From 09a624ef8e62e4c14acc53119d1575d11a96a967 Mon Sep 17 00:00:00 2001
From: Alexander Hofstede <alex@hofste.de>
Date: Mon, 16 Dec 2019 20:01:48 +0100
Subject: [PATCH] Avoid $previousValue if length is < 1

---
 src/Spout/Writer/XLSX/Manager/WorksheetManager.php | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/Spout/Writer/XLSX/Manager/WorksheetManager.php b/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
index ba682a5..abfc476 100644
--- a/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
+++ b/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
@@ -143,10 +143,12 @@ EOD;
         $sequence = [];
         foreach ($columns as $i) {
             $sequenceLength = count($sequence);
-            $previousValue = $sequence[$sequenceLength - 1];
-            if ($sequenceLength > 0 && $i !== $previousValue + 1) {
-                $this->setColumnWidthForRange($width, $sequence[0], $previousValue);
-                $sequence = [];
+            if ($sequenceLength > 0) {
+                $previousValue = $sequence[$sequenceLength - 1];
+                if ($i !== $previousValue + 1) {
+                    $this->setColumnWidthForRange($width, $sequence[0], $previousValue);
+                    $sequence = [];
+                }
             }
             $sequence[] = $i;
         }