From 50808563167d680934ef117b3fead4440ce307a1 Mon Sep 17 00:00:00 2001
From: Pavel Zhulidov <96257569+PavelZul@users.noreply.github.com>
Date: Thu, 10 Apr 2025 00:03:36 +0400
Subject: [PATCH] Update Sum.php

We have a cell in the example.xlsx sheet containing a total sum as a formula:
E1 = IF(SUM(A1:B1) = SUM(C1:D1), "true", "false"), where:

A1 = 1.1,

B1 = 2.7,

C1 = 1.8,

D1 = 2.

We expect the calculation result to be E1 = "true", but instead, we get E1 = "false" because in PHP, the addition yields:

1.1 + 2.7 = 3.8000000000000003,

1.8 + 2 = 3.8.

The idea of the fork is to accept an input parameter specifying the number of decimal places and round the final sum to that precision before comparison.

Additional Notes:
This issue arises due to floating-point precision errors in programming languages like PHP.

A possible solution is to use rounding (e.g., round(SUM(A1:B1), N) == round(SUM(C1:D1), N) where N is the desired decimal precision).
---
 src/PhpSpreadsheet/Calculation/MathTrig/Sum.php | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php b/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php
index f939d9e747..e32f63fe68 100644
--- a/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php
+++ b/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php
@@ -47,12 +47,19 @@ public static function sumIgnoringStrings(mixed ...$args): float|int|string
      */
     public static function sumErroringStrings(mixed ...$args): float|int|string|array
     {
-        $returnValue = 0;
+        $returnValue = $maxDecimals = 0;
         // Loop through the arguments
         $aArgs = Functions::flattenArrayIndexed($args);
         foreach ($aArgs as $k => $arg) {
             // Is it a numeric value?
             if (is_numeric($arg)) {
+                // We count the number of signs after aim
+                $parts = explode('.', (string)$arg);
+                if (isset($parts[1])) {
+                    $decimals = strlen(rtrim($parts[1], '0'));
+                    $maxDecimals = max($maxDecimals, $decimals);
+                }
+                
                 $returnValue += $arg;
             } elseif (is_bool($arg)) {
                 $returnValue += (int) $arg;
@@ -64,7 +71,10 @@ public static function sumErroringStrings(mixed ...$args): float|int|string|arra
             }
         }
 
-        return $returnValue;
+        return $maxDecimals
+            ? round($returnValue, $maxDecimals)
+            : $returnValue;
+
     }
 
     /**