切换到GraphQL15.5.1返回空数组后，将导致“无法返回空值”错误

Question

编辑:您可以跳到末尾，以获得代码框中错误的简化示例。

我正在将我的阿波罗计划升级到新版本的graphql，我得到了一个奇怪的错误。在google上找不到任何与此场景相匹配的结果。当我试图返回具有非空字段(包括day)的ObjectTypes DrivingActivitiesDailySummaryType的空数组时，它会抛出一个“非空字段DrivingActivitiesDailySummaryType.day不能返回null”。这在14.7.0版中起了作用。这里发生了什么事？如何避免呢？我认为正常的行为是允许空数组，并且在changelog中找不到任何指示这种类型更改的东西。

我的解析器当前只返回一个硬编码的值，用于测试：

@Query(() => DrivingActivityPayload)
    public async totalDrivingActivity(
        @Ctx("user") userContext: UserContext,
        @Args() input: DrivingActivitiesQueryInput
    ): Promise<DrivingActivityPayload> {
        return {
            totalSummary: { speed: 1, activities: 1, duration: 1, distance: 1 },
            dailySummaries: [],
            monthlySummaries: [],
        }
    }

我的有效载荷分配：

@ObjectType()
export class DrivingActivityPayload {
    @Field(() => DrivingActivitiesTotalSummaryType)
    public totalSummary: DrivingActivitiesTotalSummaryType

    @Field(() => DrivingActivitiesDailySummaryType)
    public dailySummaries: DrivingActivitiesDailySummaryType[]

    @Field(() => DrivingActivitiesMonthlySummaryType)
    public monthlySummaries: DrivingActivitiesMonthlySummaryType[]

    constructor(
        totalSummary: DrivingActivitiesTotalSummaryType,
        dailySummaries: DrivingActivitiesDailySummaryType[],
        monthlySummaries: DrivingActivitiesMonthlySummaryType[]
    ) {
        this.totalSummary = new DrivingActivitiesTotalSummaryType(totalSummary)
        this.dailySummaries = dailySummaries.map(summary => new DrivingActivitiesDailySummaryType(summary))
        this.monthlySummaries = monthlySummaries.map(summary => new DrivingActivitiesMonthlySummaryType(summary))
    }
}

GraphQL错误：

  "errors": [
    {
      "message": "Cannot return null for non-nullable field DrivingActivitiesDailySummaryType.day.",
      "locations": [
        {
          "line": 18,
          "column": 7
        }
      ],
      "path": [
        "totalDrivingActivity",
        "dailySummaries",
        "day"
      ],
      "extensions": {
        "code": "INTERNAL_SERVER_ERROR",
        "exception": {
          "stacktrace": [
            "Error: Cannot return null for non-nullable field DrivingActivitiesDailySummaryType.day.",
            "    at completeValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:559:13)",
            "    at resolveField ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:472:19)",
            "    at executeFields ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:292:18)",
            "    at collectAndExecuteSubfields ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:748:10)",
            "    at completeObjectValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:738:10)",
            "    at completeValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:590:12)",
            "    at completeValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:556:21)",
            "    at resolveField ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:472:19)",
            "    at executeFields ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:292:18)",
            "    at collectAndExecuteSubfields ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:748:10)",
            "    at completeObjectValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:738:10)",
            "    at completeValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:590:12)",
            "    at completeValue ([PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:556:21)",
            "    at [PROJECT-FOLDER]/node_modules/graphql/execution/execute.js:469:16",
            "    at processTicksAndRejections (node:internal/process/task_queues:96:5)",
            "    at async Promise.all (index 0)"
          ]
        }
      }
    }
  ],
  "data": null
}

DrivingActivitiesDailySummaryType设计(尽管这并不重要)：

@ObjectType()
export class DrivingActivitiesDailySummaryType {
    @Field(() => Date)
    public day: Date

    @Field()
    public distance: number

    @Field()
    public activities: number

    constructor(summary: DrivingActivitiesDailySummaryType) {
        this.day = summary.day
        this.activities = summary.activities
        this.distance = summary.distance
    }
}

编辑:这里有一个带有再现错误的沙箱链接：https://codesandbox.io/s/heuristic-jepsen-5frr3?file=/package.json (我不知道如何更改默认的终端行为，所以您必须用"+“图标打开一个新的终端，然后运行"npm”)，当使用提供的package.json (有新版本)时，错误会被再现，当您用Pack-old.json切换package.json的内容时-old.json( graphql和type-graphql的旧版本)没有错误。

EDIT2:您可能需要将"/graphql“添加到代码框链接中才能正常工作

Answer 1

您应该将每日和每月的摘要定义为数组：

@Field(() => [DrivingActivitiesDailySummaryType])
public dailySummaries: DrivingActivitiesDailySummaryType[]

@Field(() => [DrivingActivitiesMonthlySummaryType])
public monthlySummaries: DrivingActivitiesMonthlySummaryType[]