From cf3a3bb0bd8d6c638c1ff4ab883eaf1cd4b223ee Mon Sep 17 00:00:00 2001
From: Luke Abby <luke@lukeabby.dev>
Date: Sat, 19 Oct 2024 16:38:46 -0700
Subject: [PATCH] Fix "Type of property circularly references itself in mapped
 type" errors

---
 .../client/data/abstract/client-document.d.mts   | 16 +++++++++++++---
 src/foundry/common/abstract/document.d.mts       |  2 +-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/foundry/client/data/abstract/client-document.d.mts b/src/foundry/client/data/abstract/client-document.d.mts
index 0d5311a0f..b5b47351c 100644
--- a/src/foundry/client/data/abstract/client-document.d.mts
+++ b/src/foundry/client/data/abstract/client-document.d.mts
@@ -554,11 +554,14 @@ declare global {
    * A mixin which extends each Document definition with specialized client-side behaviors.
    * This mixin defines the client-side interface for database operations and common document behaviors.
    */
-  // Note: Unlike most mixins, `ClientDocumentMixin` actually requires a specific constructor, the same as `Document`.
-  // This means that `BaseClass extends Document.AnyConstructor` would be too permissive.
+  // FIXME(LukeAbby): Unlike most mixins, `ClientDocumentMixin` actually requires a specific constructor, the same as `Document`.
+  // This means that `BaseClass extends Document.Internal.Constructor` is actually too permissive.
+  // However this easily leads to circularities.
+  //
+  // Note(LukeAbby): The seemingly redundant merging in of `AnyDocument` makes it easier for tsc to recognize that anything extending `ClientDocumentMixin` is also a document.
   function ClientDocumentMixin<BaseClass extends Document.Internal.Constructor>(
     Base: BaseClass,
-  ): Mixin<typeof ClientDocument<InstanceType<BaseClass>>, BaseClass>;
+  ): AnyDocument & Mixin<typeof ClientDocument<InstanceType<BaseClass>>, BaseClass>;
 
   namespace ClientDocument {
     interface SortOptions<T, SortKey extends string = "sort"> extends SortingHelpers.SortOptions<T, SortKey> {
@@ -645,6 +648,13 @@ declare namespace DropData {
   }
 }
 
+// This is yet another `AnyDocument` type.
+// It exists specifically because the `Document.AnyConstructor` type is too safe to be merged in with a mixin.
+// The `arg0: never, ...args: never[]` trick trips up the base constructor check and so this one with an actual `...args: any[]` one is used instead.
+declare class AnyDocument extends Document<any, any, any> {
+  constructor(...args: any[]);
+}
+
 type InternalData<T extends Document.Internal.Instance.Any> = DropData.Data<Document.Internal.Instance.Complete<T>>;
 
 interface FromDropDataOptions {
diff --git a/src/foundry/common/abstract/document.d.mts b/src/foundry/common/abstract/document.d.mts
index b07505aa7..501204b12 100644
--- a/src/foundry/common/abstract/document.d.mts
+++ b/src/foundry/common/abstract/document.d.mts
@@ -882,7 +882,7 @@ declare namespace Document {
 
   type ConfiguredClass<T extends { metadata: AnyMetadata }> = ConfiguredClassForName<T["metadata"]["name"]>;
 
-  type ConfiguredClassForName<Name extends Type> = ConfiguredDocuments[Name];
+  type ConfiguredClassForName<Name extends Type> = MakeConform<ConfiguredDocuments[Name], Document.AnyConstructor>;
 
   type SubTypesOf<T extends Type> =
     ConfiguredInstanceForName<T> extends { type: infer Types } ? Types : typeof foundry.CONST.BASE_DOCUMENT_TYPE;