KMM集成Realm/Atlas时Schema验证失败：未知类型PelletToNumberUsedMapEntry

问题翻译 #

我正在开发一个Kotlin Multiplatform（KMM）应用，尝试与Realm/Atlas集成。调用Realm.open(it)时抛出如下异常：

IllegalStateException@29576} "java.lang.IllegalStateException:
[RLM_ERR_SCHEMA_VALIDATION_FAILED]: Schema validation failed due to
the following errors: Property 'PelletInsertionVisit.pelletMapAsList'
of type 'array' has unknown object type 'PelletToNumberUsedMapEntry'

相关类代码：

class PelletInsertionVisit : RealmObject {
    @PrimaryKey
    var _id: String = ""
    var visitDate = LocalDateTime.now().toEpochSecond(ZoneOffset.UTC)
    var pelletsUsed: RealmList<Pellet> = realmListOf()
    var pelletMapAsList: RealmList<PelletToNumberUsedMapEntry> = realmListOf() // 记录 pellet 名称到使用数量的映射

    var signedInUser: String = "UNKNOWN" // 执行更新操作的用户名

    override fun toString(): String {
        return "PelletInsertionVisit(visitDate=$visitDate, pelletsUsed=$pelletsUsed, pelletMap=$pelletMapAsList, signedInUserUserName='$signedInUser')"
    }
}

嵌入式类代码：

class PelletToNumberUsedMapEntry : EmbeddedRealmObject {
    var pelletKey: String = "NOTSET"
    var numberUsed: Int = 0
}

调用Realm.open(it)前的配置代码：

private fun setupRealmSync() {
    val user = runBlocking { appServiceInstance.currentUser }
    val config = user?.let {
        SyncConfiguration
            .Builder(
                it,
                setOf(UserAccount::class,Pellet::class, PelletInsertionVisit::class, PelletLot::class, Patient::class,
                    Practice::class )
            )
            .initialSubscriptions(rerunOnOpen = true) { realms ->
                add(
                    realms.query<PelletInsertionVisit>(),
                    name = "Pellet Insertion Visit info",   
                    updateExisting = true
                )

                add(realms.query<PelletLot>(), name = "Pellet info", updateExisting = true)
                add(realms.query<Patient>(), name = "Patient info", updateExisting = true)
                add(realms.query<Practice>(), name = "Practice info", updateExisting = true)
                add(realms.query<UserAccount>(), name = "UserAccount info", updateExisting = true)
            }
            .build()
    }
}

目前PelletInsertionVisit已在MongoDB Compass中可见，但系统无法识别PelletToNumberUsedMapEntry类。我原本以为嵌入式对象无需额外配置，请问这是否是问题所在？

解决方案 #

问题的核心正是嵌入式对象PelletToNumberUsedMapEntry未被添加到Realm同步配置的类集合中。虽然嵌入式对象依赖父对象存在，不能独立存储，但在KMM的Realm Sync配置里，所有被引用的Realm对象（包括嵌入式对象）都需要显式声明，否则Realm无法识别该类型，导致Schema验证失败。

具体修改步骤

在SyncConfiguration.Builder的类集合参数中，添加PelletToNumberUsedMapEntry::class：

SyncConfiguration
    .Builder(
        it,
        setOf(UserAccount::class, Pellet::class, PelletInsertionVisit::class, PelletLot::class, Patient::class,
            Practice::class, PelletToNumberUsedMapEntry::class) // 新增该嵌入式类
    )
    .initialSubscriptions(rerunOnOpen = true) { realms ->
        // 订阅逻辑保持不变
        add(realms.query<PelletInsertionVisit>(), name = "Pellet Insertion Visit info", updateExisting = true)
        add(realms.query<PelletLot>(), name = "Pellet info", updateExisting = true)
        add(realms.query<Patient>(), name = "Patient info", updateExisting = true)
        add(realms.query<Practice>(), name = "Practice info", updateExisting = true)
        add(realms.query<UserAccount>(), name = "UserAccount info", updateExisting = true)
    }
    .build()

补充说明

• 你的PelletToNumberUsedMapEntry继承EmbeddedRealmObject的写法是正确的，无需修改。
• 云端Atlas中已存在的PelletInsertionVisit集合，在修改配置后重新同步时，Realm会自动适配嵌入式对象的Schema（只要本地与云端Schema兼容）。

内容的提问来源于stack exchange，提问作者user443654