diff --git a/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/data/PluginDataExtensions.kt b/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/data/PluginDataExtensions.kt
index 8523353bd..4681f1394 100644
--- a/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/data/PluginDataExtensions.kt
+++ b/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/data/PluginDataExtensions.kt
@@ -1,15 +1,63 @@
-@file:Suppress("unused", "INAPPLICABLE_JVM_NAME")
+@file:Suppress("unused", "INAPPLICABLE_JVM_NAME", "INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
 
 package net.mamoe.mirai.console.data
 
 import net.mamoe.mirai.console.data.PluginDataExtensions.withDefault
 import net.mamoe.mirai.console.internal.data.ShadowMap
+import net.mamoe.mirai.console.util.ConsoleExperimentalAPI
+import kotlin.internal.LowPriorityInOverloadResolution
 
 /**
  * [PluginData] 相关一些扩展
  */
 public object PluginDataExtensions {
 
+    @ConsoleExperimentalAPI
+    public open class NotNullMap<K, V> internal constructor(
+        private val delegate: Map<K, V>
+    ) : Map<K, V> by delegate {
+        override fun get(key: K): V =
+            delegate[key] ?: error("Internal error: delegate[key] returned null for NotNullMap.get")
+
+        @Deprecated(
+            "getOrDefault on NotNullMap always returns the value in the map, and defaultValue will never be returned.",
+            level = DeprecationLevel.WARNING,
+            replaceWith = ReplaceWith("this.get(key)")
+        )
+        override fun getOrDefault(key: K, defaultValue: V): V {
+            return super.getOrDefault(key, defaultValue)
+        }
+    }
+
+    @Suppress("DELEGATED_MEMBER_HIDES_SUPERTYPE_OVERRIDE") // as designed
+    public class NotNullMutableMap<K, V> internal constructor(
+        private val delegate: MutableMap<K, V>
+    ) : MutableMap<K, V> by delegate, NotNullMap<K, V>(delegate) {
+        override fun get(key: K): V =
+            delegate[key] ?: error("Internal error: delegate[key] returned null for NotNullMutableMap.get")
+
+        @Deprecated(
+            "getOrDefault on NotNullMutableMap always returns the value in the map, and defaultValue will never be returned.",
+            level = DeprecationLevel.WARNING,
+            replaceWith = ReplaceWith("this.get(key)")
+        )
+        override fun getOrDefault(key: K, defaultValue: V): V {
+            return super<MutableMap>.getOrDefault(key, defaultValue)
+        }
+
+        override fun put(key: K, value: V): V {
+            return delegate.put(key, value)
+                ?: error("Internal error: delegate.put(key, value) returned null for NotNullMutableMap.put")
+        }
+
+        @Deprecated(
+            "putIfAbsent on NotNullMutableMap always does nothing.",
+            level = DeprecationLevel.WARNING,
+            replaceWith = ReplaceWith("")
+        )
+        override fun putIfAbsent(key: K, value: V): Nothing? = null
+    }
+
     /**
      * 创建一个代理对象, 当 [Map.get] 返回 `null` 时先放入一个 [LinkedHashMap], 再从 [this] 中取出链接自动保存的 [LinkedHashMap]. ([MutableMap.getOrPut] 的替代)
      *
@@ -17,7 +65,7 @@ public object PluginDataExtensions {
      */
     @JvmName("withEmptyDefaultMapImmutable")
     @JvmStatic
-    public fun <K, InnerE, InnerV> SerializerAwareValue<MutableMap<K, Map<InnerE, InnerV>>>.withEmptyDefault(): SerializerAwareValue<MutableMap<K, Map<InnerE, InnerV>>> {
+    public fun <K, InnerE, InnerV> SerializerAwareValue<MutableMap<K, Map<InnerE, InnerV>>>.withEmptyDefault(): SerializerAwareValue<NotNullMutableMap<K, Map<InnerE, InnerV>>> {
         return this.withDefault { LinkedHashMap() }
     }
 
@@ -27,7 +75,7 @@ public object PluginDataExtensions {
      */
     @JvmName("withEmptyDefaultMap")
     @JvmStatic
-    public fun <K, InnerE, InnerV> SerializerAwareValue<MutableMap<K, MutableMap<InnerE, InnerV>>>.withEmptyDefault(): SerializerAwareValue<MutableMap<K, MutableMap<InnerE, InnerV>>> {
+    public fun <K, InnerE, InnerV> SerializerAwareValue<MutableMap<K, MutableMap<InnerE, InnerV>>>.withEmptyDefault(): SerializerAwareValue<NotNullMutableMap<K, MutableMap<InnerE, InnerV>>> {
         return this.withDefault { LinkedHashMap() }
     }
 
@@ -38,7 +86,7 @@ public object PluginDataExtensions {
      */
     @JvmName("withEmptyDefaultListImmutable")
     @JvmStatic
-    public fun <K, E> SerializerAwareValue<MutableMap<K, List<E>>>.withEmptyDefault(): SerializerAwareValue<MutableMap<K, List<E>>> {
+    public fun <K, E> SerializerAwareValue<MutableMap<K, List<E>>>.withEmptyDefault(): SerializerAwareValue<NotNullMutableMap<K, List<E>>> {
         return this.withDefault { ArrayList() }
     }
 
@@ -48,7 +96,7 @@ public object PluginDataExtensions {
      */
     @JvmName("withEmptyDefaultList")
     @JvmStatic
-    public fun <K, E> SerializerAwareValue<MutableMap<K, MutableList<E>>>.withEmptyDefault(): SerializerAwareValue<MutableMap<K, MutableList<E>>> {
+    public fun <K, E> SerializerAwareValue<MutableMap<K, MutableList<E>>>.withEmptyDefault(): SerializerAwareValue<NotNullMutableMap<K, MutableList<E>>> {
         return this.withDefault { ArrayList() }
     }
 
@@ -59,7 +107,7 @@ public object PluginDataExtensions {
      */
     @JvmName("withEmptyDefaultSetImmutable")
     @JvmStatic
-    public fun <K, E> SerializerAwareValue<MutableMap<K, Set<E>>>.withEmptyDefault(): SerializerAwareValue<MutableMap<K, Set<E>>> {
+    public fun <K, E> SerializerAwareValue<MutableMap<K, Set<E>>>.withEmptyDefault(): SerializerAwareValue<NotNullMutableMap<K, Set<E>>> {
         return this.withDefault { LinkedHashSet() }
     }
 
@@ -69,7 +117,7 @@ public object PluginDataExtensions {
      */
     @JvmName("withEmptyDefaultSet")
     @JvmStatic
-    public fun <K, E> SerializerAwareValue<MutableMap<K, MutableSet<E>>>.withEmptyDefault(): SerializerAwareValue<MutableMap<K, MutableSet<E>>> {
+    public fun <K, E> SerializerAwareValue<MutableMap<K, MutableSet<E>>>.withEmptyDefault(): SerializerAwareValue<NotNullMutableMap<K, MutableSet<E>>> {
         return this.withDefault { LinkedHashSet() }
     }
 
@@ -78,15 +126,47 @@ public object PluginDataExtensions {
      * 创建一个代理对象, 当 [Map.get] 返回 `null` 时先调用 [defaultValueComputer] 并放入 [Map], 再返回调用的返回值
      */
     @JvmStatic
+    @JvmName("withDefaultMapImmutableNotNull")
+    public fun <K, V : Any> SerializerAwareValue<Map<K, V>>.withDefault(defaultValueComputer: (K) -> V): SerializerAwareValue<NotNullMap<K, V>> {
+        @Suppress("UNCHECKED_CAST") // magic
+        return (this as SerializerAwareValue<MutableMap<K, V>>).withDefault(defaultValueComputer) as SerializerAwareValue<NotNullMap<K, V>>
+    }
+
+    /**
+     * 创建一个代理对象, 当 [Map.get] 返回 `null` 时先调用 [defaultValueComputer] 并放入 [Map], 再返回调用的返回值
+     */
+    @JvmStatic
+    @LowPriorityInOverloadResolution
     @JvmName("withDefaultMapImmutable")
     public fun <K, V> SerializerAwareValue<Map<K, V>>.withDefault(defaultValueComputer: (K) -> V): SerializerAwareValue<Map<K, V>> {
         @Suppress("UNCHECKED_CAST") // magic
         return (this as SerializerAwareValue<MutableMap<K, V>>).withDefault(defaultValueComputer) as SerializerAwareValue<Map<K, V>>
     }
 
+    @JvmStatic
+    @JvmName("withDefaultMapNotNull")
+    public fun <K, V : Any> SerializerAwareValue<MutableMap<K, V>>.withDefault(defaultValueComputer: (K) -> V): SerializerAwareValue<NotNullMutableMap<K, V>> {
+        val origin = this
+
+        @Suppress("UNCHECKED_CAST")
+        return SerializableValue(
+            object : CompositeMapValue<K, V> {
+                private val instance = NotNullMutableMap(createDelegateInstance(origin, defaultValueComputer))
+
+                override var value: Map<K, V>
+                    get() = instance
+                    set(value) {
+                        origin.value = value as MutableMap<K, V> // erased cast
+                    }
+            } as Value<NotNullMutableMap<K, V>>, // erased cast
+            this.serializer
+        )
+    }
+
     /**
      * 创建一个代理对象, 当 [Map.get] 返回 `null` 时先调用 [defaultValueComputer] 并放入 [Map], 再返回调用的返回值
      */
+    @LowPriorityInOverloadResolution
     @JvmStatic
     @JvmName("withDefaultMap")
     public fun <K, V> SerializerAwareValue<MutableMap<K, V>>.withDefault(defaultValueComputer: (K) -> V): SerializerAwareValue<MutableMap<K, V>> {
@@ -95,24 +175,7 @@ public object PluginDataExtensions {
         @Suppress("UNCHECKED_CAST")
         return SerializableValue(
             object : CompositeMapValue<K, V> {
-                private val instance = object : MutableMap<K, V>, AbstractMap<K, V>() {
-                    override val entries: MutableSet<MutableMap.MutableEntry<K, V>> get() = origin.value.entries
-                    override val keys: MutableSet<K> get() = origin.value.keys
-                    override val values: MutableCollection<V> get() = origin.value.values
-                    override fun clear() = origin.value.clear()
-                    override fun putAll(from: Map<out K, V>) = origin.value.putAll(from)
-                    override fun remove(key: K): V? = origin.value.remove(key)
-                    override fun put(key: K, value: V): V? = origin.value.put(key, value)
-
-                    override fun get(key: K): V? {
-                        // the only difference
-                        val result = origin.value[key]
-                        if (result != null) return result
-                        put(key, defaultValueComputer(key))
-                        return origin.value[key]
-                    }
-                }
-
+                private val instance = createDelegateInstance(origin, defaultValueComputer)
                 override var value: Map<K, V>
                     get() = instance
                     set(value) {
@@ -123,6 +186,57 @@ public object PluginDataExtensions {
         )
     }
 
+    private fun <K, V> createDelegateInstance(
+        origin: SerializerAwareValue<MutableMap<K, V>>,
+        defaultValueComputer: (K) -> V
+    ): MutableMap<K, V> {
+        return object : MutableMap<K, V>, AbstractMap<K, V>() {
+            override val entries: MutableSet<MutableMap.MutableEntry<K, V>> get() = origin.value.entries
+            override val keys: MutableSet<K> get() = origin.value.keys
+            override val values: MutableCollection<V> get() = origin.value.values
+            override fun clear() = origin.value.clear()
+            override fun putAll(from: Map<out K, V>) = origin.value.putAll(from)
+            override fun remove(key: K): V? = origin.value.remove(key)
+            override fun put(key: K, value: V): V? = origin.value.put(key, value)
+
+            override fun get(key: K): V? {
+                // the only difference
+                val result = origin.value[key]
+                if (result != null) return result
+                put(key, defaultValueComputer(key))
+                return origin.value[key]
+            }
+        }
+    }
+
+
+    /**
+     * 替换 [MutableMap] 的 key
+     */
+    @JvmName("mapKeysNotNull")
+    @JvmStatic
+    public fun <OldK, NewK, V : Any> SerializerAwareValue<NotNullMutableMap<OldK, V>>.mapKeys(
+        oldToNew: (OldK) -> NewK,
+        newToOld: (NewK) -> OldK,
+    ): SerializerAwareValue<NotNullMutableMap<NewK, V>> {
+        val origin = this
+
+        @Suppress("UNCHECKED_CAST")
+        return SerializableValue(
+            object : CompositeMapValue<NewK, V> {
+                private val instance =
+                    NotNullMutableMap(ShadowMap({ origin.value }, oldToNew, newToOld, { it }, { it }))
+
+                override var value: Map<NewK, V>
+                    get() = instance
+                    set(value) {
+                        origin.value =
+                            value.mapKeysTo(NotNullMutableMap(LinkedHashMap())) { it.key.let(newToOld) } // erased cast
+                    }
+            } as Value<NotNullMutableMap<NewK, V>>, // erased cast
+            this.serializer
+        )
+    }
 
     /**
      * 替换 [MutableMap] 的 key
@@ -177,4 +291,72 @@ public object PluginDataExtensions {
             this.serializer
         )
     }
-}
\ No newline at end of file
+
+    /**
+     * 替换 [Map] 的 key
+     */
+    @JvmName("mapKeysImmutableNotNull")
+    @JvmStatic
+    public fun <OldK, NewK, V : Any> SerializerAwareValue<NotNullMap<OldK, V>>.mapKeys(
+        oldToNew: (OldK) -> NewK,
+        newToOld: (NewK) -> OldK,
+    ): SerializerAwareValue<NotNullMap<NewK, V>> {
+        val origin = this
+
+        @Suppress("UNCHECKED_CAST")
+        return SerializableValue(
+            object : CompositeMapValue<NewK, V> {
+                // casting Map to MutableMap is OK here, as we don't call mutable functions
+                private val instance =
+                    NotNullMap(ShadowMap({ origin.value as MutableMap<OldK, V> }, oldToNew, newToOld, { it }, { it }))
+
+                override var value: Map<NewK, V>
+                    get() = instance
+                    set(value) {
+                        origin.value =
+                            value.mapKeysTo(NotNullMutableMap(LinkedHashMap())) { it.key.let(newToOld) } // erased cast
+                    }
+            } as Value<NotNullMap<NewK, V>>, // erased cast
+            this.serializer
+        )
+    }
+}
+
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diff --git a/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/internal/data/builtins/BotManagerImpl.kt b/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/internal/data/builtins/BotManagerImpl.kt
index 0cdf45731..3abac0c9a 100644
--- a/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/internal/data/builtins/BotManagerImpl.kt
+++ b/backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/internal/data/builtins/BotManagerImpl.kt
@@ -44,8 +44,10 @@ internal object ManagersConfig : AutoSavePluginConfig() {
         管理员列表
     """
     )
-    private val managers by value<MutableMap<Long, MutableSet<Long>>>().withEmptyDefault()
-        .mapKeys(Bot::getInstance, Bot::id)
+    private val managers
+            by value<MutableMap<Long, MutableSet<Long>>>()
+                .withEmptyDefault()
+                .mapKeys(Bot::getInstance, Bot::id)
 
-    internal operator fun get(bot: Bot): MutableSet<Long> = managers[bot]!!
+    internal operator fun get(bot: Bot): MutableSet<Long> = managers[bot]
 }
\ No newline at end of file