Eventbus: Illegal onEvent method - ProGuard

[DavidEdwards]

I am receiving this error:

Illegal onEvent method, check for typos

The error appears to be caused by a method name changing in my compile process by ProGuard. Here is a sample of the log I created to test:

methodName=onEvent
modifierString=
methodName=onEvent$3884d48a
modifierString=$3884d48a
skipMethodVerificationForClasses={}

The solution is to check for the $ character at the start of the modifierString.

This diff solves the issue:

@@ -91,7 +91,7 @@ class SubscriberMethodFinder {
                             } else if (modifierString.equals("Async")) {
                                 threadMode = ThreadMode.Async;
                             } else {
-                                if (skipMethodVerificationForClasses.containsKey(clazz)) {
+                                if (skipMethodVerificationForClasses.containsKey(clazz) || modifierString.startsWith("$")) {
                                     continue;
                                 } else {
                                     throw new EventBusException("Illegal onEvent method, check for typos: " + method);

[greenrobot]

Interesting. Can you detail how you got ProGuard to have such names? What was the original method name of the offending method?

[DavidEdwards]

Honestly, no. I just checked my ProGuard mapping file. The method signature
does not even exist in the project.
On Wed Dec 03 2014 at 4:12:21 PM greenrobot [email protected]
wrote:

Interesting. Can you detail how you got ProGuard to have such names?

—
Reply to this email directly or view it on GitHub
https://github.com/greenrobot/EventBus/issues/133#issuecomment-65423117.

[greenrobot]

Funny, which ProGuard version are you using?

[DavidEdwards]

Version 4.7

On Wed Dec 03 2014 at 4:18:40 PM greenrobot [email protected]
wrote:

Funny, which ProGuard version are you using?

—
Reply to this email directly or view it on GitHub
https://github.com/greenrobot/EventBus/issues/133#issuecomment-65424527.

[donhav]

I have a issue with pro guard, optimizing this class, both versions 5.1 and 4.7. If you turn on proguards "-optimizations code/removal/advanced: flag (Which you need to make -assumenosideeffects work so you can remove logging from your code) proguard removes the addition of the subscriberMethod in SubscriberMethodFinder.

IE: it turns this

subscriberMethods.add(new SubscriberMethod(method, threadMode, eventType));

into this

new SubscriberMethod(localMethod, localThreadMode, localClass);

So the eventBus never finds any onEvent methods. This would seem to be a problem in proguard.

[vindaz]

I have the same problem, now I solved it by this:
change onEvent(SOMETHING EXTENDS OBJECT) to onEvent(android.os.Message )

the version of proguard is 5.1;

here is the error stack:
12-19 07:16:24.832 4126-4126/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
de.greenrobot.event.EventBusException: Illegal onEvent method, check for typos: public void com.MYPACKAGE.c.a.onEvent$4b6f2907(com.b.a.b.c)
at de.greenrobot.event.SubscriberMethodFinder.findSubscriberMethods(SubscriberMethodFinder.java:95)
at de.greenrobot.event.EventBus.register(EventBus.java:163)
at de.greenrobot.event.EventBus.register(EventBus.java:133)
at com.MYPACKAGE.c.a.onResume(BaseFragment.java:88)

and in the mapping file:
65:72:void onEvent$4b6f2907(com.google.gson.internal.ConstructorConstructor$1) -> onEvent$4b6f2907

[bluef]

We met the same issue, and we searched the mapping.txt and found one line like this:

448:462:void onEvent$6f60fb76(android.support.v7.widget.RecyclerView$SmoothScroller$Action) -> onEvent$6f60fb76

RecyclerView introduce a method named onEvent$6f60fb76 which breaks SubscriberMethodFinder.findSubscriberMethods. @DavidEdwards 's way is a good way to fix it.

[sdeff]

I had an similar issue and I contacted the creator of ProGuard/DexGuard and he sent me a 'workaround' for this.

Just add:
-keepclassmembers,includedescriptorclasses class ** { public void onEvent*(**); }

To your config file to prevent ProGuard/DexGuard's optimization step to add a suffix to the method name.

[jayzhou215]

@DavidEdwards no, you cannot fix this issus by this. you just hide the bug, the method onEvent$() won't execute in logic if fix by this! If I wrote an onEvent() but it won't execute after proguard, this not what I want.
and final my solution is:

modifierString.equals("MainThread") --> modifierString.startWith("MainThread")
...
modifierString.equals("BackgroundThread") --> modifierString.startWith("BackgroundThread")
...
modifierString.equals("Async") --> modifierString.startWith("Async")


[jayzhou215]

@sdeff Your answer should be the right solution.

[cs-victor-nascimento]

Stumbled upon this recently. This should be in the wiki of the project.