Optional[Buffer]:
         cdef Py_ssize_t length
 
         rv = PyByteArray_FromStringAndSize("", 0)
@@ -311,7 +311,7 @@ cdef class _FloatDumper(CDumper):
         PyMem_Free(out)
         return length
 
-    def quote(self, obj) -> bytes:
+    def quote(self, obj) -> Optional[Buffer]:
         value = bytes(self.dump(obj))
         cdef PyObject *ptr = PyDict_GetItem(_special_float, value)
         if ptr != NULL:
@@ -417,7 +417,7 @@ cdef class DecimalDumper(CDumper):
     cdef Py_ssize_t cdump(self, obj, bytearray rv, Py_ssize_t offset) except -1:
         return dump_decimal_to_text(obj, rv, offset)
 
-    def quote(self, obj) -> bytes:
+    def quote(self, obj) -> Optional[Buffer]:
         value = bytes(self.dump(obj))
         cdef PyObject *ptr = PyDict_GetItem(_special_decimal, value)
         if ptr != NULL:
diff --git a/psycopg_c/psycopg_c/types/string.pyx b/psycopg_c/psycopg_c/types/string.pyx
index da18b015a..170b17b7d 100644
--- a/psycopg_c/psycopg_c/types/string.pyx
+++ b/psycopg_c/psycopg_c/types/string.pyx
@@ -215,7 +215,7 @@ cdef class BytesDumper(CDumper):
         libpq.PQfreemem(out)
         return len_out
 
-    def quote(self, obj):
+    def quote(self, obj) -> Buffer:
         cdef size_t len_out
         cdef unsigned char *out
         cdef char *ptr
diff --git a/tests/test_copy.py b/tests/test_copy.py
index 596b837f1..286e6e440 100644
--- a/tests/test_copy.py
+++ b/tests/test_copy.py
@@ -308,7 +308,9 @@ def test_subclass_adapter(conn, format):
     class MyStrDumper(BaseDumper):
 
         def dump(self, obj):
-            return super().dump(obj) * 2
+            rv = super().dump(obj)
+            assert rv
+            return bytes(rv) * 2
 
     conn.adapters.register_dumper(str, MyStrDumper)
 
diff --git a/tests/test_copy_async.py b/tests/test_copy_async.py
index 6d1d49566..b06e880ae 100644
--- a/tests/test_copy_async.py
+++ b/tests/test_copy_async.py
@@ -317,7 +317,9 @@ async def test_subclass_adapter(aconn, format):
 
     class MyStrDumper(BaseDumper):
         def dump(self, obj):
-            return super().dump(obj) * 2
+            rv = super().dump(obj)
+            assert rv
+            return bytes(rv) * 2
 
     aconn.adapters.register_dumper(str, MyStrDumper)