Disable yaml duplicate keys warning by default

Author: Dreeam-qwq

leaf-api/paper-patches/features/0021-Disable-yaml-duplicate-keys-warning-by-default.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Dreeam <[email protected]>
+Date: Tue, 16 Dec 2025 04:44:10 -0500
+Subject: [PATCH] Disable yaml duplicate keys warning by default
+
+Disable Yaml's warnOnDuplicateKeys by deafault to
+follow the original behavior
+
+It's just a warning output introduced since snakeyaml 2.4,
+See https://github.com/snakeyaml/snakeyaml/commit/b16f9485f33136fb30f8472f3ccf0209707c023e
+
+The comment of LoaderOptions#setWarnOnDuplicateKeys is
+actually misleading, since this warnOnDuplicateKeys option
+is enabled by default when creates new Yaml instance
+
+
+diff --git a/src/main/java/org/bukkit/configuration/file/YamlConfiguration.java b/src/main/java/org/bukkit/configuration/file/YamlConfiguration.java
+index ed81e850b22b83ac872707daf3c7d5d0cac6176b..c4fab5b8b3eb5f52c7ec88ed70fc85996cc04554 100644
+--- a/src/main/java/org/bukkit/configuration/file/YamlConfiguration.java
++++ b/src/main/java/org/bukkit/configuration/file/YamlConfiguration.java
+@@ -62,6 +62,7 @@ public class YamlConfiguration extends FileConfiguration {
+         yamlLoaderOptions.setMaxAliasesForCollections(Integer.MAX_VALUE); // SPIGOT-5881: Not ideal, but was default pre SnakeYAML 1.26
+         yamlLoaderOptions.setCodePointLimit(Integer.MAX_VALUE); // SPIGOT-7161: Not ideal, but was default pre SnakeYAML 1.32
+         yamlLoaderOptions.setNestingDepthLimit(100); // SPIGOT-7906: The default limit (50) can be easily reached with nested bundles
++        yamlLoaderOptions.setWarnOnDuplicateKeys(false); // Leaf - Disable yaml duplicate keys warning by default
+ 
+         constructor = new YamlConstructor(yamlLoaderOptions);
+         representer = new YamlRepresenter(yamlDumperOptions);