Add workaround for setupCIWorkspace not being sufficient

build.gradle

@@ -200,6 +200,57 @@ setupDecompWorkspace.dependsOn copySrg
 setupDevWorkspace.dependsOn copySrg
 project.tasks.idea.dependsOn copySrg
 
+
+import org.objectweb.asm.*
+
+import java.util.zip.ZipEntry
+import java.util.zip.ZipFile
+import java.util.zip.ZipOutputStream
+
+import static org.objectweb.asm.Opcodes.ASM5
+
+// MC binaries were complied with a java version that produces invalid class files under certain circumstances
+// This causes setupCIWorkspace to be insufficient for compiling.
+// Related JDK bug: https://bugs.openjdk.java.net/browse/JDK-8066725
+// As a workaround, to use setupCIWorkspace on Drone, we modify the bin jar in-place and remove all parameter annotations.
+// WARNING: This piece of code ignores any and all gradle conventions and will probably fail horribly when run outside
+// of a single-use environment (e.g. Drone). Use setupDecompWorkspace for normal use.
+tasks.deobfMcMCP.doLast {
+    println "Applying RuntimeInvisibleParameterAnnotations workaround..."
+    File jar = getOutJar()
+    File tmp = new File((File) getTemporaryDir(), "workaround.jar")
+    tmp.withOutputStream {
+        new ZipOutputStream(it).withStream { dst ->
+            new ZipFile(jar).withCloseable { src ->
+                src.entries().each {
+                    if (it.name.startsWith("net/minecraft/") && it.name.endsWith(".class")) {
+                        def cw = new ClassWriter(0)
+                        def cv = new ClassVisitor(ASM5, cw) {
+                            @Override
+                            MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
+                                return new MethodVisitor(ASM5, cv.visitMethod(access, name, desc, signature, exceptions)) {
+                                    @Override
+                                    AnnotationVisitor visitParameterAnnotation(int parameter, String pdesc, boolean visible) {
+                                        return null // Strip all parameter annotations
+                                    }
+                                }
+                            }
+                        }
+                        new ClassReader(src.getInputStream(it)).accept(cv, 0)
+                        dst.putNextEntry(new ZipEntry(it.name))
+                        dst.write(cw.toByteArray())
+                    } else {
+                        dst.putNextEntry(it)
+                        dst.write(src.getInputStream(it).bytes)
+                    }
+                }
+            }
+        }
+    }
+    jar.delete()
+    tmp.renameTo(jar)
+}
+
 def generateVersionsJson() {
     // List all tags
     def stdout = new ByteArrayOutputStream()