Fix generation of negative enum fields (#258)

Fixes an issue where enums with negative field
numbers were compiled to the field's conjugate
in toProtoEnumMay pattern matches.

This commit also adds tests of negative enum codes
based on interoperability with generated Python.

src/Proto3/Suite/DotProto/Generate/Syntax.hs

@@ -959,7 +959,7 @@ intE :: Integral a => a -> HsExp
 intE x = noLocA $ HsOverLit synDef $ mkHsIntegral $ IL
   { il_text = NoSourceText
   , il_neg = x < 0
-  , il_value = abs (toInteger x)
+  , il_value = toInteger x
   }
 
 intP :: Integral a => a -> HsPat
@@ -968,7 +968,7 @@ intP x = noLocA $ NPat synDef overlit Nothing NoExtField
     overlit = L synDef $ mkHsIntegral $ IL
       { il_text = NoSourceText
       , il_neg = x < 0
-      , il_value = abs (toInteger x)
+      , il_value = toInteger x
       }
 
 floatE :: forall f . RealFloat f => f -> HsExp

test-files/test_proto_negative_enum.proto

@@ -0,0 +1,20 @@
+
+syntax="proto3";
+
+package TestProtoNegativeEnum;
+
+enum NegativeEnum {
+  NEGATIVE_ENUM_0 = 0;
+
+  NEGATIVE_ENUM_NEGATIVE_1 = -1;
+
+  NEGATIVE_ENUM_1 = 1;
+
+  NEGATIVE_ENUM_NEGATIVE_128 = -128;
+
+  NEGATIVE_ENUM_128 = 128;
+}
+
+message WithNegativeEnum {
+  NegativeEnum v = 123;
+}

tests/SimpleDecodeDotProto.hs

@@ -28,6 +28,7 @@ import qualified TestProtoImport
 import qualified TestProtoOneof
 import qualified TestProtoOneofImport
 import qualified TestProtoWrappers
+import qualified TestProtoNegativeEnum
 
 data Format = Binary | Jsonpb
   deriving (Bounded, Enum, Eq, Read, Show)
@@ -59,6 +60,7 @@ tests, testCase1, testCase2, testCaseSignedInts, testCase3, testCase4,
     testCase_DoubleValue, testCase_FloatValue, testCase_Int64Value,
     testCase_UInt64Value, testCase_Int32Value, testCase_UInt32Value,
     testCase_BoolValue, testCase_StringValue, testCase_BytesValue,
+    testCase_NegativeEnum,
     allTestsDone :: (?format :: Format) => TestTree
 tests = testGroup
           ("Decode protobuf messages from Python: format " ++ show ?format)
@@ -71,6 +73,7 @@ tests = testGroup
           , testCase_DoubleValue, testCase_FloatValue, testCase_Int64Value
           , testCase_UInt64Value, testCase_Int32Value, testCase_UInt32Value
           , testCase_BoolValue, testCase_StringValue, testCase_BytesValue
+          , testCase_NegativeEnum
           , allTestsDone -- this should always run last
           ]
 
@@ -398,7 +401,7 @@ testCase_DoubleValue = testCaseInFormat "DoubleValue" $ do
   let w = TestProtoWrappers.TestDoubleValue
   expect (w Nothing)
   expect (w (Just 3.5))
- 
+
 testCase_FloatValue = testCaseInFormat "FloatValue" $ do
   let w = TestProtoWrappers.TestFloatValue
   expect (w Nothing)
@@ -450,6 +453,14 @@ testCase_BytesValue = testCaseInFormat "BytesValue" $ do
   expect (w (Just ""))
   expect (w (Just "012"))
 
+testCase_NegativeEnum = testCaseInFormat "NegativeEnum" $ do
+  let w = TestProtoNegativeEnum.WithNegativeEnum . Enumerated . Right
+  expect (w TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_0)
+  expect (w TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_NEGATIVE_1)
+  expect (w TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_1)
+  expect (w TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_NEGATIVE_128)
+  expect (w TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_128)
+
 
 allTestsDone = testCaseInFormat "Receive end of test suite sentinel message" $
    do MultipleFields{..} <- readProto

tests/SimpleEncodeDotProto.hs

@@ -15,6 +15,7 @@ import qualified TestProtoImport
 import qualified TestProtoOneof
 import qualified TestProtoOneofImport
 import qualified TestProtoWrappers
+import qualified TestProtoNegativeEnum
 import           Text.Read (readEither)
 import           System.Environment (getArgs, getProgName)
 import           System.Exit (die)
@@ -274,6 +275,15 @@ testCase_BytesValue = do
   emit (Just "")
   emit (Just "012")
 
+testCase_NegativeEnum :: (?format :: Format) => IO ()
+testCase_NegativeEnum = do
+  let emit = outputMessage . TestProtoNegativeEnum.WithNegativeEnum . Enumerated . Right
+  emit TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_0
+  emit TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_NEGATIVE_1
+  emit TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_1
+  emit TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_NEGATIVE_128
+  emit TestProtoNegativeEnum.NegativeEnumNEGATIVE_ENUM_128
+
 
 main :: IO ()
 main = do
@@ -323,4 +333,7 @@ main = do
   testCase_StringValue
   testCase_BytesValue
 
+  -- Negative enum codes
+  testCase_NegativeEnum
+
   outputMessage (MultipleFields 0 0 0 0 "All tests complete" False)

tests/TestCodeGen.hs

@@ -255,6 +255,7 @@ compileTestDotProtos logger recStyle decodedStringType = do
       protoFiles =
         [ "test_proto.proto"
         , "test_proto_import.proto"
+        , "test_proto_negative_enum.proto"
         , "test_proto_oneof.proto"
         , "test_proto_oneof_import.proto"
         {- These tests have been temporarily removed to pass CI.
@@ -263,6 +264,7 @@ compileTestDotProtos logger recStyle decodedStringType = do
         -}
         , "test_proto_nested_message.proto"
         , "test_proto_wrappers.proto"
+        , "test_proto_negative_enum.proto"
         ]
 
   forM_ protoFiles $ \protoFile -> do

tests/check_simple_dot_proto.py

@@ -2,12 +2,13 @@
 import io
 import sys
 # Import protoc generated {de,}serializers (generated from test_proto{,_import}.proto)
-from google.protobuf             import json_format
-from test_proto_pb2              import *
-from test_proto_import_pb2       import WithNesting as ImportedWithNesting
-from test_proto_oneof_pb2        import Something, WithImported, DUMMY0, DUMMY1
-from test_proto_oneof_import_pb2 import WithOneof
-from test_proto_wrappers_pb2     import *
+from google.protobuf              import json_format
+from test_proto_pb2               import *
+from test_proto_import_pb2        import WithNesting as ImportedWithNesting
+from test_proto_negative_enum_pb2 import *
+from test_proto_oneof_pb2         import Something, WithImported, DUMMY0, DUMMY1
+from test_proto_oneof_import_pb2  import WithOneof
+from test_proto_wrappers_pb2      import *
 
 # Python 3.7 or newer requires this
 sys.stdin.reconfigure(encoding='iso-8859-1', newline='')
@@ -495,6 +496,21 @@ def read_proto(cls, skip_if_json=False):
 assert case_BytesValue_C.HasField('wrapper')
 assert case_BytesValue_C.wrapper.value == b"012"
 
+case_NegativeEnum_A = read_proto(WithNegativeEnum)
+assert case_NegativeEnum_A.v == NEGATIVE_ENUM_0
+
+case_NegativeEnum_B = read_proto(WithNegativeEnum)
+assert case_NegativeEnum_B.v == NEGATIVE_ENUM_NEGATIVE_1
+
+case_NegativeEnum_C = read_proto(WithNegativeEnum)
+assert case_NegativeEnum_C.v == NEGATIVE_ENUM_1
+
+case_NegativeEnum_D = read_proto(WithNegativeEnum)
+assert case_NegativeEnum_D.v == NEGATIVE_ENUM_NEGATIVE_128
+
+case_NegativeEnum_E = read_proto(WithNegativeEnum)
+assert case_NegativeEnum_E.v == NEGATIVE_ENUM_128
+
 # Wait for the special 'done' messsage
 done_msg = read_proto(MultipleFields)
 assert done_msg.multiFieldString == "All tests complete"

tests/decode.sh

@@ -14,6 +14,7 @@ ghc                                         \
     $hsTmpDir/TestProtoOneof.hs             \
     $hsTmpDir/TestProtoOneofImport.hs       \
     $hsTmpDir/TestProtoWrappers.hs          \
+    $hsTmpDir/TestProtoNegativeEnum.hs      \
     tests/Test/Dhall/Orphan.hs              \
     tests/SimpleDecodeDotProto.hs           \
     >/dev/null

tests/encode.sh

@@ -14,6 +14,7 @@ ghc                                         \
     $hsTmpDir/TestProtoOneof.hs             \
     $hsTmpDir/TestProtoOneofImport.hs       \
     $hsTmpDir/TestProtoWrappers.hs          \
+    $hsTmpDir/TestProtoNegativeEnum.hs      \
     tests/Test/Dhall/Orphan.hs              \
     tests/SimpleEncodeDotProto.hs           \
     >/dev/null

tests/send_simple_dot_proto.py

@@ -2,13 +2,14 @@
 import sys
 import os
 # Import protoc generated {de,}serializers (generated from test_proto{,_import}.proto)
-from google.protobuf               import json_format
-from google.protobuf.wrappers_pb2  import *
-from test_proto_pb2                import *
-import test_proto_import_pb2       as test_proto_import
-import test_proto_oneof_pb2        as test_proto_oneof
-import test_proto_oneof_import_pb2 as test_proto_oneof_import
-import test_proto_wrappers_pb2     as test_proto_wrappers
+from google.protobuf                import json_format
+from google.protobuf.wrappers_pb2   import *
+from test_proto_pb2                 import *
+import test_proto_import_pb2        as test_proto_import
+import test_proto_negative_enum_pb2 as test_proto_negative_enum
+import test_proto_oneof_pb2         as test_proto_oneof
+import test_proto_oneof_import_pb2  as test_proto_oneof_import
+import test_proto_wrappers_pb2      as test_proto_wrappers
 
 # Python 3.7 or newer requires this
 sys.stdout.reconfigure(encoding='iso-8859-1')
@@ -285,5 +286,12 @@ def write_proto(msg):
 write_proto(test_proto_wrappers.TestBytesValue(wrapper=BytesValue(value=b"")))
 write_proto(test_proto_wrappers.TestBytesValue(wrapper=BytesValue(value=b"012")))
 
+# Test NegativeEnum
+write_proto(test_proto_negative_enum.WithNegativeEnum(v=test_proto_negative_enum.NEGATIVE_ENUM_0))
+write_proto(test_proto_negative_enum.WithNegativeEnum(v=test_proto_negative_enum.NEGATIVE_ENUM_NEGATIVE_1))
+write_proto(test_proto_negative_enum.WithNegativeEnum(v=test_proto_negative_enum.NEGATIVE_ENUM_1))
+write_proto(test_proto_negative_enum.WithNegativeEnum(v=test_proto_negative_enum.NEGATIVE_ENUM_NEGATIVE_128))
+write_proto(test_proto_negative_enum.WithNegativeEnum(v=test_proto_negative_enum.NEGATIVE_ENUM_128))
+
 # Send the special 'done' message
 write_proto(MultipleFields(multiFieldString = "All tests complete"))