From 9ea7957958c3f7acdaec6309117af61072986818 Mon Sep 17 00:00:00 2001
From: Valentin Shergin <shergin@fb.com>
Date: Tue, 8 May 2018 18:50:19 -0700
Subject: [PATCH] Fabric: Do not crash in attempt to mount layout-only
 components

Summary: We do not have a clear strategy how to deal with layout-only (view-less) components. Even if this particular solution is not so fancy, it prevents crashing during text rendering.

Reviewed By: mdvacca

Differential Revision: D7785885

fbshipit-source-id: f3ed8988aa2b41349fd1693c2a7f8c9368daee43
---
 React/Fabric/Mounting/MountItems/RCTDeleteMountItem.mm | 5 +++++
 React/Fabric/Mounting/MountItems/RCTInsertMountItem.mm | 4 ++++
 React/Fabric/Mounting/MountItems/RCTRemoveMountItem.mm | 4 ++++
 3 files changed, 13 insertions(+)

diff --git a/React/Fabric/Mounting/MountItems/RCTDeleteMountItem.mm b/React/Fabric/Mounting/MountItems/RCTDeleteMountItem.mm
index 99909f450..ed4a884e4 100644
--- a/React/Fabric/Mounting/MountItems/RCTDeleteMountItem.mm
+++ b/React/Fabric/Mounting/MountItems/RCTDeleteMountItem.mm
@@ -28,6 +28,11 @@
 - (void)executeWithRegistry:(RCTComponentViewRegistry *)registry
 {
   UIView<RCTComponentViewProtocol> *componentView = [registry componentViewByTag:_tag];
+
+  if (componentView == nil) {
+    return;
+  }
+
   [registry enqueueComponentViewWithName:_componentName tag:_tag componentView:componentView];
 }
 
diff --git a/React/Fabric/Mounting/MountItems/RCTInsertMountItem.mm b/React/Fabric/Mounting/MountItems/RCTInsertMountItem.mm
index f714cb0a7..740718b96 100644
--- a/React/Fabric/Mounting/MountItems/RCTInsertMountItem.mm
+++ b/React/Fabric/Mounting/MountItems/RCTInsertMountItem.mm
@@ -33,6 +33,10 @@
   UIView<RCTComponentViewProtocol> *childComponentView = [registry componentViewByTag:_childTag];
   UIView<RCTComponentViewProtocol> *parentComponentView = [registry componentViewByTag:_parentTag];
 
+  if (childComponentView == nil || parentComponentView == nil) {
+    return;
+  }
+
   [parentComponentView mountChildComponentView:childComponentView
                                          index:_index];
 }
diff --git a/React/Fabric/Mounting/MountItems/RCTRemoveMountItem.mm b/React/Fabric/Mounting/MountItems/RCTRemoveMountItem.mm
index d46b936dd..3279b9394 100644
--- a/React/Fabric/Mounting/MountItems/RCTRemoveMountItem.mm
+++ b/React/Fabric/Mounting/MountItems/RCTRemoveMountItem.mm
@@ -33,6 +33,10 @@
   UIView<RCTComponentViewProtocol> *childComponentView = [registry componentViewByTag:_childTag];
   UIView<RCTComponentViewProtocol> *parentComponentView = [registry componentViewByTag:_parentTag];
 
+  if (childComponentView == nil || parentComponentView == nil) {
+    return;
+  }
+
   [parentComponentView unmountChildComponentView:childComponentView
                                            index:_index];
 }