Abduqodiri Qurbonzoda
7346cf4777
Merge-request: KT-MR-6930 Merged-by: Abduqodiri Qurbonzoda <abduqodiri.qurbonzoda@jetbrains.com>
47 lines
2.3 KiB
Markdown
47 lines
2.3 KiB
Markdown
# Verifies that a library compiled with a newer JDK is compatible with older JDK API
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Currently, the project only checks `kotlin-reflect` for JDK 1.6 compatibility.
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The check is necessary to make sure applications using `kotlin-reflect` can run on older Android devices.
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## How to run
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Run from the root directory of the kotlin project:
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`./gradlew :tools:jdk-api-validator:test`
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## How to interpret the result
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Successful completion of the `test` task means the checked libraries are compatible with JDK 1.6 API.
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In case of failure, the exact location and name of the violating API references are logged as error.
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An example of validation error:
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`[ERROR] /kotlin/libraries/reflect/build/libs/kotlin-reflect-1.9.255-SNAPSHOT.jar:kotlin/reflect/jvm/internal/ComputableClassValue.class:47: Undefined reference: void ClassValue.<init>()`
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## How to fix a failure
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If the violating reference can be desugared by R8 or its execution is prevented on Android platform,
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the error can be suppressed. See `suppressAnnotations` and `undefinedReferencesToIgnore` in `JdkApiUsageTest.kt`.
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Otherwise, the API should be avoided.
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To check if an API can be desugared by R8:
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1. Identify the earliest R8 version that supports current Kotlin version [here](https://developer.android.com/build/kotlin-support).
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2. Download the R8 version jar artifact from Google's maven repository [here](https://maven.google.com/web/index.html#com.android.tools:r8).
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3. Run it using the `BackportedMethodList` entry point, e.g., `java -cp r8-8.0.40.jar com.android.tools.r8.BackportedMethodList`.
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4. Check if the violating API reference is in the printed list of methods.
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Also, you can get the list of backported methods the downloaded version supports for a given Android API level:
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```shell
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$ java -cp r8-8.0.40.jar com.android.tools.r8.BackportedMethodList --help
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Usage: BackportedMethodList [options]
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Options are:
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--output <file> # Output result in <file>.
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--min-api <number> # Minimum Android API level for the application
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--desugared-lib <file> # Desugared library configuration (JSON from the
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# configuration)
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--lib <file> # The compilation SDK library (android.jar)
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--version # Print the version of BackportedMethodList.
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--help # Print this message.
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```
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