IssueTracker

Thank you for posting an issue and providing a reproduction. This is a bug in R8 where we remove Monitor-Enter and Monitor-Exit instructions where we are not allowed to. I will create a local test and fix for it shortly. A temporary fix to the issue is to add the following keep rule:

-keep class okio.SegmentPool { *; }

Adding the above fixes the issue for me in the reproduction, however, since we are removing monitor instructions in an unsound way, I cannot promise the above will be sufficient for your project. Can I ask you to try it out and report back while I work on a fix?

Thanks, that keep rule seems to resolve the issue on both the repro project & my real project!

Project: r8
Branch: master

commit 99125526c11ad4d8c686d3f8e4a2366aa1e3e12c
Author: Morten Krogh-Jespersen <mkroghj@google.com>
Date:   Tue Jan 14 08:56:19 2020

    Do not classinline when root is a static get and is used with a monitor
   
    We can only remove monitor instructions in the class inliner, when the
    root is a new instance. For static get roots, we cannot guarantee that
    the instance is not shared.
   
    Bug: 147411673
    Change-Id: I4d5463ceecbde2941c3431510295551bfc2d9766

M       src/main/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerEligibilityInfo.java
M       src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
M       src/main/java/com/android/tools/r8/ir/optimize/info/MethodOptimizationInfoCollector.java
M       src/main/java/com/android/tools/r8/ir/optimize/info/ParameterUsagesInfo.java
A       src/test/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerStaticGetDirectMonitorTest.java
A       src/test/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerStaticGetExtraMethodMonitorTest.java
A       src/test/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerStaticGetMonitorTest.java

https://r8-review.googlesource.com/47280

Project: r8
Branch: 2.0

commit 3df603d82316846021d557954be5e1f5b3c98aa3
Author: Morten Krogh-Jespersen <mkroghj@google.com>
Date:   Wed Jan 15 16:12:54 2020

    Version 2.0.15
   
    Cherry-pick: Fix version test when we are on a release branch
    CL: https://r8-review.googlesource.com/47564
   
    Cherry-pick: Reland "Do not rewrite generic signatures in target of
    merged classes"
    CL: https://r8-review.googlesource.com/47512
   
    Cherry-pick: Do not classinline when root is a static get and is used with a monitor
    CL: https://r8-review.googlesource.com/47280
   
    Cherry-pick: Allow for '.' for patterns when parsing -keepattributes
    CL: https://r8-review.googlesource.com/47321
   
    Cherry-pick: Fix proguard configuration parser test to allow classname in attribute
    CL: https://r8-review.googlesource.com/47361
   
    Bug: 147386014
    Bug: 147411673
    Bug: 147470785
    Change-Id: If56d14012b6121ab76416ea7d8a8dda78d02136e

M       src/main/java/com/android/tools/r8/Version.java
M       src/main/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerEligibilityInfo.java
M       src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
M       src/main/java/com/android/tools/r8/ir/optimize/info/MethodOptimizationInfoCollector.java
M       src/main/java/com/android/tools/r8/ir/optimize/info/ParameterUsagesInfo.java
M       src/main/java/com/android/tools/r8/naming/ClassNameMinifier.java
M       src/main/java/com/android/tools/r8/naming/signature/GenericSignatureAction.java
M       src/main/java/com/android/tools/r8/naming/signature/GenericSignatureParser.java
M       src/main/java/com/android/tools/r8/naming/signature/GenericSignatureRewriter.java
M       src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
M       src/main/java/com/android/tools/r8/shaking/VerticalClassMerger.java
M       src/main/java/com/android/tools/r8/utils/IteratorUtils.java
M       src/test/java/com/android/tools/r8/VersionTests.java
A       src/test/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerStaticGetDirectMonitorTest.java
A       src/test/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerStaticGetExtraMethodMonitorTest.java
A       src/test/java/com/android/tools/r8/ir/optimize/classinliner/ClassInlinerStaticGetMonitorTest.java
M       src/test/java/com/android/tools/r8/naming/GenericSignatureParserTest.java
A       src/test/java/com/android/tools/r8/naming/signature/SignatureOfMergedClassesTest.java
A       src/test/java/com/android/tools/r8/naming/signature/merging/I.java
A       src/test/java/com/android/tools/r8/naming/signature/merging/ImplI.java
A       src/test/java/com/android/tools/r8/naming/signature/merging/ImplK.java
A       src/test/java/com/android/tools/r8/naming/signature/merging/InterfaceToKeep.java
A       src/test/java/com/android/tools/r8/naming/signature/merging/J.java
A       src/test/java/com/android/tools/r8/naming/signature/merging/K.java
M       src/test/java/com/android/tools/r8/shaking/ProguardConfigurationParserTest.java
A       src/test/java/com/android/tools/r8/shaking/attributes/KeepAttributesDotsTest.java
M       src/test/java/com/android/tools/r8/utils/codeinspector/CodeInspector.java

https://r8-review.googlesource.com/47610