fix(config): use SnakeYAML default ctor (2.x compatible) for existing-config load

core/build.gradle.kts

@@ -33,8 +33,11 @@ dependencies {
     testImplementation("io.netty", "netty-transport", Versions.nettyVersion)
     testImplementation("io.netty", "netty-codec", Versions.nettyVersion)
     testImplementation("com.squareup.okhttp3:mockwebserver:4.9.3")
-    // Parses the release workflows in the release verification tests.
-    testImplementation("org.yaml:snakeyaml:1.27")
+    // Parses the release workflows in the release verification tests. 2.x on purpose: Velocity
+    // 4.x supplies SnakeYAML 2.x at runtime (via Configurate), where the no-arg SafeConstructor
+    // constructor no longer exists - ConfigLoaderTest's regression guard for the 0.15.10
+    // NoSuchMethodError must run against the 2.x API the platform actually provides.
+    testImplementation("org.yaml:snakeyaml:2.2")
     testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }
 

core/src/main/java/com/minekube/connect/config/ConfigLoader.java

@@ -51,7 +51,6 @@
 import org.geysermc.configutils.file.template.ResourceTemplateReader;
 import org.geysermc.configutils.updater.change.Changes;
 import org.yaml.snakeyaml.Yaml;
-import org.yaml.snakeyaml.constructor.SafeConstructor;
 
 @Getter
 @RequiredArgsConstructor
@@ -71,7 +70,9 @@ private static void fixPlaceholderIssue(Path path) throws IOException {
 
     private static boolean hasBedrockIdentitySection(Path path) throws IOException {
         try (Reader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8)) {
-            Object document = new Yaml(new SafeConstructor()).load(reader);
+            // Default ctor: delegates to SafeConstructor in both SnakeYAML 1.x and 2.x (the
+            // no-arg SafeConstructor ctor was removed in 2.0, which Velocity provides at runtime).
+            Object document = new Yaml().load(reader);
             return document instanceof Map<?, ?> map && map.containsKey("bedrock-identity");
         }
     }

core/src/test/java/com/minekube/connect/config/ConfigLoaderTest.java

@@ -147,6 +147,33 @@ void loginReassertDefaultsToOnAndPropertiesOnly() throws Exception {
                 "restoring the UUID needs an operator-side prerequisite, so it must be opt-in");
     }
 
+    /**
+     * Velocity 4.x provides SnakeYAML 2.x at runtime (through Configurate), where the no-arg
+     * {@code SafeConstructor()} constructor was removed. 0.15.10 (PR #157) loaded an existing
+     * config.yml with {@code new Yaml(new SafeConstructor())}, so every existing-config load on
+     * Velocity crashed with NoSuchMethodError. The core test dependency pins SnakeYAML 2.x to
+     * reproduce that platform classpath; loading a legacy config must apply the safe Minekube
+     * defaults instead of crashing.
+     */
+    @Test
+    void legacyConfigLoadsOnSnakeYaml2xRuntimeClasspath() throws Exception {
+        Files.writeString(tempDir.resolve("config.yml"), String.join("\n",
+                "endpoint: codexp2p3",
+                "allow-offline-mode-players: false",
+                "metrics:",
+                "  disabled: true",
+                "  uuid: 00000000-0000-0000-0000-000000000000",
+                "config-version: 1",
+                ""));
+
+        ConnectConfig config = load(ConnectConfig.class);
+
+        assertEquals("warn", config.getBedrockIdentity().getEnforcement());
+        assertEquals(
+                "https://watch-connect.minekube.net/.well-known/minekube-connect/bedrock-identity-keys.json",
+                config.getBedrockIdentity().getMetadataUrl());
+    }
+
     /** Both halves are operator-controllable from the config file. */
     @Test
     void loadsLoginReassertOverrides() throws Exception {