From 30f0e1843e374c302d189fa5328e69d21efe679a Mon Sep 17 00:00:00 2001
From: LynithDev <61880709+LynithDev@users.noreply.github.com>
Date: Thu, 1 Oct 2026 22:42:25 +0200
Subject: [PATCH] chore: add JVM argument to improve vector operations on Java
 21+ (#901)

---
 packages/oneclient_mc/src/arguments.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/oneclient_mc/src/arguments.rs b/packages/oneclient_mc/src/arguments.rs
index 1e7936cb..5b91da4c 100644
--- a/packages/oneclient_mc/src/arguments.rs
+++ b/packages/oneclient_mc/src/arguments.rs
@@ -64,6 +64,10 @@ pub fn java_arguments(
 
     parsed.extend(performance_flags(java_major, java_arch, mem_max, &custom));
 
+    if java_major >= 21 {
+        parsed.push("--add-modules=jdk.incubator.vector".to_string());
+    }
+
     parsed.push(format!("-Xmx{mem_max}M"));
     parsed.extend(custom);
 
@@ -893,7 +897,7 @@ mod tests {
         let cp = classpaths(&dir, &libraries, &client, "x86", false).unwrap();
 
         assert!(
-            !cp.contains("asm-all"),
+            !cp.contains("asm-all-4.1.jar"),
             "fabric aborts on two copies of org/objectweb/asm/ClassReader.class: {cp}"
         );
         assert!(cp.contains("asm-9.10.1.jar"), "{cp}");