Espresso 3.5.0-alpha06 crashes with IncompatibleClassChangeError on API 30 & below

[gmk57]

Description

After upgrading to Espresso 3.5.0-alpha06 any view assertion (onView(...).check(matches(...))) crashes on API 30 & below.

The same tests work with Espresso 3.4.0 & 3.5.0-alpha05, so it seems to be a regression.

Steps to Reproduce

1. Create new project, with a basic Espresso test
2. Upgrade Espresso to 3.5.0-alpha06
3. Run test on device or emulator with API 21-30

Expected Results

Test should pass

Actual Results

Test fails with

java.lang.IncompatibleClassChangeError: Class 'org.hamcrest.StringDescription' does not implement interface 'java.lang.Iterable' in call to 'java.util.Iterator java.lang.Iterable.iterator()' (declaration of 'org.hamcrest.BaseDescription' appears in /data/app/~~0euuGogwUQ-CS9qM-ORXEg==/gmk57.testespresso.test-kBqLXiNXd4caXIOy6UsVNA==/base.apk)
at org.hamcrest.BaseDescription.appendValueList(BaseDescription.java:76)
at androidx.test.espresso.matcher.BoundedDiagnosingMatcher.describeTo(BoundedDiagnosingMatcher.java:4)
at org.hamcrest.BaseDescription.appendDescriptionOf(BaseDescription.java:24)
at org.hamcrest.StringDescription.toString(StringDescription.java:28)
at org.hamcrest.BaseMatcher.toString(BaseMatcher.java:28)
at java.util.Formatter$FormatSpecifier.printString(Formatter.java:2978)
at java.util.Formatter$FormatSpecifier.print(Formatter.java:2855)
at java.util.Formatter.format(Formatter.java:2524)
at java.util.Formatter.format(Formatter.java:2459)
at java.lang.String.format(String.java:2911)
at androidx.test.espresso.ViewInteraction$2.call(ViewInteraction.java:12)
at androidx.test.espresso.ViewInteraction$2.call(ViewInteraction.java:1)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

On API 21-25 the error is phrased differently:

java.lang.IncompatibleClassChangeError: The method 'java.lang.Class java.lang.Object.getClass()' was expected to be of type interface but instead was found to be of type virtual (declaration of 'androidx.test.platform.tracing.Tracing' appears in /data/app/gmk57.testespresso.test-1/base.apk)

AndroidX Test and Android OS Versions

Android API 21-30 (not reproducible on 31, not tested on 32)
androidx.test.ext:junit:1.1.3
androidx.test.espresso:espresso-core:3.5.0-alpha06
Android Studio Bumblebee | 2021.1.1 Patch 3

Link to a public git repo demonstrating the problem:

Should be easily reproduced from scratch, but here it is

[brettchabot]

Thanks for reporting this.

The problem is also not reproducible on AGP 7.3.0-alpha07 (which is why our release tests did not catch this). I'm wondering if this is related to this fix made in D8: https://issuetracker.google.com/218298666

[TWiStErRob]

Based on the report in OP, it's occurs only after a specific version, what could've changed between those versions? r8, which builds Espresso?

[brettchabot]

Nothing changed in BoundedDiagnosingMatcher, so yes my theory is some sort of toolchain change.

The version of R8/D8 did change from 3.3.14-dev to 3.3.28-dev for alpha05->alpha06

[brettchabot]

I suspect its a javac upgrade that causes this issue.

This is the line that triggers the issue in BoundedDiagnosingMatcher#describeTo

String implDescriptionString =  implDescription.toString();

In 3.5.0-alpha05 this is compiled to the following bytecode:

24: invokevirtual #105                // Method java/lang/Object.toString:()Ljava/lang/String;

In 3.5.0-alpha06 this becomes:

24: invokeinterface #103,  1          // InterfaceMethod org/hamcrest/Description.toString:()Ljava/lang/String;

I don't understand this part of it well but from reading https://issuetracker.google.com/218298666 it sounds like older versions of D8 would generate dex not handled by older ART versions.

I tried to find a general workaround that could be applied to the androidx.test release toolchain but haven't found anything yet.

I was able to find a simple workaround for this particular case, but its concerning because it seems like this issue could crop up anywhere. And it is also reproducible in AGP 7.2.0.

[brettchabot]

This was indeed not a complete fix

[brettchabot]

The androidx.test release toolchain was reverted to use the previous javac version. Please use espresso 3.5.0-alpha07

[elevenfive]

@brettchabot I'm still seeing the IncompatibleClassChangeError on Android 8.0 with Espresso versions 3.5.0 & 3.5.1 and Android Gradle Plugin 7.1.3.

[brettchabot]

ack tracking here #1642 as the symptoms seem slightly different