src/test/java/com/android/tools/r8/classmerging/horizontal/interfaces/CollisionWithDefaultMethodOutsideMergeGroupAfterSubclassMergingTest.java

// Copyright (c) 2021, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

package com.android.tools.r8.classmerging.horizontal.interfaces;

import static com.android.tools.r8.utils.codeinspector.Matchers.isImplementing;
import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.assertFalse;

import com.android.tools.r8.NeverClassInline;
import com.android.tools.r8.NeverInline;
import com.android.tools.r8.NoHorizontalClassMerging;
import com.android.tools.r8.NoUnusedInterfaceRemoval;
import com.android.tools.r8.NoVerticalClassMerging;
import com.android.tools.r8.TestBase;
import com.android.tools.r8.TestParameters;
import com.android.tools.r8.TestParametersCollection;
import com.android.tools.r8.utils.codeinspector.ClassSubject;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

@RunWith(Parameterized.class)
public class CollisionWithDefaultMethodOutsideMergeGroupAfterSubclassMergingTest extends TestBase {

  private final TestParameters parameters;

  @Parameterized.Parameters(name = "{0}")
  public static TestParametersCollection data() {
    return getTestParameters().withAllRuntimesAndApiLevels().build();
  }

  public CollisionWithDefaultMethodOutsideMergeGroupAfterSubclassMergingTest(
      TestParameters parameters) {
    this.parameters = parameters;
  }

  // TODO(b/173990042): Disallow merging of A and B in the first round of class merging.
  @Test
  public void test() throws Exception {
    testForR8(parameters.getBackend())
        .addInnerClasses(getClass())
        .addKeepMainRule(Main.class)
        // I and J are not eligible for merging, since the merging of class B into class A
        // contributes the default method K.m() to A, and the merging of J into I would contribute
        // the default method J.m() to A.
        .addHorizontallyMergedClassesInspector(
            inspector -> {
              if (parameters.canUseDefaultAndStaticInterfaceMethods()) {
                inspector
                    .assertIsCompleteMergeGroup(A.class, B.class)
                    .assertMergedInto(B.class, A.class)
                    .assertClassesNotMerged(I.class, J.class, K.class);
              } else {
                inspector
                    .assertIsCompleteMergeGroup(A.class, B.class)
                    .assertMergedInto(B.class, A.class)
                    .assertIsCompleteMergeGroup(I.class, J.class)
                    .assertClassesNotMerged(K.class);
              }
            })
        .addOptionsModification(
            options -> {
              assertFalse(options.horizontalClassMergerOptions().isInterfaceMergingEnabled());
              options.horizontalClassMergerOptions().enableInterfaceMerging();
            })
        .enableInliningAnnotations()
        .enableNeverClassInliningAnnotations()
        .enableNoHorizontalClassMergingAnnotations()
        .enableNoUnusedInterfaceRemovalAnnotations()
        .enableNoVerticalClassMergingAnnotations()
        .setMinApi(parameters.getApiLevel())
        .compile()
        .inspect(
            inspector -> {
              ClassSubject aClassSubject = inspector.clazz(A.class);
              assertThat(aClassSubject, isPresent());
              assertThat(aClassSubject, isImplementing(inspector.clazz(I.class)));
              assertThat(aClassSubject, isImplementing(inspector.clazz(K.class)));

              ClassSubject bClassSubject = inspector.clazz(C.class);
              assertThat(bClassSubject, isPresent());
              assertThat(
                  bClassSubject,
                  isImplementing(
                      inspector.clazz(
                          parameters.canUseDefaultAndStaticInterfaceMethods()
                              ? J.class
                              : I.class)));
            })
        .run(parameters.getRuntime(), Main.class)
        .assertSuccessWithOutputLines("A", "K", "J");
  }

  static class Main {

    public static void main(String[] args) {
      new A().keepA();
      new B().m();
      new C().m();
    }
  }

  @NoUnusedInterfaceRemoval
  @NoVerticalClassMerging
  interface I {}

  @NoUnusedInterfaceRemoval
  @NoVerticalClassMerging
  interface J {
    @NeverInline
    default void m() {
      System.out.println("J");
    }
  }

  @NoHorizontalClassMerging
  @NoUnusedInterfaceRemoval
  @NoVerticalClassMerging
  interface K {
    @NeverInline
    default void m() {
      System.out.println("K");
    }
  }

  @NeverClassInline
  static class A implements I {
    @NeverInline
    void keepA() {
      System.out.println("A");
    }
  }

  // Will be merged into A, which as a side effect contributes the default method K.m() to A.
  // This should prevent merging of J into I, since that would contribute the default method J.m()
  // to A.
  @NeverClassInline
  static class B implements K {}

  @NeverClassInline
  @NoHorizontalClassMerging
  static class C implements J {}
}