From fa9e1f5b57b7ec7aec03091637e3dc1956d865d7 Mon Sep 17 00:00:00 2001
From: Jake Wharton <jw@squareup.com>
Date: Wed, 31 Jul 2024 13:34:01 -0400
Subject: [PATCH] Seal the protocol factory interface (#2215)

The only subtype should be the generated interface which is itself open to new subtypes.
---
 CHANGELOG.md                                           |  2 +-
 .../api/redwood-protocol-host.klib.api                 | 10 +++++-----
 .../app/cash/redwood/protocol/host/ProtocolFactory.kt  |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d4c380a38d..89c5b5aacf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,7 @@ New:
 - Introduce a `LoadingStrategy` interface to manage `LazyList` preloading.
 
 Changed:
-- Nothing yet!
+- `ProtocolFactory` interface is now sealed as arbitrary subtypes were never supported. Only schema-generated subtypes should be used.
 
 Fixed:
 - Nothing yet!
diff --git a/redwood-protocol-host/api/redwood-protocol-host.klib.api b/redwood-protocol-host/api/redwood-protocol-host.klib.api
index 327e90bef7..23ad9f283b 100644
--- a/redwood-protocol-host/api/redwood-protocol-host.klib.api
+++ b/redwood-protocol-host/api/redwood-protocol-host.klib.api
@@ -12,11 +12,6 @@ abstract interface <#A: kotlin/Any> app.cash.redwood.protocol.host/GeneratedProt
     abstract fun widgetChildren(app.cash.redwood.protocol/WidgetTag): kotlin.collections/List<app.cash.redwood.protocol/ChildrenTag> // app.cash.redwood.protocol.host/GeneratedProtocolFactory.widgetChildren|widgetChildren(app.cash.redwood.protocol.WidgetTag){}[0]
 }
 
-abstract interface <#A: kotlin/Any> app.cash.redwood.protocol.host/ProtocolFactory { // app.cash.redwood.protocol.host/ProtocolFactory|null[0]
-    abstract val widgetSystem // app.cash.redwood.protocol.host/ProtocolFactory.widgetSystem|{}widgetSystem[0]
-        abstract fun <get-widgetSystem>(): app.cash.redwood.widget/WidgetSystem<#A> // app.cash.redwood.protocol.host/ProtocolFactory.widgetSystem.<get-widgetSystem>|<get-widgetSystem>(){}[0]
-}
-
 abstract interface app.cash.redwood.protocol.host/ProtocolMismatchHandler { // app.cash.redwood.protocol.host/ProtocolMismatchHandler|null[0]
     abstract fun onUnknownChildren(app.cash.redwood.protocol/WidgetTag, app.cash.redwood.protocol/ChildrenTag) // app.cash.redwood.protocol.host/ProtocolMismatchHandler.onUnknownChildren|onUnknownChildren(app.cash.redwood.protocol.WidgetTag;app.cash.redwood.protocol.ChildrenTag){}[0]
     abstract fun onUnknownModifier(app.cash.redwood.protocol/ModifierTag) // app.cash.redwood.protocol.host/ProtocolMismatchHandler.onUnknownModifier|onUnknownModifier(app.cash.redwood.protocol.ModifierTag){}[0]
@@ -29,6 +24,11 @@ abstract interface app.cash.redwood.protocol.host/ProtocolMismatchHandler { // a
     }
 }
 
+sealed interface <#A: kotlin/Any> app.cash.redwood.protocol.host/ProtocolFactory { // app.cash.redwood.protocol.host/ProtocolFactory|null[0]
+    abstract val widgetSystem // app.cash.redwood.protocol.host/ProtocolFactory.widgetSystem|{}widgetSystem[0]
+        abstract fun <get-widgetSystem>(): app.cash.redwood.widget/WidgetSystem<#A> // app.cash.redwood.protocol.host/ProtocolFactory.widgetSystem.<get-widgetSystem>|<get-widgetSystem>(){}[0]
+}
+
 abstract class <#A: kotlin/Any> app.cash.redwood.protocol.host/ProtocolNode { // app.cash.redwood.protocol.host/ProtocolNode|null[0]
     constructor <init>(app.cash.redwood.protocol/Id, app.cash.redwood.protocol/WidgetTag) // app.cash.redwood.protocol.host/ProtocolNode.<init>|<init>(app.cash.redwood.protocol.Id;app.cash.redwood.protocol.WidgetTag){}[0]
 
diff --git a/redwood-protocol-host/src/commonMain/kotlin/app/cash/redwood/protocol/host/ProtocolFactory.kt b/redwood-protocol-host/src/commonMain/kotlin/app/cash/redwood/protocol/host/ProtocolFactory.kt
index a5af9bb50a..feb605ee0c 100644
--- a/redwood-protocol-host/src/commonMain/kotlin/app/cash/redwood/protocol/host/ProtocolFactory.kt
+++ b/redwood-protocol-host/src/commonMain/kotlin/app/cash/redwood/protocol/host/ProtocolFactory.kt
@@ -30,7 +30,7 @@ import kotlin.native.ObjCName
  * @see HostProtocolAdapter
  */
 @ObjCName("ProtocolFactory", exact = true)
-public interface ProtocolFactory<W : Any> {
+public sealed interface ProtocolFactory<W : Any> {
   public val widgetSystem: WidgetSystem<W>
 }