proto3-suite-0.9.4: src/Proto3/Suite/JSONPB/Class.hs
{-# LANGUAGE CPP #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DerivingVia #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE ViewPatterns #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
-- | Support for the "JSONPB" canonical JSON encoding described at
-- <https://developers.google.com/protocol-buffers/docs/proto3#json>.
--
-- This modules provides 'Data.Aeson'-like helper functions, typeclasses, and
-- instances for converting to and from values of types which have a JSONPB
-- representation and equivalent underlying 'Data.Aeson' representations.
--
-- This module also presents a (very minimal) surface syntax for Aeson-like
-- operations; the idea is that we can write 'ToJSONPB' and 'FromJSONPB'
-- instances in a very similar manner to 'A.ToJSON' and 'A.FromJSON' instances,
-- except that doing so specifies JSONPB codecs instead of vanilla JSON codecs.
--
-- Example use:
--
-- @
-- message Scalar32 {
-- int32 i32 = 1;
-- uint32 u32 = 2;
-- sint32 s32 = 3;
-- fixed32 f32 = 4;
-- sfixed32 sf32 = 5;
-- }
--
-- instance ToJSONPB Scalar32 where
-- toJSONPB (Scalar32 i32 u32 s32 f32 sf32) = object
-- [ "i32" .= i32
-- , "u32" .= u32
-- , "s32" .= s32
-- , "f32" .= f32
-- , "sf32" .= sf32
-- ]
-- toEncodingPB (Scalar32 i32 u32 s32 f32 sf32) = pairs
-- [ "i32" .= i32
-- , "u32" .= u32
-- , "s32" .= s32
-- , "f32" .= f32
-- , "sf32" .= sf32
-- ]
--
-- instance FromJSONPB Scalar32 where
-- parseJSONPB = withObject "Scalar32" $ \obj ->
-- pure Scalar32
-- <*> obj .: "i32"
-- <*> obj .: "u32"
-- <*> obj .: "s32"
-- <*> obj .: "f32"
-- <*> obj .: "sf32"
-- @
module Proto3.Suite.JSONPB.Class where
import qualified Data.Aeson as A (Encoding, FromJSON (..),
FromJSONKey (..),
FromJSONKeyFunction (..),
ToJSON (..), Value (..),
ToJSON1(..), FromJSON1(..),
ToJSONKey(..),
decode, eitherDecode,
(.!=))
import qualified Data.Aeson.Encoding as E
import qualified Data.Aeson.Encoding.Internal as E
#if !MIN_VERSION_aeson(2,1,0)
import qualified Data.Aeson.Internal as A (formatError, iparse)
#endif
#if MIN_VERSION_aeson(2,0,0)
import qualified Data.Aeson.Key as A
#endif
import qualified Data.Aeson.Parser as A (eitherDecodeWith, json)
import qualified Data.Aeson.Types as A (Object, Pair, Parser,
Series,
explicitParseField,
explicitParseFieldMaybe,
#if MIN_VERSION_aeson(2,1,0)
formatError,
iparse,
#endif
object,
#if !(MIN_VERSION_aeson(2,0,2))
toJSONKeyText,
#endif
typeMismatch,)
import qualified Data.Attoparsec.ByteString as Atto (skipWhile)
import qualified Data.Attoparsec.ByteString.Char8 as Atto (Parser, endOfInput)
import qualified Data.Binary.Builder as Builder
import qualified Data.ByteString as BS
import qualified Data.ByteString.Base64 as B64
import qualified Data.ByteString.Lazy as LBS
import Data.Maybe
import qualified Data.Map as M
import Data.Text (Text)
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.Encoding as TL
import qualified Data.Text.Short as TS
import qualified Data.Vector as V
import GHC.Exts (Proxy#, proxy#)
import GHC.Generics (Generic)
import GHC.Int (Int32, Int64)
import GHC.Word (Word32, Word64)
import Google.Protobuf.Wrappers.Polymorphic (Wrapped(..))
import Proto3.Suite.Class (HasDefault (def, isDefault),
Named (nameOf))
import Proto3.Suite.Types (Enumerated(..), Fixed(..),
ForceEmit(..), Nested(..),
NestedVec(..), PackedVec(..),
Signed(..), UnpackedVec(..))
import qualified Proto3.Suite.Types
import Proto3.Wire.Class (ProtoEnum(..))
import Test.QuickCheck.Arbitrary (Arbitrary(..))
#if MIN_VERSION_aeson(2,0,0)
type Key = A.Key
keyFromText :: Text -> Key
keyFromText = A.fromText
#else
type Key = Text
keyFromText :: Text -> Text
keyFromText = id
#endif
-- * Typeclass definitions
-- | 'A.ToJSON' variant for JSONPB direct encoding via 'A.Encoding'
class ToJSONPB a where
-- | 'A.toJSON' variant for JSONPB encoders.
toJSONPB :: a -> Options -> A.Value
-- | 'A.toEncoding' variant for JSONPB encoders. If an implementation is not
-- provided, uses 'toJSONPB' (which is less efficient since it indirects
-- through the 'A.Value' IR).
toEncodingPB :: a -> Options -> A.Encoding
toEncodingPB x = A.toEncoding . toJSONPB x
instance ToJSONPB A.Value where
toJSONPB v _ = v
toEncodingPB v _ = E.value v
instance ToJSONPB A.Encoding where
toJSONPB e _ = fromMaybe A.Null . A.decode . Builder.toLazyByteString . E.fromEncoding $ e
toEncodingPB e _ = e
-- | 'A.FromJSON' variant for JSONPB decoding from the 'A.Value' IR
class FromJSONPB a where
-- | 'A.parseJSON' variant for JSONPB decoders.
parseJSONPB :: A.Value -> A.Parser a
instance FromJSONPB A.Value where
parseJSONPB = pure
-- | JSONPB format shortcuts Google wrappers types.
deriving newtype instance FromJSONPB a => FromJSONPB (Wrapped a)
-- | JSONPB format shortcuts Google wrappers types.
deriving newtype instance ToJSONPB a => ToJSONPB (Wrapped a)
-- * JSONPB codec entry points
-- | 'Data.Aeson.encode' variant for serializing a JSONPB value as a lazy
-- 'LBS.ByteString'.
encode :: ToJSONPB a => Options -> a -> LBS.ByteString
encode opts x = E.encodingToLazyByteString (toEncodingPB x opts)
{-# INLINE encode #-}
-- | 'Data.Aeson.eitherDecode' variant for deserializing a JSONPB value from a
-- lazy 'LBS.ByteString'.
eitherDecode :: FromJSONPB a => LBS.ByteString -> Either String a
eitherDecode = eitherFormatError . A.eitherDecodeWith jsonEOF (A.iparse parseJSONPB)
where
eitherFormatError = either (Left . uncurry A.formatError) Right
{-# INLINE eitherFormatError #-}
-- NB: cribbed from aeson-1.1.1.0:Data.Aeson.Parser.Internal.jsonEOF, which
-- is not exported. It's simple, so we just inline it here. Might be worth
-- submitting a PR to export this.
jsonEOF :: Atto.Parser A.Value
jsonEOF = A.json <* skipSpace <* Atto.endOfInput
where
skipSpace :: Atto.Parser ()
skipSpace = Atto.skipWhile $ \w -> w == 0x20 || w == 0x0a || w == 0x0d || w == 0x09
{-# INLINE skipSpace #-}
{-# INLINE eitherDecode #-}
-- * Operator definitions
-- | JSONPB-encoded monoidal key-value pairs
class Monoid m => KeyValuePB m where
pair :: ToJSONPB v => Text -> v -> Options -> m
instance KeyValuePB A.Series where pair k v opts = E.pair (keyFromText k) (toEncodingPB v opts)
instance KeyValuePB [A.Pair] where pair k v opts = pure (keyFromText k, toJSONPB v opts)
-- | Construct a monoidal key-value pair, using 'mempty' to represent omission
-- of default values (unless the given 'Options' force their emission).
(.=) :: (HasDefault v, ToJSONPB v, KeyValuePB kvp) => Text -> v -> Options -> kvp
k .= v = mk
where
mk opts@Options{..}
| not optEmitDefaultValuedFields && isDefault v
= mempty
| otherwise
= pair k v opts
-- | 'Data.Aeson..:' variant for JSONPB; if the given key is missing from the
-- object, or if it is present but its value is null, we produce the default
-- protobuf value for the field type
(.:) :: (FromJSONPB a, HasDefault a) => A.Object -> Text -> A.Parser a
obj .: key = obj .:? keyFromText key A..!= def
where
(.:?) = A.explicitParseFieldMaybe parseJSONPB
parseField :: FromJSONPB a
=> A.Object -> Key -> A.Parser a
parseField = A.explicitParseField parseJSONPB
-- | >>> isDefault (def :: E.Encoding)
-- True
instance HasDefault E.Encoding where
def = E.empty
isDefault = E.nullEncoding
-- | >>> isDefault (def :: A.Value)
-- True
instance HasDefault A.Value where
def = A.Null
isDefault = (== A.Null)
-- * JSONPB rendering and parsing options
data Options = Options
{ optEmitDefaultValuedFields :: Bool
, optEmitNamedOneof :: Bool
-- ^ For compatibility with the Go, C++, and Python JSONPB implementations.
--
-- If 'False', the following message
--
-- > message MyMessage {
-- > oneof animal {
-- > Cat cat = 1;
-- > Dog dog = 2;
-- > }
-- > }
--
-- will be serialized as
--
-- > MyMessage (Animal (Cat "Simba")) => { "cat": "Simba" }
--
-- instead of
--
-- > MyMessage (Animal (Cat "Simba")) => { "animal": { "cat": "Simba" } }
--
} deriving (Eq, Generic, Show)
instance Arbitrary Options where
arbitrary = Options <$> arbitrary <*> arbitrary
-- | Default options for JSON encoding. By default, all options are @True@.
defaultOptions :: Options
defaultOptions = Options
{ optEmitDefaultValuedFields = True
, optEmitNamedOneof = True
}
-- | Options for JSONPB encoding.
jsonPBOptions :: Options
jsonPBOptions = Options
{ optEmitDefaultValuedFields = False
, optEmitNamedOneof = False
}
-- * Helper types and functions
dropNamedPrefix :: Named a => Proxy# a -> String -> String
dropNamedPrefix p = drop (length (nameOf p :: String))
object :: [Options -> [A.Pair]] -> Options -> A.Value
object fs = A.object . mconcat fs
-- | As 'object', but produces 'A.Null' when there are no pairs to wrap (cf. the
-- empty object result of 'object)
--
-- >>> object [const []] defaultOptions
-- Object (fromList [])
-- >>> objectOrNull [const []] defaultOptions
-- Null
objectOrNull :: [Options -> [A.Pair]] -> Options -> A.Value
objectOrNull fs options = case mconcat fs options of
[] -> A.Null
nonEmpty -> A.object nonEmpty
pairs :: [Options -> A.Series] -> Options -> E.Encoding
pairs fs = E.pairs . mconcat fs
-- | As 'pairs', but produces the "null" when there is no series to encode
-- (cf. the empty object encoding of 'pairs')
--
-- >>> pairs [const mempty] defaultOptions
-- "{}"
-- >>> pairsOrNull [const mempty] defaultOptions
-- "null"
pairsOrNull :: [Options -> A.Series] -> Options -> E.Encoding
pairsOrNull fs options = case mconcat fs options of
E.Empty -> E.null_
nonEmpty -> E.pairs nonEmpty
enumFieldString :: forall a. (Named a, Show a) => a -> A.Value
enumFieldString = A.String . T.pack . dropNamedPrefix (proxy# :: Proxy# a) . show
enumFieldEncoding :: forall a. (Named a, Show a) => a -> A.Encoding
enumFieldEncoding = E.string . dropNamedPrefix (proxy# :: Proxy# a) . show
-- | A 'Data.Aeson' 'A.Value' encoder for values which can be
-- JSONPB-encoded.
toAesonValue :: ToJSONPB a => a -> A.Value
toAesonValue = flip toJSONPB defaultOptions
-- | A direct 'A.Encoding' for values which can be JSONPB-encoded.
toAesonEncoding :: ToJSONPB a => a -> A.Encoding
toAesonEncoding = flip toEncodingPB defaultOptions
-- | Parse a JSONPB floating point value; first parameter provides context for
-- type mismatches
parseFP :: (A.FromJSON a, A.FromJSONKey a) => String -> A.Value -> A.Parser a
parseFP tyDesc v = case v of
A.Number{} -> A.parseJSON v
A.String t -> case A.fromJSONKey of
A.FromJSONKeyTextParser p
-> p t
_ -> fail "internal: parseKeyPB: unexpected FromJSONKey summand"
_ -> A.typeMismatch tyDesc v
-- | Liberally parse an integer value (e.g. 42 or "42" as 42); first parameter
-- provides context for type mismatches
parseNumOrDecimalString :: (A.FromJSON a) => String -> A.Value -> A.Parser a
parseNumOrDecimalString tyDesc v = case v of
A.Number{} -> A.parseJSON v
A.String t -> either fail pure . A.eitherDecode . TL.encodeUtf8 . TL.fromStrict $ t
_ -> A.typeMismatch tyDesc v
-- * Common instances for jsonpb codec implementations
-- ** Instances for scalar types
--------------------------------------------------------------------------------
-- Boolean scalar type
instance ToJSONPB Bool where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB Bool where
parseJSONPB = A.parseJSON
--------------------------------------------------------------------------------
-- Integer scalar types
--
-- * 32 bit integer values render to JSON decimal numbers; either numbers or
-- strings are accepted.
--
-- * 64 bit integer values render to JSON decimal strings; either numbers
-- or strings are accepted.
--
-- int32 / sint32 / sfixed32
instance ToJSONPB Int32 where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB Int32 where
parseJSONPB = parseNumOrDecimalString "int32 / sint32"
-- uint32 / fixed32
instance ToJSONPB Word32 where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB Word32 where
parseJSONPB = parseNumOrDecimalString "uint32"
-- int64 / sint64 / sfixed64
instance ToJSONPB Int64 where
toJSONPB x _ = A.String . T.pack . show $ x
toEncodingPB x _ = E.string (show x)
instance FromJSONPB Int64 where
parseJSONPB = parseNumOrDecimalString "int64 / sint64"
-- unit64 / fixed64
instance ToJSONPB Word64 where
toJSONPB x _ = A.String . T.pack . show $ x
toEncodingPB x _ = E.string (show x)
instance FromJSONPB Word64 where
parseJSONPB = parseNumOrDecimalString "int64 / sint64"
-- Distinctions between varint and fixed-width formats do not matter to JSONPB.
deriving newtype instance FromJSONPB a => FromJSONPB (Fixed a)
deriving newtype instance ToJSONPB a => ToJSONPB (Fixed a)
-- Zig-zag encoding issues do not matter to JSONPB.
deriving newtype instance FromJSONPB a => FromJSONPB (Signed a)
deriving newtype instance ToJSONPB a => ToJSONPB (Signed a)
--------------------------------------------------------------------------------
-- Floating point scalar types
--
-- JSON value will be a number or one of the special string values "NaN",
-- "Infinity", and "-Infinity". Either numbers or strings are accepted. Exponent
-- notation is also accepted.
-- float
instance ToJSONPB Float where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB Float where
parseJSONPB = parseFP "float"
-- double
instance ToJSONPB Double where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB Double where
parseJSONPB = parseFP "double"
--------------------------------------------------------------------------------
-- Stringly types (string and bytes)
-- string
instance ToJSONPB T.Text where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB T.Text where
parseJSONPB = A.parseJSON
instance ToJSONPB TL.Text where
toJSONPB = const . A.toJSON
toEncodingPB = const . A.toEncoding
instance FromJSONPB TL.Text where
parseJSONPB = A.parseJSON
instance ToJSONPB TS.ShortText where
toJSONPB = toJSONPB . TS.toText
toEncodingPB = toEncodingPB . TS.toText
instance FromJSONPB TS.ShortText where
parseJSONPB = fmap TS.fromText . A.parseJSON
deriving newtype instance ToJSONPB a => ToJSONPB (Proto3.Suite.Types.String a)
deriving newtype instance FromJSONPB a => FromJSONPB (Proto3.Suite.Types.String a)
-- bytes
bsToJSONPB :: BS.ByteString -> A.Value
bsToJSONPB (T.decodeUtf8' . B64.encode -> ebs) = case ebs of
Right bs -> A.toJSON bs
Left e -> error ("internal: failed to encode B64-encoded bytestring: " ++ show e)
-- NB: T.decodeUtf8' should never fail because we B64-encode the
-- incoming bytestring.
instance ToJSONPB BS.ByteString where
toJSONPB bs _ = bsToJSONPB bs
toEncodingPB bs opts = E.value (toJSONPB bs opts)
instance FromJSONPB BS.ByteString where
parseJSONPB (A.String b64enc) = pure . B64.decodeLenient . T.encodeUtf8 $ b64enc
parseJSONPB v = A.typeMismatch "bytes" v
deriving newtype instance ToJSONPB a => ToJSONPB (Proto3.Suite.Types.Bytes a)
deriving newtype instance FromJSONPB a => FromJSONPB (Proto3.Suite.Types.Bytes a)
--------------------------------------------------------------------------------
-- Enumerated types
enumToJSONPB :: (e -> Options -> a) -- ^ JSONPB encoder function to use
-> (Int32 -> a) -- ^ handles out-of-range enums
-> Enumerated e -- ^ the enumerated value to encode
-> Options -- ^ JSONPB encoding options
-> a -- ^ the JSONPB-encoded value
enumToJSONPB enc outOfRange (Enumerated e) opts =
either outOfRange (\input -> enc input opts) e
-- | If you ask for an unrecognized enumerator code to be emitted, then this
-- instance will emit it numerically, relying upon parser behavior required by:
-- <https://developers.google.com/protocol-buffers/docs/proto3#json>
instance ToJSONPB e => ToJSONPB (Enumerated e) where
toJSONPB = enumToJSONPB toJSONPB (A.Number . fromIntegral)
toEncodingPB = enumToJSONPB toEncodingPB E.int32
-- | Supports both names and integer codes, as required by:
-- <https://developers.google.com/protocol-buffers/docs/proto3#json>
instance (ProtoEnum e, FromJSONPB e) => FromJSONPB (Enumerated e) where
-- In order to reduce the amount of generated Haskell code we delegate to
-- such code only in the String case, and when converting 'Int32' to @e@.
-- The rest of the parser we implement here, generically.
parseJSONPB A.Null = pure def
parseJSONPB (A.String s) = Enumerated . Right <$> parseJSONPB (A.String s)
parseJSONPB (A.Number n) = fromCode <$> parseJSONPB (A.Number n)
where
fromCode c = Enumerated $ maybe (Left c) Right (toProtoEnumMay c)
parseJSONPB v = fail $ "Expected enumerator name or code, not: " ++ show v
-- ** Instances for composite types
--------------------------------------------------------------------------------
-- Instances for repeated messages
--
-- JSON value will be the vector elements encoded as a JSON array. The null
-- value is accepted as the empty list, @[]@.
instance ToJSONPB a => ToJSONPB (V.Vector a) where
toJSONPB v opts = A.Array (V.map (\x -> toJSONPB x opts) v)
toEncodingPB v opts = E.list (\x -> toEncodingPB x opts) (V.toList v)
instance FromJSONPB a => FromJSONPB (V.Vector a) where
parseJSONPB (A.Array vs) = mapM parseJSONPB vs
parseJSONPB A.Null = pure []
parseJSONPB v = A.typeMismatch "repeated" v
-- Packed/unpacked distinctions do not matter to JSONPB.
deriving via (V.Vector a) instance FromJSONPB a => FromJSONPB (NestedVec a)
deriving via (V.Vector a) instance ToJSONPB a => ToJSONPB (NestedVec a)
deriving via (V.Vector a) instance FromJSONPB a => FromJSONPB (PackedVec a)
deriving via (V.Vector a) instance ToJSONPB a => ToJSONPB (PackedVec a)
deriving via (V.Vector a) instance FromJSONPB a => FromJSONPB (UnpackedVec a)
deriving via (V.Vector a) instance ToJSONPB a => ToJSONPB (UnpackedVec a)
--------------------------------------------------------------------------------
-- Instances for nested messages
instance ToJSONPB a => ToJSONPB (Maybe a) where
toJSONPB mx opts = maybe A.Null (\x -> toJSONPB x opts) mx
toEncodingPB mx opts = maybe E.null_ (\x -> toEncodingPB x opts) mx
instance FromJSONPB a => FromJSONPB (Maybe a) where
parseJSONPB A.Null = pure Nothing
parseJSONPB v = fmap Just (parseJSONPB v)
deriving via (Maybe a) instance FromJSONPB a => FromJSONPB (Nested a)
deriving via (Maybe a) instance ToJSONPB a => ToJSONPB (Nested a)
--------------------------------------------------------------------------------
-- Instances for optional fields
deriving newtype instance FromJSONPB a => FromJSONPB (ForceEmit a)
deriving newtype instance ToJSONPB a => ToJSONPB (ForceEmit a)
--------------------------------------------------------------------------------
-- Instances for map
deriving newtype instance A.FromJSONKey a => A.FromJSONKey (Fixed a)
deriving newtype instance A.ToJSONKey a => A.ToJSONKey (Fixed a)
deriving newtype instance A.FromJSONKey a => A.FromJSONKey (Signed a)
deriving newtype instance A.ToJSONKey a => A.ToJSONKey (Signed a)
deriving via T.Text instance A.FromJSONKey (Proto3.Suite.Types.String T.Text)
deriving via T.Text instance A.ToJSONKey (Proto3.Suite.Types.String T.Text)
deriving via TL.Text instance A.FromJSONKey (Proto3.Suite.Types.String TL.Text)
deriving via TL.Text instance A.ToJSONKey (Proto3.Suite.Types.String TL.Text)
#if MIN_VERSION_aeson(2,0,2)
deriving via TS.ShortText instance A.FromJSONKey (Proto3.Suite.Types.String TS.ShortText)
deriving via TS.ShortText instance A.ToJSONKey (Proto3.Suite.Types.String TS.ShortText)
#else
instance A.FromJSON (Proto3.Suite.Types.String TS.ShortText) where
parseJSON = fmap (Proto3.Suite.Types.String . TS.fromText) . A.parseJSON
instance A.FromJSONKey (Proto3.Suite.Types.String TS.ShortText) where
fromJSONKey = A.FromJSONKeyText (Proto3.Suite.Types.String . TS.fromText)
instance A.ToJSON (Proto3.Suite.Types.String TS.ShortText) where
toJSON = A.toJSON . TS.toText . Proto3.Suite.Types.string
toEncoding = A.toEncoding . TS.toText . Proto3.Suite.Types.string
instance A.ToJSONKey (Proto3.Suite.Types.String TS.ShortText) where
toJSONKey = A.toJSONKeyText (TS.toText . Proto3.Suite.Types.string)
#endif
instance (A.ToJSONKey k, ToJSONPB k, ToJSONPB v) => ToJSONPB (M.Map k v) where
toJSONPB m opts = A.liftToJSON @(M.Map k)
#if MIN_VERSION_aeson(2,2,0)
(const False) -- Unless and until we test for the protobuf default value.
#endif
(`toJSONPB` opts) (A.Array . V.fromList . map (`toJSONPB` opts)) m
toEncodingPB m opts = A.liftToEncoding @(M.Map k)
#if MIN_VERSION_aeson(2,2,0)
(const False) -- Unless and until we test for the protobuf default value.
#endif
(`toEncodingPB` opts) (E.list (`toEncodingPB` opts)) m
instance (Ord k, A.FromJSONKey k, FromJSONPB k, FromJSONPB v) => FromJSONPB (M.Map k v) where
parseJSONPB = A.liftParseJSON @(M.Map k)
#if MIN_VERSION_aeson(2,2,0)
Nothing -- Unless and until we decide to use the protobuf default value.
#endif
parseJSONPB parseList
where
parseList (A.Array a) = traverse parseJSONPB (V.toList a)
parseList v = A.typeMismatch "not a list" v