From f60f37c36290bdfd05f3e810b0cec4187b15632a Mon Sep 17 00:00:00 2001
From: Mats Sibelius <sibelium@gmail.com>
Date: Mon, 8 Feb 2021 20:26:11 +0200
Subject: [PATCH] Fix case where mergeComplexNumberFormatMasks would get stuck
 in endless-loop (#1793)

* Fix case where mergeComplexNumberFormatMasks would get stuck in endless-loop if $numbers had many decimals
---
 src/PhpSpreadsheet/Style/NumberFormat.php |  8 +++++---
 tests/data/Style/NumberFormat.php         | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/PhpSpreadsheet/Style/NumberFormat.php b/src/PhpSpreadsheet/Style/NumberFormat.php
index 9a2549bc..a96d2ac3 100644
--- a/src/PhpSpreadsheet/Style/NumberFormat.php
+++ b/src/PhpSpreadsheet/Style/NumberFormat.php
@@ -563,9 +563,11 @@ class NumberFormat extends Supervisor
 
         do {
             $tempMask = array_pop($masks);
-            $postDecimalMasks[] = $tempMask;
-            $decimalCount -= strlen($tempMask);
-        } while ($decimalCount > 0);
+            if ($tempMask !== null) {
+                $postDecimalMasks[] = $tempMask;
+                $decimalCount -= strlen($tempMask);
+            }
+        } while ($tempMask !== null && $decimalCount > 0);
 
         return [
             implode('.', $masks),
diff --git a/tests/data/Style/NumberFormat.php b/tests/data/Style/NumberFormat.php
index 12aec1d3..81bb90ae 100644
--- a/tests/data/Style/NumberFormat.php
+++ b/tests/data/Style/NumberFormat.php
@@ -362,4 +362,24 @@ return [
         25,
         '[Green][<>25]"<>25 green";[Red]"else red"',
     ],
+    [
+        'pfx. 25.00',
+        25,
+        '"pfx." 0.00;"pfx." -0.00;"pfx." 0.00;',
+    ],
+    [
+        'pfx. 25.20',
+        25.2,
+        '"pfx." 0.00;"pfx." -0.00;"pfx." 0.00;',
+    ],
+    [
+        'pfx. -25.20',
+        -25.2,
+        '"pfx." 0.00;"pfx." -0.00;"pfx." 0.00;',
+    ],
+    [
+        'pfx. 25.26',
+        25.255555555555555,
+        '"pfx." 0.00;"pfx." -0.00;"pfx." 0.00;',
+    ],
 ];