From 7659949d6515e7895b8e67b2777bbfd2ef8d5163 Mon Sep 17 00:00:00 2001
From: Andrew Clark <git@andrewclark.io>
Date: Tue, 8 Dec 2020 19:13:20 -0600
Subject: [PATCH] Clear `deletions` in `detachFiber` (#20401)

This was added in a later step of the refactor but since `deletions`
array already landed, clearing it should, too.

I think it's unlikely that this causes GC problems but worth
adding anyway.
---
 packages/react-reconciler/src/ReactFiberCommitWork.new.js | 1 +
 packages/react-reconciler/src/ReactFiberCommitWork.old.js | 1 +
 2 files changed, 2 insertions(+)

diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.new.js b/packages/react-reconciler/src/ReactFiberCommitWork.new.js
index a9c54d9c02e98..84a20638ef299 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.new.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.new.js
@@ -1074,6 +1074,7 @@ function detachFiberMutation(fiber: Fiber) {
   // and one of its descendants throws while unmounting a passive effect.
   fiber.alternate = null;
   fiber.child = null;
+  fiber.deletions = null;
   fiber.dependencies = null;
   fiber.firstEffect = null;
   fiber.lastEffect = null;
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.old.js b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
index c134ecccddbb9..94d137c99bdc2 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
@@ -1074,6 +1074,7 @@ function detachFiberMutation(fiber: Fiber) {
   // and one of its descendants throws while unmounting a passive effect.
   fiber.alternate = null;
   fiber.child = null;
+  fiber.deletions = null;
   fiber.dependencies = null;
   fiber.firstEffect = null;
   fiber.lastEffect = null;