IllegalArgumentException when Deleting Class Not in Schema with AutomaticSchemaMigration

[sirambd]

Problem

When migrating with AutomaticSchemaMigration, I get an IllegalArgumentException because I want to delete the Signature class, but it's no longer in the schema list because it doesn't make sense to keep it in the schema migration list.
I even tried with enumerates and it didn't work.

Here's an example:

val MAILBOX_CONTENT_MIGRATION = AutomaticSchemaMigration { migrationContext ->
    val oldRealm = migrationContext.oldRealm
    val newRealm = migrationContext.newRealm
    if (oldRealm.schemaVersion() < 9 && newRealm.schemaVersion() >= 9) {
        migrationContext.newRealm.delete("Signature")
    }
}

Exception

java.lang.IllegalArgumentException: Schema does not contain a class named 'Signature'
2023-10-16 19:48:36.541 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.schema.SchemaMetadata$DefaultImpls.getOrThrow(CachedClassKeyMap.kt:40)
2023-10-16 19:48:36.541 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.schema.CachedSchemaMetadata.getOrThrow(CachedClassKeyMap.kt:89)
2023-10-16 19:48:36.542 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.dynamic.DynamicMutableRealmImpl.query(DynamicMutableRealmImpl.kt:65)
2023-10-16 19:48:36.542 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.dynamic.DynamicRealm$DefaultImpls.query$default(DynamicRealm.kt:45)
2023-10-16 19:48:36.542 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.dynamic.DynamicMutableRealmImpl.delete(DynamicMutableRealmImpl.kt:106)
2023-10-16 19:48:36.542 24243-24443 System.err              com.infomaniak.mail                  W  	at com.infomaniak.mail.data.cache.RealmMigrationsKt.MAILBOX_CONTENT_MIGRATION$lambda$2(RealmMigrations.kt:36)
2023-10-16 19:48:36.542 24243-24443 System.err              com.infomaniak.mail                  W  	at com.infomaniak.mail.data.cache.RealmMigrationsKt.$r8$lambda$m8gC0trFnAvmBIhjEaMMi3q8yFo(Unknown Source:0)
2023-10-16 19:48:36.543 24243-24443 System.err              com.infomaniak.mail                  W  	at com.infomaniak.mail.data.cache.RealmMigrationsKt$$ExternalSyntheticLambda2.migrate(Unknown Source:0)
2023-10-16 19:48:36.543 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.ConfigurationImpl.lambda$3$lambda$2(ConfigurationImpl.kt:171)
2023-10-16 19:48:36.543 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.ConfigurationImpl$$ExternalSyntheticLambda0.migrate(Unknown Source:4)
2023-10-16 19:48:36.543 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.interop.realmcJNI.realm_open(Native Method)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.interop.realmc.realm_open(realmc.java:426)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.interop.RealmInterop.realm_open(RealmInterop.kt:202)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.ConfigurationImpl$openRealm$2.invoke(ConfigurationImpl.kt:114)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.ConfigurationImpl$openRealm$2.invoke(ConfigurationImpl.kt:113)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.interop.NativePointerKt.use(NativePointer.kt:53)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.ConfigurationImpl.openRealm$suspendImpl(ConfigurationImpl.kt:113)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.ConfigurationImpl.openRealm(Unknown Source:0)
2023-10-16 19:48:36.544 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.RealmImpl$1.invokeSuspend(RealmImpl.kt:132)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:108)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:280)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:85)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source:1)
2023-10-16 19:48:36.545 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.platform.CoroutineUtilsSharedJvmKt.runBlocking(CoroutineUtilsSharedJvm.kt:22)
2023-10-16 19:48:36.546 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.platform.CoroutineUtilsSharedJvmKt.runBlocking$default(CoroutineUtilsSharedJvm.kt:21)
2023-10-16 19:48:36.546 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.RealmImpl.<init>(RealmImpl.kt:114)
2023-10-16 19:48:36.546 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.RealmImpl.<init>(Unknown Source:0)
2023-10-16 19:48:36.546 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.internal.RealmImpl$Companion.create$io_realm_kotlin_library(RealmImpl.kt:293)
2023-10-16 19:48:36.546 24243-24443 System.err              com.infomaniak.mail                  W  	at io.realm.kotlin.Realm$Companion.open(Realm.kt:83)
2023-10-16 19:48:36.546 24243-24443 System.err              com.infomaniak.mail                  W  	at com.infomaniak.mail.data.cache.RealmDatabase.newMailboxContentInstance(RealmDatabase.kt:80)
2023-10-16 19:48:36.547 24243-24443 System.err              com.infomaniak.mail                  W  	at com.infomaniak.mail.data.cache.RealmDatabase.getNewMailboxContentInstance(RealmDatabase.kt:79)
2023-10-16 19:48:36.547 24243-24443 System.err              com.infomaniak.mail                  W  	at com.infomaniak.mail.data.cache.RealmDatabase$MailboxContent$invoke$1.invokeSuspend(RealmDatabase.kt:85)
2023-10-16 19:48:36.547 24243-24443 System.err              com.infomaniak.mail                  W  	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)

Version
Realm 1.11.1

Solution

I haven't found any other way than to leave the class in the schema migrations, but ideally it would be nice to be able to delete an existing class even if it no longer appears in the current schema migrations.

• Perhaps the oldRealm could contain a delete method, which would allow deletion based on the previous schema only (not a fan, as it would be confusing).
• Or a way to temporarily put the schema in the list until the migration is complete.
• Or just a way to delete without checking the schema during migration.

Alternatives

No response

How important is this improvement for you?

I would like to have it but have a workaround

Feature would mainly be used with

Local Database only

[clementetb]

It is not required to delete the class. AutomaticSchemaMigration automatically migrates the schema.

During an AutomaticSchemaMigration, you only need to move the data from the old classes/properties to the new ones.

[sirambd]

@clementetb Even in the case of migrating the data, I'd like to be able to remove it from the list from within the RealmConfiguration.Builder, in itself the migration is fine, there's nothing to worry about.
But it's just that I'd like to remove the class from the list as it's useless, however doing this creates a problem even using enumerates which returns null as it requires the class to be left in the list.

[clementetb]

It is not required to add the old class to the configuration's schema list.

The way that automatic migration works is that you update your schema, pass it to the configuration, and then open the Realm. No need to keep references to the "old schema".

If while opening the Realm a schema variation is detected, then the migration codeblock will be triggered. During the migration you are given two Dynamic Realms, an instance before the schema variation and an instance with the new schema. You can use them to move any data from the old to the new.

[github-actions]

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