How to change the proguard mapping file name in gradle for Android project

As of today (May 2020) former solution, which uses variant.mappingFile is not working anymore in new Android Gradle plugin (Android Studio) 3.6 and higher.

Instead variant.mappingFile returns null and following is displayed in the logs:

WARNING: API 'variant.getMappingFile()' is obsolete and has been replaced with 'variant.getMappingFileProvider()'.

I am sharing my working solution, which uses new api:

    applicationVariants.all { variant ->
        variant.assembleProvider.get().doLast {
            def mappingFiles = variant.getMappingFileProvider().get().files

            for (file in mappingFiles) {
                if (file != null && file.exists()) {
                    def nameMatchingApkFile = "$archivesBaseName-$variant.baseName-$file.name"
                    def newMappingFile = new File(file.parent, nameMatchingApkFile)

                    newMappingFile.delete() //clean-up if exists already
                    file.renameTo(newMappingFile)
                }
            }
        }
    }

Note, that variant.getBuildType().isMinifyEnabled() is not used since we are using DexGuard.

The code above makes mapping file's name match apk's file name.

Just in case, if you need to change apk name - following could be used:

android {
    defaultConfig {
        //resulting apk will looks like: "archive base name" + -<flavour>-<buildType>.apk
        archivesBaseName = "$applicationId-$versionName"
    }
}

Simpler solution.

applicationVariants.all { variant ->
        if (variant.getBuildType().isMinifyEnabled()) {
            variant.assemble.doLast {
                copy {
                    from variant.mappingFile
                    into "${rootDir}/proguardTools"
                    rename { String fileName ->
                        "mapping-${variant.name}.txt"
                    }
                }
            }
        }
    }