From a198a4eef46bd83a1952f8413077e721e5102f9f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julius=20H=C3=A4rtl?= <jus@bitgrid.net>
Date: Mon, 27 Feb 2023 23:13:06 +0100
Subject: [PATCH] fix: Avoid mutating the due date when calculating days
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Signed-off-by: Julius Härtl <jus@bitgrid.net>
---
 lib/Db/Card.php | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/Db/Card.php b/lib/Db/Card.php
index 5a80ed35a..e36a9fb0c 100644
--- a/lib/Db/Card.php
+++ b/lib/Db/Card.php
@@ -159,16 +159,17 @@ class Card extends RelationalEntity {
 	}
 
 	public function getDaysUntilDue(): ?int {
-		$today = new DateTime();
-		$match_date = $this->getDuedate();
-		if ($match_date === null) {
+		if ($this->getDuedate() === null) {
 			return null;
 		}
 
+		$today = new DateTime();
 		$today->setTime(0, 0);
-		$match_date->setTime(0, 0);
 
-		$diff = $today->diff($match_date);
+		$matchDate = DateTime::createFromInterface($this->getDuedate());
+		$matchDate->setTime(0, 0);
+
+		$diff = $today->diff($matchDate);
 		return (int) $diff->format('%R%a'); // Extract days count in interval
 	}