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Large arrays (~100+ elements) are not properly typed

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#68 0 comments 0 reactions 1 assignee View on GitHub

@Jonathing is already working on this.

Since Jan 14, 2025.

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Description

This is actually a Nashorn bug, but I'd like to workaround it in CoreMods 5.3. Essentially, large arrays (either created with [] or with varargs) are not converted to the required type, but rather to Object[]. This is a problem particularly for ASMAPI.listOf(), which uses a varargs signature of ([Lorg/objectweb/asm/tree/AbstractInsnNode;). When the coremod script is evaluated by Nashorn, the script fails with a ClassCastException: cannot cast [Ljava/lang/Object;] to org/objectweb/asm/tree/AbstractInsnNode.

Workarounds

The easiest way to workaround this is to manually add each node to a list. For example:

const list = ASMAPI.listOf();
list.add(node1);
list.add(node2);
// ...

However, another workaround is to use Java.to() to convert the entire array into your desired type. For example:

method.instructions = ASMAPI.listOf(Java.to([
    // ...
], Java.type('org.objectweb.asm.tree.AbstractInsnNode[]')));

Solution(?)

A solution to workaround this in CoreMods would be to create a sister method ASMAPI.listOf(Object... nodes) which accepts varargs object. Though, it might have a performance impact due to needing to cast each node to AbstractInsnNode. We can realistically skip the instanceof check since coremods should never attempt to add other objects that aren't nodes to an InsnList.

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Java
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