Client Queries fail on any nonNull perameters with coerced null value

[MarcusDunn]

I've set up the graphql-kotlin client to be generated from file (no introspection, instead I copy from /sdl whenever the schema changes). I have several requests working fine (all with nullable parameters), but I have a very simple one failing with the following error GraphQLError(message=Variable 'input' has coerced Null value for NonNull type 'Int!', locations=[SourceLocation(line=1, column=20)], path=null, extensions=null) from what I see online, this is caused by passing a null value (or failing to pass in variables with correct syntax) to a NonNull parameter. But I'm failing to see why that happens here.

here is the signature of the kotlin function from which the failing parts of the schema is generated

fun patient(pID: Int, authContext: GraphQLAuthContext): Patient.Companion.GraphQLPatient

the relevant parts of the generated schema
patient(pID: Int!): Patient!

the .schema file I'm generating the client from

query PatientQuery($pID: Int!) {
    patient(pID: $pID) {
        address
        cellPhone
        email
        firstName
        lastName
        middleName
        pID
        workPhone
    }
}

and the code that I call the client with

    @Test
    internal fun testPatient() {
        val patientsQuery = PatientQuery(client.value)
        runBlocking {
            val variables = PatientQuery.Variables(pID = 20)
            val result = patientsQuery.execute(variables)
            assert(result.errors.isNullOrEmpty()) { "errors is not null or empty: $result with the following variables: $variables" }
            assert(result.data != null)
        }
    }

which consistently throws the following (with my added debugging info from the assert)

java.lang.AssertionError: errors is not null or empty: GraphQLResponse(data=null, errors=[GraphQLError(message=Variable 'pID' has coerced Null value for NonNull type 'Int!', locations=[SourceLocation(line=1, column=20)], path=null, extensions=null)], extensions=null) with the following variables: Variables(pID=20)

And finally here's the graphql-koltin portions of gradle.build file (I'm using "4.0.0-alpha.10")

dependencies {
    implementation("com.expediagroup:graphql-kotlin-spring-server:${graphQLKotlin.version}")
    implementation("com.expediagroup:graphql-kotlin-spring-client:${graphQLKotlin.version}")
}

plugins {
    id("com.expediagroup.graphql") version "4.0.0-alpha.10"
}

val graphqlGenerateTestClient by tasks.getting(com.expediagroup.graphql.plugin.gradle.tasks.GraphQLGenerateClientTask::class) {
    clientType.set(com.expediagroup.graphql.plugin.generator.GraphQLClientType.WEBCLIENT)
    packageName.set("com.leftindust.mediq")
    schemaFileName.set("${project.projectDir}/src/main/resources/schema.graphql")
    queryFileDirectory.set("${project.projectDir}/src/main/resources/queries")
}

Any help would be appreciated! if this actually unexpected behaviour I'll open up an issue, but I imagine I am just using the library incorrectly and this seems the place to put that.

[smyrick]

@MarcusDunn Is there a github project you can link to as a demo?

If not can you share the result of printing the server schema to verify what the server is using.

[MarcusDunn]

https://github.com/leftindust/mediq-kotlin

here is the link, I do not think you'll get it to run (if that's what you were thinking to do) without a backing firebase project (of which I obviously cannot give) so here is the whole schema from /sdl

schema {
  query: Query
  mutation: Mutation
}

"Directs the executor to include this field or fragment only when the `if` argument is true"
directive @include(
    "Included when true."
    if: Boolean!
  ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT

"Directs the executor to skip this field or fragment when the `if`'argument is true."
directive @skip(
    "Skipped when true."
    if: Boolean!
  ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT

"Marks the field or enum value as deprecated"
directive @deprecated(
    "The reason for the deprecation"
    reason: String = "No longer supported"
  ) on FIELD_DEFINITION | ENUM_VALUE

"Exposes a URL that specifies the behaviour of this scalar."
directive @specifiedBy(
    "The URL that specifies the behaviour of this scalar."
    url: String!
  ) on SCALAR

type Action {
  columnName: String
  endTime: Time
  friendlyName: String
  permissionType: CRUD!
  referencedTableName: String!
  rowId: Int
  startTime: Time
}

type AlwaysNull {
  nothing: Int
}

type Group {
  name: String!
}

type Mutation {
  addPatient(patient: PatientInput!): Patient!
  createAdminGroup(groupName: String): String!
  findGroup(groupName: String!): [Action!]!
  removeGroup(groupName: String!): AlwaysNull!
  updatePatient(patient: PatientInput!): Patient!
}

type Patient {
  address: String
  cellPhone: String
  dateOfBirth: Time
  email: String
  firstName: String
  group: Group
  lastName: String
  middleName: String
  pID: Int!
  user: User
  workPhone: String
}

type Query {
  patient(pID: Int!): Patient!
  patients(from: Int, sortedBy: SortableField, to: Int): [Patient!]!
}

type Time {
  day: Int
  month: Int
  unixTime: String
  year: Int
}

type User {
  group: Group
  uniqueId: String!
}

enum CRUD {
  Create
  Delete
  Read
  Update
}

enum SortableField {
  first_name
  last_name
  middle_name
  patient_id
  pid
}

input GroupInput {
  name: String!
}

input PatientInput {
  address: String
  cellPhone: String
  dateOfBirth: TimeInput
  email: String
  firstName: String
  group: GroupInput
  lastName: String
  middleName: String
  pID: Int!
  user: UserInput
  workPhone: String
}

input TimeInput {
  day: Int
  month: Int
  unixTime: String
  year: Int
}

input UserInput {
  group: GroupInput
  uniqueId: String!
}

Something else that I thought may be reasonable to include is the problem generated class

package com.leftindust.mediq

import com.expediagroup.graphql.client.GraphQLWebClient
import com.expediagroup.graphql.types.GraphQLResponse
import kotlin.Int
import kotlin.String
import kotlin.Unit
import org.springframework.web.reactive.function.client.WebClient

const val PATIENT_QUERY: String =
    "query PatientQuery(${'$'}pID: Int!) {\n    patient(pID: ${'$'}pID) {\n        address\n        cellPhone\n        email\n        firstName\n        lastName\n        middleName\n        pID\n        workPhone\n    }\n}"

class PatientQuery(
  private val graphQLClient: GraphQLWebClient
) {
  suspend fun execute(variables: PatientQuery.Variables,
      requestBuilder: WebClient.RequestBodyUriSpec.() -> Unit = {}):
      GraphQLResponse<PatientQuery.Result> = graphQLClient.execute(PATIENT_QUERY, "PatientQuery",
      variables, requestBuilder)

  data class Variables(
    val pID: Int
  )

  data class Patient(
    val address: String?,
    val cellPhone: String?,
    val email: String?,
    val firstName: String?,
    val lastName: String?,
    val middleName: String?,
    val pID: Int,
    val workPhone: String?
  )

  data class Result(
    val patient: PatientQuery.Patient
  )
}

[MarcusDunn]

I fixed the issue by renaming pID, I to pid. I have no idea why that fixed it, my final query and schema were as follows:

test function:

    @Test
    internal fun `test Patient does not throw`() {
        val patientQuery = PatientQuery(client.value)

        runBlocking {
            val result = patientQuery.execute(
                PatientQuery.Variables(
                    pid = 21953564
                )
            )
            assert(result.errors.isNullOrEmpty()) { "result: $result" }
        }
    }

query

query patientQuery($pid: Int!) {
    patient(pid: $pid) {
        firstName
    }
}

a small portion of the schema

type Query {
    patient(pid: Int!): Patient!
}

and the generating function signature

fun patient(pid: Int, authContext: GraphQLAuthContext): GraphQLPatient

[smyrick]

Hmm interesting. I am not as familiar with the client generator code.

I would imagine that it is somewhere here that may be sending null to the server,

graphql-kotlin/plugins/client/graphql-kotlin-client-generator/src/main/kotlin/com/expediagroup/graphql/plugin/client/generator/GraphQLClientGenerator.kt

Line 112 in 4873c3d

val variableCode = if (variableType != null) {

This seems like a bug, but if you have a fix we can keep it as a discussion until we can reproduce it with a test in the /examples