From 0ec2d526f35374dc0366024f8bb62aac4db1fd8d Mon Sep 17 00:00:00 2001
From: Mark Davis <davism@meta.com>
Date: Fri, 25 Oct 2024 12:55:13 -0700
Subject: [PATCH] Disable automatic async conversion for IGListAdapter APIs

Summary:
Threads has now run into multiple instances of device-only crashes resulting from usage of automatically converted Swift async versions of `performUpdates(animated:)` and `reloadData()`.

See D64428846, D64876801.

The crashes appear to stem from the opaque, automatically generated async methodology:

```
objc completion handler block implementation for escaping callee_unowned convention(block) (unowned Bool) -> () with result type Bool
```

Our `IGListKit` infra assuming ownership of these `callee_unowned` blocks seems to be problematic: the block can be released/nil'd, and our downstream [`[-[IGListReloadTransaction _executeCompletionBlocks:]`](https://www.internalfb.com/intern/logview/redirect/?filename=IGListReloadTransaction.m&line=82&repo=fbsource&revision=c1e4b4a34ff90e4785983b260f10543af6536215&build=655525612) execution then crashes.

Given this incompatibility with automatic conversion, here I propose:
1. marking the relevant `IGListAdapter.h` APIs with `NS_SWIFT_DISABLE_ASYNC`
2. providing manual async APIs in a new `IGListAdapter+Async.swift` extension hosted in `IGListSwiftKit` that existing callers can now make use of.

Differential Revision: D64881920

fbshipit-source-id: b15a5141a79491c1871b92f4f84a0c29b6045ee0
---
 Source/IGListKit/IGListAdapter.h              |  4 +-
 .../IGListSwiftKit/IGListAdapter+Async.swift  | 39 +++++++++++++++++++
 2 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 Source/IGListSwiftKit/IGListAdapter+Async.swift

diff --git a/Source/IGListKit/IGListAdapter.h b/Source/IGListKit/IGListAdapter.h
index 1e00d190e..dcf50f469 100644
--- a/Source/IGListKit/IGListAdapter.h
+++ b/Source/IGListKit/IGListAdapter.h
@@ -143,7 +143,7 @@ NS_SWIFT_NAME(ListAdapter)
  @param animated A flag indicating if the transition should be animated.
  @param completion The block to execute when the updates complete.
  */
-- (void)performUpdatesAnimated:(BOOL)animated completion:(nullable IGListUpdaterCompletion)completion;
+- (void)performUpdatesAnimated:(BOOL)animated completion:(nullable IGListUpdaterCompletion)completion NS_SWIFT_DISABLE_ASYNC;
 
 /**
  Perform an immediate reload of the data in the data source, discarding the old objects.
@@ -153,7 +153,7 @@ NS_SWIFT_NAME(ListAdapter)
  @warning Do not use this method to update without animations as it can be very expensive to teardown and rebuild all
  section controllers. Use `-[IGListAdapter performUpdatesAnimated:completion]` instead.
  */
-- (void)reloadDataWithCompletion:(nullable IGListUpdaterCompletion)completion;
+- (void)reloadDataWithCompletion:(nullable IGListUpdaterCompletion)completion NS_SWIFT_DISABLE_ASYNC;
 
 /**
  Reload the list for only the specified objects.
diff --git a/Source/IGListSwiftKit/IGListAdapter+Async.swift b/Source/IGListSwiftKit/IGListAdapter+Async.swift
new file mode 100644
index 000000000..c1a4b2888
--- /dev/null
+++ b/Source/IGListSwiftKit/IGListAdapter+Async.swift
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import IGListKit
+
+public extension ListAdapter {
+    /// Perform an update from the previous state of the data source. This is analogous to calling
+    /// `UICollectionView.performBatchUpdates(_:completion:)`.
+    ///
+    /// - Parameter animated: A flag indicating if the transition should be animated.
+    /// - Returns: `true` if the update animations completed successfully; otherwise `false`.
+    @discardableResult
+    func performUpdates(animated: Bool) async -> Bool {
+        return await withCheckedContinuation { continuation in
+            performUpdates(animated: animated) { finished in
+                continuation.resume(returning: finished)
+            }
+        }
+    }
+
+    /// Perform an immediate reload of the data in the data source, discarding the old objects.
+    ///
+    /// - Returns: `true` if the update animations completed successfully; otherwise `false`.
+    ///
+    /// @warning Do not use this method to update without animations as it can be very expensive to teardown and rebuild all
+    /// section controllers. Use `performUpdates(animated:) async` instead.
+    @discardableResult
+    func reloadData() async -> Bool {
+        return await withCheckedContinuation { continuation in
+            reloadData { finished in
+                continuation.resume(returning: finished)
+            }
+        }
+    }
+}