java.lang.VerifyError: Bad return type

[sproctor]

This error only happens with Proguard 7.4.x. Adding -dontoptimize or reverting to 7.2.2 gets rid of the crash.

java.lang.VerifyError: Bad return type
Exception Details:
  Location:
    b/b/e/cb.a(Lkotlin/jvm/functions/Function0;)Lb/b/e/V; @18: areturn
  Reason:
    Type 'b/b/e/ct' (current frame, stack[0]) is not assignable to 'b/b/e/V' (from method signature)
  Current Frame:
    bci: @18
    flags: { }
    locals: { 'kotlin/jvm/functions/Function0' }
    stack: { 'b/b/e/ct' }
  Bytecode:
    0000000: 2a12 06b8 0016 bb00 0759 2a01 b700 11c0
    0000010: 000c b0                                

	at b.b.e.t.b(SourceFile:51531)
	at b.b.e.t.a(SourceFile:3236)
	at b.b.e.E.c(SourceFile:723)
	at b.b.e.bi.a(SourceFile:1071)
	at b.b.e.E.d(SourceFile:631)
	at b.b.e.E.a(SourceFile:617)
	at b.b.f.u.i.invokeSuspend(SourceFile:219)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:33)
	at kotlinx.coroutines.DispatchedTask.run(SourceFile:108)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)

Proguard 7.3.2 has a different error:

java.lang.VerifyError: Bad type on operand stack
Exception Details:
  Location:
    b/b/e/cg.a(Lkotlinx/coroutines/flow/Flow;Ljava/lang/Object;Lkotlin/coroutines/CoroutineContext;Lb/b/e/q;II)Lb/b/e/cu; @92: invokestatic
  Reason:
    Type 'kotlin/jvm/functions/Function2' (current frame, stack[3]) is not assignable to 'b/b/e/ch'
  Current Frame:
    bci: @92
    flags: { }
    locals: { 'kotlinx/coroutines/flow/Flow', 'java/lang/Object', 'kotlin/coroutines/CoroutineContext', 'b/b/e/q', integer }
    stack: { 'java/lang/Object', 'kotlinx/coroutines/flow/Flow', 'kotlin/coroutines/CoroutineContext', 'kotlin/jvm/functions/Function2', 'b/b/e/q', integer }
  Bytecode:
    0000000: 2a12 07b8 0022 2d12 01b9 0023 0200 1505
    0000010: 057e 9900 0ab2 001a c000 154d b800 1b99
    0000020: 0019 1201 1504 0212 083a 0636 0536 0536
    0000030: 0519 0612 07b8 0022 2b2a 2cbb 000e 592c
    0000040: 2a01 b700 20c0 0017 2d11 1240 1008 1504
    0000050: 067a 7e80 100e 1504 067a 7e80 b800 1f4b
    0000060: 2db9 0024 0100 2ab0                    
  Stackmap Table:
    chop_frame(@28,1)
    same_frame(@56)

	at b.b.e.cb.a(Unknown Source)
	...

Proguard 7.2.2 works fine.

[sproctor]

Still existing in 7.5.0.

[mrjameshamilton]

Hi @sproctor ! Can you share a reproducing sample?

[sproctor]

Sorry, I don't have an example to share. It seems to be Compose related.

Error with 7.6.0:

Exception in thread "main" java.lang.VerifyError: Bad return type
Exception Details:
  Location:
    b/c/e/ch.a(Lkotlin/jvm/functions/Function0;)Lb/c/e/X; @18: areturn
  Reason:
    Type 'b/c/e/cA' (current frame, stack[0]) is not assignable to 'b/c/e/X' (from method signature)
  Current Frame:
    bci: @18
    flags: { }
    locals: { 'kotlin/jvm/functions/Function0' }
    stack: { 'b/c/e/cA' }
  Bytecode:
    0000000: 2a12 06b8 0016 bb00 0759 2a01 b700 11c0
    0000010: 000a b0                                

        at b.c.e.u.b(SourceFile:52298)
        at b.c.e.u.a(SourceFile:3522)
        at b.c.e.F.c(SourceFile:743)
        at b.c.e.bn.a(SourceFile:1122)
        at b.c.e.F.d(SourceFile:649)
        at b.c.e.F.a(SourceFile:635)
        at b.c.f.x.j.invokeSuspend(SourceFile:221)
        at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:33)
        at kotlinx.coroutines.DispatchedTask.run(SourceFile:101)
        at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:318)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:773)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:720)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:714)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
        at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
        at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

From the mappings:

androidx.compose.runtime.ComposerImpl -> b.c.e.u:
# {"fileName":"Composer.kt","id":"sourceFile"}
    androidx.compose.runtime.Applier applier -> b
    androidx.compose.runtime.CompositionContext parentContext -> c
...
androidx.compose.runtime.DerivedSnapshotState -> b.c.e.X:
# {"fileName":"DerivedState.kt","id":"sourceFile"}
...
androidx.compose.runtime.State -> b.c.e.cA:
# {"fileName":"SnapshotState.kt","id":"sourceFile"}
    java.lang.Object getValue() -> b

Adding the following fixes the issue:

-keep class androidx.compose.runtime.* { *; }

[mrjameshamilton]

Hi @sproctor ! It seems to be related to optimizations, if that's the case you could still allow shrinking and name obfuscation of the package with:

-keep,allowshrinking,allowobfuscation class androidx.compose.runtime.* { *; }

You could also disable specific optimizations, for example there is a known issue with enum simplication (#350):

-optimizations !class/unboxing/enum

If you can't share a full sample, it might help to share the bytecode for the specific class/method before and after, which you can dump with javap.