From 2bd40b4c9c18562c7e082b972a39d005d1a1cc2c Mon Sep 17 00:00:00 2001
From: Sergey Minakov <naithar@icloud.com>
Date: Fri, 30 Apr 2021 11:40:12 +0300
Subject: [PATCH] [iOS] Nonnegative start index for virtual keyboard range

(cherry picked from commit 275772818ddc6b03cee4b72435828dca01b291e8)
---
 platform/iphone/keyboard_input_view.mm | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/platform/iphone/keyboard_input_view.mm b/platform/iphone/keyboard_input_view.mm
index abf9cae7730..a7834cabef1 100644
--- a/platform/iphone/keyboard_input_view.mm
+++ b/platform/iphone/keyboard_input_view.mm
@@ -87,13 +87,15 @@
 	self.text = existingString;
 	self.previousText = existingString;
 
+	NSInteger safeStartIndex = MAX(start, 0);
+
 	NSRange textRange;
 
 	// Either a simple cursor or a selection.
 	if (end > 0) {
-		textRange = NSMakeRange(start, end - start);
+		textRange = NSMakeRange(safeStartIndex, end - start);
 	} else {
-		textRange = NSMakeRange(start, 0);
+		textRange = NSMakeRange(safeStartIndex, 0);
 	}
 
 	self.selectedRange = textRange;