Problem regarding Java SPI in R8 shrinker of versions 8.6.*, 8.7.*, 8.8.0 [389737060]

Fixed

Bug

Status Update

No update yet.

Description

zh...@gmail.com

created issue #1

Jan 14, 2025 10:31AM

Summary

There is a problem with the R8 shrinker in versions 8.6., 8.7., and 8.8.0, where it improperly strips code related to Java Service Provider Interface (SPI) usage. This issue occurs when a class is provided via the Java SPI API using ServiceLoader.load(SomeInterface.class) without direct references from other code. While the service provider class is retained, some of its code is stripped, leading to runtime errors.

Affected Versions

R8 versions: 8.6., 8.7., 8.8.0 (latest release at the time of reporting)

Description

The issue arises when using Java SPI to load service providers. Specifically, when a class is loaded using ServiceLoader.load(SomeInterface.class) and there are no direct references to it from other parts of the code, R8 retains the service provider class but strips some of its code. This results in a NullPointerException (NPE) during runtime.

Reproduction Steps

Set up a project with the following module structure:
```
.
├── app
├── api
└── provider
```

Implement the following code:

MainActivity.kt in the :app module:

import ...
import com.example.api.Spi

class MainActivity : Activity() {
    ...
    private fun testApi() {
        val api = Spi.instance.createApi() // Got null in the release build
        Log.d("MainActivity", "api: $api")
        api.querySomething() // Crashes here due to a NPE
    }
}

Api.kt in the :api module:

pacakge com.example.api
...
interface Spi {
    fun createApi(): Api
    companion object {
        @JvmStatic
        val instance: Spi by lazy {
            ServiceLoader.load(Spi::class.java).firstOrNull() ?: error("Missing Api provider")
        }
    }
}
interface Api {
    fun querySomething(): String
}

MyApi.kt in the :provider module:

pacakge com.example.provider
import com.example.api.Api
import com.example.api.Spi
class MySpi : Spi {
    @Volatile
    private var myApi: Api? = null

    /**
     * The dex byte code of this method is when obfuscated:
     * ```
     * .method public a()Lz/a;
     *     .registers 2
     *
     *     .line 1
     *     const/4 v0, 0x0
     *
     *     .line 2
     *     return-object v0
     * .end method
     * ```
     */
    override fun createApi(): Api {
        return myApi ?: synchronized(this) {
            myApi ?: MyApi().also { myApi = it }
        }
    }
}
class MyApi : Api {
    override fun querySomething(): String {
        return "Hello from MyApi"
    }
}

add the service provider file (named com.example.api.Spi) in src/main/resources/META-INF/service/ in the provider:
```
com.example.provider.MySpi
```

Configure the build.gradle.kts in the :app module as follows:

dependencies {
    api(project(":api"))
    runtimeOnly(project(":provider"))
}

Build the project in release mode with R8 enabled.
Run the application and observe the NullPointerException when testApi() is called.

Expected Behavior

The service provider class and its methods should be fully retained by R8, allowing the application to run without errors.

Actual Behavior

The service provider class is retained, but some of its code is stripped, leading to a NullPointerException during runtime.

Additional Information

The full source code for reproducing this issue can be found at: https://github.com/zhcnxf/testagp87

Comments

ch...@google.com <ch...@google.com> Jan 14, 2025 10:34AM

Reassigned to cl...@google.com.

cl...@google.com <cl...@google.com> #2Feb 6, 2025 12:56PM

Reassigned to ch...@google.com.

Could you look into it @christofferqa?

The issue is with this class:

class MySpi : Spi {
    @Volatile
    private var myApi: Api? = null

    // Incorrectly rewritten to return null;
    override fun createApi(): Api {
        return myApi ?: synchronized(this) {
            myApi ?: MyApi().also { myApi = it }
        }
    }
}

The error seems to be that the ArgumentPropagator believes that the fieldState of myApi is ExactDynamicType(@NotNull MyApi) while it should be ExactDynamicType(@Nullable MyApi)

It then removes the first branch (assuming myApi is not null):

return myApi ?: synchronized(this) {
            myApi ?: MyApi().also { myApi = it }
        }

is rewritten into:

return myApi

And then it eventually concludes that myApi is always null, replacing the code by

return null

The ArgumentPropagatorCodeScanner analyzes the assignment myApi = it and correctly set join the state to ExactDynamicType(@NotNull MyApi)

However the ArgumentPropagator fails to understand that myApi can be read before being written in the method, relying on the default null value, so it fails to join null to the dynamic type.

ch...@google.com <ch...@google.com> #3Feb 7, 2025 11:09AM

Reassigned to cl...@google.com.

Yes I can take a look. Would it be possible for you to add a regression test of this issue?

ch...@google.com <ch...@google.com> Feb 12, 2025 07:53AM

Reassigned to ch...@google.com.

ap...@google.com <ap...@google.com> #4Feb 13, 2025 09:35AM

Project: r8
Branch: main
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101407

Reproduce field propagation issue with ServiceLoader

Expand for full commit details

Reproduce field propagation issue with ServiceLoader 
 
Bug: b/389737060 
Change-Id: Id850448f68b999194bc0380dfca625f4f68bc31b

Files:

A src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 6ba9af34b15f2a0d3fe356f6e7a5a4071128aed9
Date: Wed Feb 12 09:31:01 2025

ap...@google.com <ap...@google.com> #5Feb 13, 2025 09:35AM

Marked as fixed.

Project: r8
Branch: main
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101408

Account for ServiceLoaders in field value propagation

Expand for full commit details

Account for ServiceLoaders in field value propagation 
 
Fixes: b/389737060 
Change-Id: Ide438a8e1b0541f3ce2385087f06f8b9909ab3c5

Files:

M src/main/java/com/android/tools/r8/optimize/argumentpropagation/propagation/DefaultFieldValueJoiner.java
M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 692fff07b70f6ee5ac520b179aed5e125a0d4848
Date: Wed Feb 12 09:34:04 2025

ap...@google.com <ap...@google.com> #6Feb 13, 2025 09:55AM

Project: r8
Branch: 8.9
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101512

Account for ServiceLoaders in field value propagation

Expand for full commit details

Account for ServiceLoaders in field value propagation 
 
Fixes: b/389737060 
Change-Id: Ide438a8e1b0541f3ce2385087f06f8b9909ab3c5

Files:

M src/main/java/com/android/tools/r8/optimize/argumentpropagation/propagation/DefaultFieldValueJoiner.java
M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 76cad195cf43c16aa9e7b0203e51662036587e71
Date: Thu Feb 13 10:33:29 2025

ap...@google.com <ap...@google.com> #7Feb 13, 2025 09:55AM

Project: r8
Branch: 8.9
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101522

Version 8.9.28

Expand for full commit details

Version 8.9.28 
 
Bug: b/389737060 
Change-Id: I42c8d3194dc053e3a16eef8ea1c4b3aced6752d6

Files:

M src/main/java/com/android/tools/r8/Version.java

Hash: 668c1778e857c1bc8e3f9308a65ddc01a6c14898
Date: Thu Feb 13 10:33:34 2025

ap...@google.com <ap...@google.com> #8Feb 13, 2025 09:55AM

Project: r8
Branch: 8.9
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101511

Reproduce field propagation issue with ServiceLoader

Expand for full commit details

Reproduce field propagation issue with ServiceLoader 
 
Bug: b/389737060 
Change-Id: Id850448f68b999194bc0380dfca625f4f68bc31b

Files:

A src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: a76d3e8637b5280dcc972ed9fabc74bb503cc30c
Date: Thu Feb 13 10:33:24 2025

ap...@google.com <ap...@google.com> #9Feb 13, 2025 09:55AM

Project: r8
Branch: 8.8
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101513

Reproduce field propagation issue with ServiceLoader

Expand for full commit details

Reproduce field propagation issue with ServiceLoader 
 
Bug: b/389737060 
Change-Id: Id850448f68b999194bc0380dfca625f4f68bc31b

Files:

A src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: a63678f7ebb3321af74c9846be9c851e4da78e4f
Date: Thu Feb 13 10:33:55 2025

ap...@google.com <ap...@google.com> #10Feb 13, 2025 09:55AM

Project: r8
Branch: 8.8
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101514

Version 8.8.35

Expand for full commit details

Version 8.8.35 
 
Bug: b/389737060 
Change-Id: I2361f77b42b529f2cbdfbf60fbe4a95e405ba716

Files:

M src/main/java/com/android/tools/r8/Version.java

Hash: d280891c805561bc120f5f96841b50353e74edfe
Date: Thu Feb 13 10:34:06 2025

ap...@google.com <ap...@google.com> #11Feb 13, 2025 09:55AM

Project: r8
Branch: 8.8
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101523

Account for ServiceLoaders in field value propagation

Expand for full commit details

Account for ServiceLoaders in field value propagation 
 
Fixes: b/389737060 
Change-Id: Ide438a8e1b0541f3ce2385087f06f8b9909ab3c5

Files:

M src/main/java/com/android/tools/r8/optimize/argumentpropagation/propagation/DefaultFieldValueJoiner.java
M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 05dd13d906b60efdf03caea7067dedf67b7c6a2e
Date: Thu Feb 13 10:34:00 2025

ap...@google.com <ap...@google.com> #12Feb 13, 2025 09:55AM

Project: r8
Branch: 8.7
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101540

Account for ServiceLoaders in field value propagation

Expand for full commit details

Account for ServiceLoaders in field value propagation 
 
Fixes: b/389737060 
Change-Id: Ide438a8e1b0541f3ce2385087f06f8b9909ab3c5

Files:

M src/main/java/com/android/tools/r8/optimize/argumentpropagation/propagation/DefaultFieldValueJoiner.java
M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: d7dcc9001453052f772056337d3c120dba34fc46
Date: Thu Feb 13 10:34:31 2025

ap...@google.com <ap...@google.com> #13Feb 13, 2025 09:55AM

Project: r8
Branch: 8.7
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101541

Version 8.7.35

Expand for full commit details

Version 8.7.35 
 
Bug: b/389737060 
Change-Id: Icfb60f565b329600b5f167a496a39a61ebff9ea6

Files:

M src/main/java/com/android/tools/r8/Version.java

Hash: 1be71bdf4455bbc565502b4c3bbbae64608c57a6
Date: Thu Feb 13 10:34:38 2025

ap...@google.com <ap...@google.com> #14Feb 13, 2025 09:56AM

Project: r8
Branch: 8.7
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101515

Reproduce field propagation issue with ServiceLoader

Expand for full commit details

Reproduce field propagation issue with ServiceLoader 
 
Bug: b/389737060 
Change-Id: Id850448f68b999194bc0380dfca625f4f68bc31b

Files:

A src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 7272540b4f7850ef22543defc221660359704ea2
Date: Thu Feb 13 10:34:26 2025

ap...@google.com <ap...@google.com> #15Feb 13, 2025 09:59AM

Project: r8
Branch: 8.9
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101512

Account for ServiceLoaders in field value propagation

Expand for full commit details

Account for ServiceLoaders in field value propagation 
 
Fixes: b/389737060 
Change-Id: Ide438a8e1b0541f3ce2385087f06f8b9909ab3c5

Files:

M src/main/java/com/android/tools/r8/optimize/argumentpropagation/propagation/DefaultFieldValueJoiner.java
M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 76cad195cf43c16aa9e7b0203e51662036587e71
Date: Thu Feb 13 10:33:29 2025

ap...@google.com <ap...@google.com> #16Feb 13, 2025 09:59AM

Project: r8
Branch: 8.9
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101511

Reproduce field propagation issue with ServiceLoader

Expand for full commit details

Reproduce field propagation issue with ServiceLoader 
 
Bug: b/389737060 
Change-Id: Id850448f68b999194bc0380dfca625f4f68bc31b

Files:

A src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: a76d3e8637b5280dcc972ed9fabc74bb503cc30c
Date: Thu Feb 13 10:33:24 2025

ch...@google.com <ch...@google.com> #17Feb 13, 2025 10:55AM

This should now be fixed in R8 8.7.36, 8.8.36 and 8.9.28.

Message last modified on Feb 13, 2025 11:32AM

ap...@google.com <ap...@google.com> #18Feb 13, 2025 12:00PM

Project: r8
Branch: 8.8
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101518

Version 8.8.36

Expand for full commit details

Version 8.8.36 
 
Bug: b/389737060 
Change-Id: I9ac9a6eda36030b2569bf6839f9b55257f0d2888

Files:

M src/main/java/com/android/tools/r8/Version.java

Hash: d228eeda266e288da18698a2fa464fc97b0303c3
Date: Thu Feb 13 12:31:37 2025

ap...@google.com <ap...@google.com> #19Feb 13, 2025 12:00PM

Project: r8
Branch: 8.8
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101547

Fix call to addDataResources in test

Expand for full commit details

Fix call to addDataResources in test 
 
This was added in 8.9. 
 
Bug: b/389737060 
Change-Id: I604550f0c0034256f71c03874eeb4798f7079f18

Files:

M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 58502e8fa34f0abe33a254671faf1b74e0668c86
Date: Thu Feb 13 12:30:57 2025

ap...@google.com <ap...@google.com> #20Feb 13, 2025 12:00PM

Project: r8
Branch: 8.7
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101546

Version 8.7.36

Expand for full commit details

Version 8.7.36 
 
Bug: b/389737060 
Change-Id: Ib57157e3ca8863dcb097a3aa0a1e840c546a4392

Files:

M src/main/java/com/android/tools/r8/Version.java

Hash: de384a5950a14b2244dc74819fffd0306cae7065
Date: Thu Feb 13 12:28:52 2025

ap...@google.com <ap...@google.com> #21Feb 13, 2025 12:00PM

Project: r8
Branch: 8.7
Author: Christoffer Adamsen <christofferqa@google.com>
Link: https://r8-review.googlesource.com/101545

Fix call to addDataResources in test

Expand for full commit details

Fix call to addDataResources in test 
 
This was added in 8.9. 
 
Bug: b/389737060 
Change-Id: I04d342dc297474d141362290f9ccf22c48332446

Files:

M src/test/java/com/android/tools/r8/ir/optimize/membervaluepropagation/DefaultFieldValueJoinerWithServiceLoaderTest.java

Hash: 981af34dd96a316d0c11972d80ce31ab301ec6c1
Date: Thu Feb 13 12:28:09 2025

an...@google.com <an...@google.com> #22Mar 18, 2025 07:54PM

Thank you for your patience while our engineering team worked to resolve this issue. A fix for this issue is now available in:

Android Studio Meerkat Feature Drop | 2024.3.2 Beta 1
Android Gradle Plugin 8.10.0-beta01

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

Thank you for taking the time to submit feedback — we really appreciate it!

an...@google.com <an...@google.com> #23Mar 24, 2025 05:40PM

The fixes for this issue are now also available in:

Android Studio Meerkat | 2024.3.1 Patch 1
Android Gradle Plugin 8.9.1

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

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