Autofuzz generates invalid code for multi-dimensional array

[Marcono1234]

Description

Originally mentioned in #1024 (comment)

Autofuzz generates invalid code for multi-dimensional arrays such as int[][]. The Jazzer code uses Class#getName during code generation, however for arrays that uses the JVM type descriptor (e.g. [I), which is not valid in the generated Java code:

jazzer/src/main/java/com/code_intelligence/jazzer/autofuzz/Meta.java

Line 499 in c6296b8

String.format("new %s[]{", type.getComponentType().getName()), ", ", "}");

This could be solved by using Class#getTypeName which returns the desired format, however its documentation makes no guarantees about the output. So it might be safer to create a custom method which produces the desired type string.

Reproduction steps

1. Create a dummy Java class which takes a multi-dimensional array as input

   package example;
   
   public class Test {
       public Test(int[][] i) {
           if (i != null && i.length > 3) throw new RuntimeException();
       }
   }

2. Compile that file and package the compiled file (example/Test.class) in a JAR (e.g. example.jar)
3. Run Autofuzz

   ./jazzer --cp=example.jar --autofuzz="example.Test::new"

   ℹ️ This should detect a crash and generate a reproducer file Crash_....java
4. Inspect the reproducer file Crash_....java
   ❌ Bug: The generated reproducer contains invalid Java code new example.Test(new [I[]{...}); (note the [I)