Android: exclude the main apk deps from the test apk (#6073)

This is related to #6064

### Improvements

- Aligning base module and androidTest dependencies is [no longer
necessary](https://github.com/vaslabs-ltd/compose-samples-with-mill/pull/6/files#diff-35fe6f53838971f482104d05f316647dead2c9fff13e5df4f7f2c7ad200e6a0dL95)
- Properly passing compile classpath to R8 makes the R8 workaround error
-> warning mapping [not
necessary](https://github.com/vaslabs-ltd/compose-samples-with-mill/pull/6/files#diff-35fe6f53838971f482104d05f316647dead2c9fff13e5df4f7f2c7ad200e6a0dL85)
- The test apk size is now greatly reduced (from >20MB to <1MB in most
cases)
- With the new AndroidR8InstrumentedTestsModule , androidTests apk can
also be minified as the `androidGeneratedMinifyKeepRules` is only
available in R8 modules


| App | Mill Size | Gradle Size |
|------ |  ----------- | ------------------|
| Jetchat | 760KB | 1019KB | 
| JetNews|742KB|999KB|
| Architecture Samples | 4.3MB | 5.6MB |

### Fixes

- Cyclic dependency issue when compiling r classes
- Jetchat android tests

### Implementation details 

Introduced a new `AndroidR8InstrumentedTestsModule` which builds the
test apk excluding the dependency tree of the base module (base apk)
with 2 important tasks:

- `androidR8CompileOnlyClasspath` incorporates the whole base apk (but
as a jar file)
- `androidResolvedPackagableMvnDeps` excludes the dependencies of the
base module via `androidPackagableMvnDeps` and is used in place of
`resolvedRunMvnDeps` .

### Extensions

To do the dependency resolution again by excluding the dependency tree,
without breaking the examples, I needed a way to pass the bom to the
`defaultResolver().classpath` . Thus I extended the methods needed and
fixed any MiMa issues with `@unroll` , although I haven't used it
before, this is what I've found from looking around, so please let me
know if this was a mistake

### Further work

Testing a few apps, there was a case where a test dependency was pulling
`com.google.android.material:material` which in turn depends on
appcompat android resources, so aapt2 linking was failing.

I tried to see if `aapt2 link` `-I` argument would be of any help, but
it seems I'm missing something, it appears only one artifact can be
passed to it, tried several usage variations without luck

Gradle incorporates these resources without an issue, so it means we
need to find a way to link the resources against the base module
resources and at the same time avoid duplicate contents

I think it's a very niche use case, as typically runtime usage of these
resources will be done in the base apk. For now, I added the appcompat
explicitly in the androitTest mvnDeps so the linking goes through

Author: vaslabs

example/thirdparty/android-compose-samples/build.mill

@@ -273,7 +273,6 @@ object Jetchat extends mill.api.Module {
       mvn"org.jetbrains.kotlinx:kotlinx-coroutines-android:1.10.2",
       mvn"androidx.activity:activity-compose:1.10.1",
       mvn"androidx.core:core-ktx:1.16.0",
-      mvn"androidx.appcompat:appcompat:1.7.0",
       mvn"androidx.compose.runtime:runtime-livedata",
       mvn"androidx.lifecycle:lifecycle-viewmodel-compose:2.9.0",
       mvn"androidx.lifecycle:lifecycle-runtime-compose:2.9.0",
@@ -288,8 +287,7 @@ object Jetchat extends mill.api.Module {
       mvn"androidx.databinding:viewbinding:8.13.0",
       mvn"androidx.compose.ui:ui-tooling",
       mvn"androidx.compose.ui:ui-tooling-preview",
-      mvn"androidx.compose.ui:ui-test-manifest",
-      mvn"com.google.android.material:material:1.6.0"
+      mvn"androidx.compose.ui:ui-test-manifest"
     )
 
     def androidSdkModule = mill.api.ModuleRef(androidSdkModule0)
@@ -298,12 +296,6 @@ object Jetchat extends mill.api.Module {
 
     def androidMinSdk = Versions.androidMinSdk
 
-    /*
-     * FIXME Currently broken with
-     * Message 2) profileScreen_back_conversationScreen(com.example.compose.jetchat.NavigationTest)
-     * android.content.res.Resources$NotFoundException: String resource ID #0x7f0c002b
-     * Message android.content.res.Resources$NotFoundException: String resource ID #0x7f0c002b
-     */
     object androidTest extends AndroidAppKotlinInstrumentedTests, AndroidR8AppModule {
       override def bomMvnDeps = super.mvnDeps() ++ Seq(
         mvn"androidx.compose:compose-bom:2025.08.00"
@@ -317,9 +309,6 @@ object Jetchat extends mill.api.Module {
         true
       }
 
-      // FIXME: R8 should compile without missing classes errors
-      override def androidR8Args = Seq("--map-diagnostics", "error", "warning")
-
       def mvnDeps = super.mvnDeps() ++ Seq(
         mvn"junit:junit:4.13.2",
         mvn"androidx.test:core:1.6.1",
@@ -330,10 +319,8 @@ object Jetchat extends mill.api.Module {
         mvn"org.jetbrains.kotlinx:kotlinx-coroutines-test:1.10.2",
         mvn"androidx.compose.ui:ui-test",
         mvn"androidx.compose.ui:ui-test-junit4",
-        mvn"androidx.collection:collection-ktx:1.5.0",
-        mvn"androidx.savedstate:savedstate-ktx:1.3.0",
-        mvn"androidx.appcompat:appcompat:1.7.0",
-        mvn"androidx.lifecycle:lifecycle-viewmodel-compose:2.9.0"
+        // FIXME temporary workaround to avoid linking error
+        mvn"androidx.appcompat:appcompat:1.7.0"
       )
 
     }

example/thirdparty/androidtodo/build.mill

@@ -67,7 +67,6 @@ object app
 
   def mvnDeps: T[Seq[Dep]] = super.mvnDeps() ++ Seq(
     mvn"androidx.core:core-ktx:1.15.0",
-    mvn"androidx.appcompat:appcompat:1.7.0",
     mvn"androidx.annotation:annotation:1.9.1",
     mvn"org.jetbrains.kotlinx:kotlinx-coroutines-android:1.9.0",
     mvn"com.jakewharton.timber:timber:5.0.1",
@@ -145,7 +144,7 @@ object app
 
   object androidTest
       extends AndroidAppKotlinInstrumentedTests,
-        AndroidR8AppModule,
+        AndroidR8InstrumentedTestsModule,
         AndroidHiltSupport {
 
     def moduleDeps = super.moduleDeps ++ Seq(`shared-test`)
@@ -164,7 +163,6 @@ object app
     }
 
     override def androidProjectProguardFiles = Task.Sources(
-      "proguard-rules.pro",
       "proguardTest-rules.pro"
     )
     override def androidDefaultProguardFileNames: Task[Seq[String]] = Task.Anon {
@@ -184,6 +182,7 @@ object app
       // Dependencies for Android unit tests
       mvn"junit:junit:4.13.2",
       mvn"org.jetbrains.kotlinx:kotlinx-coroutines-test:1.9.0",
+      mvn"androidx.appcompat:appcompat:1.7.0",
       // AndroidX Test - Instrumented testing
       mvn"androidx.test:core-ktx:1.6.1",
       mvn"androidx.test.ext:junit-ktx:1.2.1",

libs/androidlib/src/mill/androidlib/AndroidAppModule.scala

@@ -12,13 +12,14 @@ import mill.javalib.*
 import os.{Path, RelPath, zip}
 import os.RelPath.stringRelPathValidated
 import upickle.*
-import scala.concurrent.duration.*
 
+import scala.concurrent.duration.*
 import scala.jdk.OptionConverters.RichOptional
 import scala.xml.*
 import mill.api.daemon.internal.bsp.BspBuildTarget
 import mill.api.daemon.internal.EvaluatorApi
 import mill.javalib.testrunner.TestResult
+
 import scala.util.Properties.isWin
 
 /**
@@ -134,12 +135,13 @@ trait AndroidAppModule extends AndroidModule { outer =>
   )
 
   /**
-   * Collect files from META-INF folder of classes.jar (not META-INF of aar in case of Android library).
+   * Collect files from META-INF folder of [[androidPackagedDeps]] (not META-INF of aar in case of Android library).
+   * to include in the apk
    */
   def androidLibsClassesJarMetaInf: T[Seq[PathRef]] = Task {
     // ^ not the best name for the method, but this is to distinguish between META-INF of aar and META-INF
     // of classes.jar included in aar
-    compileClasspath()
+    androidPackagedDeps()
       .filter(ref =>
         ref.path.ext == "jar" &&
           ref != androidSdkModule().androidJarPath()
@@ -178,7 +180,6 @@ trait AndroidAppModule extends AndroidModule { outer =>
         }
       })
       .map(PathRef(_))
-      .toSeq
   }
 
   /**
@@ -189,7 +190,7 @@ trait AndroidAppModule extends AndroidModule { outer =>
   def androidPackageableExtraFiles: T[Seq[AndroidPackageableExtraFile]] =
     Task { Seq.empty[AndroidPackageableExtraFile] }
 
-  def androidPackageMetaInfoFiles: T[Seq[AndroidPackageableExtraFile]] = Task {
+  def androidPackagedMetaInfFiles: T[Seq[AndroidPackageableExtraFile]] = Task {
     def metaInfRoot(p: os.Path): os.Path = {
       var current = p
       while (!current.endsWith(os.rel / "META-INF")) {
@@ -239,7 +240,7 @@ trait AndroidAppModule extends AndroidModule { outer =>
         (androidPackageableExtraFile.source.path, androidPackageableExtraFile.destination.asSubPath)
       )
 
-    val metaInf = androidPackageMetaInfoFiles().map(asZipSource)
+    val metaInf = androidPackagedMetaInfFiles().map(asZipSource)
 
     val nativeDeps = androidPackageableNativeDeps().map(asZipSource)
 
@@ -894,9 +895,6 @@ trait AndroidAppModule extends AndroidModule { outer =>
 
     override def androidIsDebug: T[Boolean] = Task { true }
 
-    override def moduleDeps: Seq[JavaModule] = Seq.empty
-    override def compileModuleDeps: Seq[JavaModule] = Seq(outer)
-
     override def resolutionParams: Task[ResolutionParams] = Task.Anon(outer.resolutionParams())
 
     override def androidApplicationId: String = s"${outer.androidApplicationId}.test"
@@ -962,7 +960,7 @@ trait AndroidAppModule extends AndroidModule { outer =>
     }
 
     private def androidxTestManifests: Task[Seq[PathRef]] = Task {
-      androidUnpackArchives().flatMap {
+      androidUnpackRunArchives().flatMap {
         unpackedArchive =>
           unpackedArchive.manifest.map(_.path)
       }.filter {
@@ -1040,8 +1038,8 @@ trait AndroidAppModule extends AndroidModule { outer =>
       val device = androidTestInstall().apply()
 
       val instrumentOutput = os.proc(
-        (
-          androidSdkModule().adbExe().path,
+        Seq(
+          androidSdkModule().adbExe().path.toString,
           "-s",
           device,
           "shell",
@@ -1084,10 +1082,6 @@ trait AndroidAppModule extends AndroidModule { outer =>
         .map(PathRef(_))
     }
 
-    override def androidPackagedDeps: T[Seq[PathRef]] = Task {
-      androidResolvedRunMvnDeps()
-    }
-
     /**
      * The instrumented tests are packaged with testClasspath which already contains the
      * user compiled classes

libs/androidlib/src/mill/androidlib/AndroidModule.scala

@@ -525,7 +525,7 @@ trait AndroidModule extends JavaModule { outer =>
           sources = androidLibsRClasses().map(_.path),
           compileClasspath = Seq.empty,
           javacOptions = jOpts.compiler,
-          incrementalCompilation = zincIncrementalCompilation()
+          incrementalCompilation = true
         ),
         javaHome = javaHome().map(_.path),
         javaRuntimeOptions = jOpts.runtime,