From 1051e10732a6f4a4e76099506031e8cc8a06952e Mon Sep 17 00:00:00 2001
From: Joshua Ramon Enslin <joshua@museum-digital.de>
Date: Tue, 6 May 2025 22:32:00 +0200
Subject: [PATCH] Prevent ambigious splitting of [0-9]{4}-[0-9]{2}

---
 src/NodaTimeSplitter.php       | 6 ++++++
 tests/NodaTimeSplitterTest.php | 1 +
 2 files changed, 7 insertions(+)

diff --git a/src/NodaTimeSplitter.php b/src/NodaTimeSplitter.php
index 33c6e1c..8ab32bc 100644
--- a/src/NodaTimeSplitter.php
+++ b/src/NodaTimeSplitter.php
@@ -609,6 +609,12 @@ final class NodaTimeSplitter {
 
             // Assume the end is a month
             if (intval($month) < 12) {
+                // If the year is smaller than the second number, do not split, as either month
+                // or year may be meant
+                // Example: 1903-04
+                if (substr($datum, 2, 2) < 12) {
+                    return false;
+                }
                 return new NodaSplitTime($year, $year, $month);
             }
             else {
diff --git a/tests/NodaTimeSplitterTest.php b/tests/NodaTimeSplitterTest.php
index 405d827..82175df 100644
--- a/tests/NodaTimeSplitterTest.php
+++ b/tests/NodaTimeSplitterTest.php
@@ -604,6 +604,7 @@ final class NodaTimeSplitterTest extends TestCase {
             "13.13.2022",
             "2022-13-13",
             "40.10.2022",
+            "1903-04",
             "1903/04",
             "2022-10-40",
             "6;November 1978",