I have a custom scalar type of `ClosedRange lt LocalDate gt

Question

I have a custom scalar type of `ClosedRange lt LocalDate gt ` I have defined and registered a `Coercing lt ClosedRange lt LocalDate gt String gt ` and via debugger confirmed the coercer is being called at runtime but I get a Jackson exception when parsing an Input ```Caused by com fasterxml jackson databind exc InvalidDefinitionException Cannot construct instance of `kotlin ranges ClosedRange` no Creators like default constructor exist abstract types either need to be mapped to concrete types have custom deserializer or contain additional type information at Source UNKNOWN line 1 column 1 through reference chain my MyInput range ``` Any idea why that would be happening

Dariusz Kuc · Answer

how did you define your `ClosedRange lt LocalDate gt ` Jackson requires default empty constructor or you will have to annotate your data class

rocketraman · Answer

`ClosedRange` is a Kotlin stdlib type

rocketraman · Answer

Maybe I misunderstand something about the interaction between coercers and Jackson I thought if I defined a coercer then Jackson would not be invoked to instantiate that type as my coercer instantiates it

rocketraman · Answer

Could it have something to do with the fact that `ClosedRange` is an interface type The underlying type is `ComparableRange` private to stdlib

Dariusz Kuc · Answer

where was it thrown from stacktrace

rocketraman · Answer

``` at com fasterxml jackson databind ObjectMapper convert ObjectMapper java 4236 ~ jackson databind 2 11 4 jar 2 11 4 at com fasterxml jackson databind ObjectMapper convertValue ObjectMapper java 4167 ~ jackson databind 2 11 4 jar 2 11 4 at com expediagroup graphql generator execution FunctionDataFetcher convertValue FunctionDataFetcher kt 161 ~ graphql kotlin schema generator 4 1 1 jar 4 1 1 at com expediagroup graphql generator execution FunctionDataFetcher convertArgumentToObject FunctionDataFetcher kt 142 ~ graphql kotlin schema generator 4 1 1 jar 4 1 1 at com expediagroup graphql generator execution FunctionDataFetcher mapParameterToValue FunctionDataFetcher kt 114 ~ graphql kotlin schema generator 4 1 1 jar 4 1 1 at com expediagroup graphql generator execution FunctionDataFetcher getParameters FunctionDataFetcher kt 90 ~ graphql kotlin schema generator 4 1 1 jar 4 1 1 at com expediagroup graphql generator execution FunctionDataFetcher get FunctionDataFetcher kt 69 ~ graphql kotlin schema generator 4 1 1 jar 4 1 1 at graphql execution ExecutionStrategy fetchField ExecutionStrategy java 270 ~ graphql java 16 2 jar at graphql execution ExecutionStrategy resolveFieldWithInfo ExecutionStrategy java 203 ~ graphql java 16 2 jar at graphql execution AsyncExecutionStrategy execute AsyncExecutionStrategy java 60 ~ graphql java 16 2 jar at graphql execution ExecutionStrategy completeValueForObject ExecutionStrategy java 646 ~ graphql java 16 2 jar at graphql execution ExecutionStrategy completeValue ExecutionStrategy java 438 ~ graphql java 16 2 jar at graphql execution ExecutionStrategy completeField ExecutionStrategy java 390 ~ graphql java 16 2 jar at graphql execution ExecutionStrategy lambda$resolveFieldWithInfo$1 ExecutionStrategy java 205 ~ graphql java 16 2 jar at java util concurrent CompletableFuture uniApplyNow CompletableFuture java 680 ~ at java util concurrent CompletableFuture uniApplyStage CompletableFuture java 658 ~ at java util concurrent CompletableFuture thenApply CompletableFuture java 2094 ~ at graphql execution ExecutionStrategy resolveFieldWithInfo ExecutionStrategy java 204 ~ graphql java 16 2 jar at graphql execution AsyncExecutionStrategy execute AsyncExecutionStrategy java 60 ~ graphql java 16 2 jar at graphql execution Execution executeOperation Execution java 165 ~ graphql java 16 2 jar at graphql execution Execution execute Execution java 104 ~ graphql java 16 2 jar at graphql GraphQL execute GraphQL java 557 ~ graphql java 16 2 jar at graphql GraphQL parseValidateAndExecute GraphQL java 482 ~ graphql java 16 2 jar at graphql GraphQL executeAsync GraphQL java 446 ~ graphql java 16 2 jar at com expediagroup graphql server execution GraphQLRequestHandler executeRequest$suspendImpl GraphQLRequestHandler kt 45 ~ graphql kotlin server 4 1 1 jar 4 1 1 at com expediagroup graphql server execution GraphQLRequestHandler executeRequest GraphQLRequestHandler kt ~ graphql kotlin server 4 1 1 jar 4 1 1 at com expediagroup graphql server execution GraphQLServer execute$suspendImpl GraphQLServer kt 48 ~ graphql kotlin server 4 1 1 jar 4 1 1 at com expediagroup graphql server execution GraphQLServer execute GraphQLServer kt ~ graphql kotlin server 4 1 1 jar 4 1 1 lt my call handler here gt Caused by com fasterxml jackson databind exc InvalidDefinitionException lt jackson databind classes here gt ```

Dariusz Kuc · Answer

ah so it is from <https github com ExpediaGroup graphql kotlin blob master generator graphql kotlin schema generator src main kotlin com expediagroup graphql generator execution FunctionDataFetcher kt L161|https github com ExpediaGroup graphql kotlin blob master generator graphql kotli expediagroup graphql generator execution FunctionDataFetcher kt>

rocketraman · Answer

Implying

Dariusz Kuc · Answer

If I remember right we had to add this logic to correctly cast the input arguments from data fetching environment it s been a while

rocketraman · Answer

So what are my options

Dariusz Kuc · Answer

you could look into creating custom data fetcher that extends default function data fetcher and override `mapParameterToValue` with custom logic to handle closed range

rocketraman · Answer

Thx I ll give it a shot

rocketraman · Answer

Hmm the custom data fetcher operates on the parent type that contains the `ClosedRange` field So do I need to add special logic for every type where I use `ClosedRange` yuck

Dariusz Kuc · Answer

based on the above stacktrace issue is when using this custom scalar as input gt this implies that it is a function

Dariusz Kuc · Answer

so you need custom <https github com ExpediaGroup graphql kotlin blob master generator graphql kotlin schema generator src main kotlin com expediagroup graphql generator execution KotlinDataFetcherFactoryProvider kt|https github com ExpediaGroup graphql kotlin blob master generator graphql kotli graphql generator execution KotlinDataFetcherFactoryProvider kt> that creates an instance of your custom function data fetcher

Dariusz Kuc · Answer

for properties default data fetcher should be fine and values should be automatically coerced

rocketraman · Answer

Doesn t seem `ClosedRange` is a property of my input data class type and when `mapParameterToValue` is called the `param` value is the input data class type Just tried it with the debugger

Dariusz Kuc · Answer

yeah if it is a property on the input class that logic there attempts to serialize the whole object

Dariusz Kuc · Answer

you could try annotating your input data class with custom serializer converter info that describes how to handle the closed range

rocketraman · Answer

I tried to create a custom Jackson `StdDeserializer` but this is what seems to be happening serialized input on the wire gt coercer deserializes into `ClosedRange lt LocalDate gt ` gt something serializes `ClosedRange lt LocalDate gt ` into crazy JSON as the java time objects have lots of internal state gt custom deserializer runs with crazy JSON

rocketraman · Answer

I can certainly extract what I need from the crazy JSON but this seems really inelegant and inefficient

Shane Myrick · Answer

You need to create your custom object mapper and make sure that gets passed in and used in the `FunctionDataFetcher` <https github com ExpediaGroup graphql kotlin blob a6b957c999398c741cdfbc955fb86243ea211094 generator graphql kotlin schema generator src main kotlin com expediagroup graphql generator execution FunctionDataFetcher kt L55 L59|https github com ExpediaGroup graphql kotlin blob a6b957c999398c741cdfbc955fb862 expediagroup graphql generator execution FunctionDataFetcher kt> As mentioned above you can customize the how `FunctionDataFetcher` gets created with `KotlinDataFetcherFactoryProvider`

rocketraman · Answer

I tried that < Shane Myrick> the FunctionDataFetcher gets the whole Input object never just the `ClosedRange lt LocalDate gt ` property I m not going to create custom fetchers for every object that happens to have a property of that type

rocketraman · Answer

I created this issue with a working workaround but there is some weird multi level deserialization gt serialization gt deserialization happening <https github com ExpediaGroup graphql kotlin issues 1220>