git.iko.soy/typeable/aeson
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Catch 0 denominators when parsing Ratio
commit56ccd680210087268d0334fe49fd31e483274a1a authorAdam Bergmark <adam@bergmark.nl> dateThu 10 May 2018, 19:10 (8 years ago) parentbc0146d
2 files changed+13−3
compare with master
unifiedsplit
Data/Aeson/Types/FromJSON.hs+6−3 tests/UnitTests.hs+7
Data/Aeson/Types/FromJSON.hs+6−3
@@ -1258,9 +1258,12 @@ instance FromJSONKey Float where
12581258 _ -> Scientific.toRealFloat <$> parseScientificText t
12591259
12601260instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
1261− parseJSON = withObject "Rational" $ \obj ->
1262− (%) <$> obj .: "numerator"
1263− <*> obj .: "denominator"
1261+ parseJSON = withObject "Rational" $ \obj -> do
1262+ numerator <- obj .: "numerator"
1263+ denominator <- obj .: "denominator"
1264+ if denominator == 0
1265+ then fail "Ratio denominator was 0"
1266+ else pure $ numerator % denominator
12641267 {-# INLINE parseJSON #-}
12651268
12661269-- | /WARNING:/ Only parse fixed-precision numbers from trusted input
tests/UnitTests.hs+7
@@ -100,6 +100,7 @@ tests = testGroup "unit" [
100100 , testGroup "SingleMaybeField" singleMaybeField
101101 , testCase "withEmbeddedJSON" withEmbeddedJSONTest
102102 , testCase "SingleFieldCon" singleFieldCon
103+ , testCase "Ratio with denominator 0" ratioDenominator0
103104 ]
104105
105106roundTripCamel :: String -> Assertion
@@ -546,6 +547,12 @@ singleFieldCon :: Assertion
546547singleFieldCon =
547548 assertEqual "fromJSON" (Right (SingleFieldCon 0)) (eitherDecode "0")
548549
550+ratioDenominator0 :: Assertion
551+ratioDenominator0 =
552+ assertEqual "Ratio with denominator 0"
553+ (Left "Error in $: Ratio denominator was 0")
554+ (eitherDecode "{ \"numerator\": 1, \"denominator\": 0 }" :: Either String Rational)
555+
549556deriveJSON defaultOptions{omitNothingFields=True} ''MyRecord
550557
551558deriveToJSON defaultOptions ''Foo