Verify that ASM is only on the classpath once. (#965)

FabricMC · Aug 15, 2024 · 633f91a · 633f91a
1 parent 991d38d
commit 633f91a
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/src/main/java/net/fabricmc/loader/impl/launch/knot/Knot.java b/src/main/java/net/fabricmc/loader/impl/launch/knot/Knot.java
@@ -342,9 +342,6 @@ public static void main(String[] args) {
 
 	static {
 		LoaderUtil.verifyNotInTargetCl(Knot.class);
-
-		if (IS_DEVELOPMENT) {
-			LoaderUtil.verifyClasspath();
-		}
+		LoaderUtil.verifyClasspath();
 	}
 }
diff --git a/src/main/java/net/fabricmc/loader/impl/util/LoaderUtil.java b/src/main/java/net/fabricmc/loader/impl/util/LoaderUtil.java
@@ -58,12 +58,18 @@ public static void verifyNotInTargetCl(Class<?> cls) {
 
 	public static void verifyClasspath() {
 		try {
-			final List<URL> resources = Collections.list(LoaderUtil.class.getClassLoader().getResources("net/fabricmc/loader/api/FabricLoader.class"));
+			List<URL> resources = Collections.list(LoaderUtil.class.getClassLoader().getResources("net/fabricmc/loader/api/FabricLoader.class"));
 
 			if (resources.size() != 1) {
 				// This usually happens when fabric loader has been added to the classpath more than once.
 				throw new IllegalStateException("duplicate fabric loader classes found on classpath: " + resources.stream().map(URL::toString).collect(Collectors.joining(", ")));
 			}
+
+			resources = Collections.list(LoaderUtil.class.getClassLoader().getResources("org/objectweb/asm/ClassReader.class"));
+
+			if (resources.size() != 1) {
+				throw new IllegalStateException("duplicate ASM classes found on classpath: " + resources.stream().map(URL::toString).collect(Collectors.joining(", ")));
+			}
 		} catch (IOException e) {
 			throw new UncheckedIOException("Failed to get resources", e);
 		}