Make information about the Java runtime in use available in Skylark using a dependency.

RELNOTES: None.
PiperOrigin-RevId: 161504700

7 files changed, 173 insertions, 15 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
index 6a5c3d2b1d..f021bec6c8 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
@@ -519,8 +519,8 @@ public class BazelRuleClassProvider {
           builder.addRuleDefinition(new AndroidDeviceRule());
 
           builder.addSkylarkAccessibleTopLevels("android_common", new AndroidSkylarkCommon());
-          builder.addSkylarkAccessibleTopLevels(
-              "java_common", new JavaSkylarkCommon(BazelJavaSemantics.INSTANCE));
+          builder.addSkylarkAccessibleTopLevels("java_common", new JavaSkylarkCommon(
+              BazelJavaSemantics.INSTANCE, builder.getToolsRepository()));
           builder.addSkylarkAccessibleTopLevels("java_proto_common", JavaProtoSkylarkCommon.class);
 
           try {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntime.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntime.java
index 73f9f09c51..108edd055c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntime.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntime.java
@@ -73,6 +73,9 @@ public class JavaRuntime implements RuleConfiguredTargetFactory {
             .addTransitiveArtifacts(filesToBuild)
             .build();
 
+    JavaRuntimeProvider javaRuntime = new JavaRuntimeProvider(
+        filesToBuild, javaHome, javaBinaryExecPath, javaBinaryRunfilesPath);
+
     MakeVariableProvider makeVariableProvider = new MakeVariableProvider(ImmutableMap.of(
         "JAVA", javaBinaryExecPath.getPathString(),
         "JAVABASE", javaHome.getPathString()));
@@ -80,8 +83,8 @@ public class JavaRuntime implements RuleConfiguredTargetFactory {
     return new RuleConfiguredTargetBuilder(ruleContext)
         .addProvider(RunfilesProvider.class, RunfilesProvider.simple(runfiles))
         .setFilesToBuild(filesToBuild)
-        .addProvider(JavaRuntimeProvider.class, JavaRuntimeProvider.create(
-            filesToBuild, javaHome, javaBinaryExecPath, javaBinaryRunfilesPath))
+        .addProvider(JavaRuntimeProvider.class, javaRuntime)
+        .addNativeDeclaredProvider(javaRuntime)
         .addProvider(MiddlemanProvider.class, new MiddlemanProvider(middleman))
         .addProvider(makeVariableProvider)
         .addNativeDeclaredProvider(makeVariableProvider)
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProvider.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProvider.java
index 7df3efcb7a..33235a3d04 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProvider.java
@@ -14,34 +14,81 @@
 
 package com.google.devtools.build.lib.rules.java;
 
-import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.packages.ClassObjectConstructor;
+import com.google.devtools.build.lib.packages.NativeClassObjectConstructor;
+import com.google.devtools.build.lib.packages.SkylarkClassObject;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.vfs.PathFragment;
 
 /** Information about the Java runtime used by the <code>java_*</code> rules. */
-@AutoValue
+@SkylarkModule(
+    name = "JavaRuntimeInfo",
+    doc = "Information about the Java runtime being used."
+)
 @Immutable
-public abstract class JavaRuntimeProvider implements TransitiveInfoProvider {
+public class JavaRuntimeProvider extends SkylarkClassObject
+    implements TransitiveInfoProvider {
+  public static final String SKYLARK_NAME = "JavaRuntimeInfo";
 
-  public static JavaRuntimeProvider create(
+  public static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
+      new NativeClassObjectConstructor(JavaToolchainProvider.class, SKYLARK_NAME) {};
+
+  private final NestedSet<Artifact> javaBaseInputs;
+  private final PathFragment javaHome;
+  private final PathFragment javaBinaryExecPath;
+  private final PathFragment javaBinaryRunfilesPath;
+
+  public JavaRuntimeProvider(
       NestedSet<Artifact> javaBaseInputs, PathFragment javaHome,
       PathFragment javaBinaryExecPath, PathFragment javaBinaryRunfilesPath) {
-    return new AutoValue_JavaRuntimeProvider(
-        javaBaseInputs, javaHome, javaBinaryExecPath, javaBinaryRunfilesPath);
+    super(SKYLARK_CONSTRUCTOR, ImmutableMap.<String, Object>of());
+    this.javaBaseInputs = javaBaseInputs;
+    this.javaHome = javaHome;
+    this.javaBinaryExecPath = javaBinaryExecPath;
+    this.javaBinaryRunfilesPath = javaBinaryRunfilesPath;
   }
 
   /** All input artifacts in the javabase. */
-  public abstract NestedSet<Artifact> javaBaseInputs();
+  public NestedSet<Artifact> javaBaseInputs() {
+    return javaBaseInputs;
+  }
 
   /** The root directory of the Java installation. */
-  public abstract PathFragment javaHome();
+  public PathFragment javaHome() {
+    return javaHome;
+  }
 
+  @SkylarkCallable(
+      name = "java_executable_exec_path",
+      doc = "Returns the execpath of the Java executable.",
+      structField = true
+  )
   /** The execpath of the Java binary. */
-  public abstract PathFragment javaBinaryExecPath();
+  public PathFragment javaBinaryExecPath() {
+    return javaBinaryExecPath;
+  }
 
   /** The runfiles path of the Java binary. */
-  public abstract PathFragment javaBinaryRunfilesPath();
+  public PathFragment javaBinaryRunfilesPath() {
+    return javaBinaryRunfilesPath;
+  }
+
+  // Not all of JavaRuntimeProvider is exposed to Skylark, which makes implementing deep equality
+  // impossible: if Java-only parts are considered, the behavior is surprising in Skylark, if they
+  // are not, the behavior is surprising in Java. Thus, object identity it is.
+  @Override
+  public boolean equals(Object other) {
+    return other == this;
+  }
+
+  @Override
+  public int hashCode() {
+    return System.identityHashCode(this);
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeSuite.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeSuite.java
index dfde6fd937..cab0d2c481 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeSuite.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeSuite.java
@@ -35,14 +35,17 @@ public class JavaRuntimeSuite implements RuleConfiguredTargetFactory {
     if (runtime == null) {
       runtime = ruleContext.getPrerequisite("default", Mode.TARGET);
     }
+
     if (runtime == null) {
       ruleContext.throwWithRuleError(
           "could not resolve runtime for cpu " + ruleContext.getConfiguration().getCpu());
     }
 
     MakeVariableProvider makeVariableProvider = runtime.getProvider(MakeVariableProvider.class);
+
     return new RuleConfiguredTargetBuilder(ruleContext)
         .addProvider(JavaRuntimeProvider.class, runtime.getProvider(JavaRuntimeProvider.class))
+        .addNativeDeclaredProvider(runtime.get(JavaRuntimeProvider.SKYLARK_CONSTRUCTOR.getKey()))
         .addProvider(RunfilesProvider.class, runtime.getProvider(RunfilesProvider.class))
         .addProvider(MiddlemanProvider.class, runtime.getProvider(MiddlemanProvider.class))
         .addProvider(makeVariableProvider)
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java
index 7ac14a5c4e..4d3359161c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.rules.java;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.MiddlemanProvider;
 import com.google.devtools.build.lib.analysis.RuleContext;
@@ -24,7 +25,10 @@ import com.google.devtools.build.lib.analysis.config.BuildConfiguration.StrictDe
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
+import com.google.devtools.build.lib.packages.Attribute;
+import com.google.devtools.build.lib.packages.BuildType;
 import com.google.devtools.build.lib.packages.ClassObjectConstructor;
+import com.google.devtools.build.lib.rules.SkylarkAttr;
 import com.google.devtools.build.lib.rules.SkylarkRuleContext;
 import com.google.devtools.build.lib.rules.java.proto.StrictDepsUtils;
 import com.google.devtools.build.lib.skylarkinterface.Param;
@@ -40,9 +44,11 @@ import java.util.List;
 @SkylarkModule(name = "java_common", doc = "Utilities for Java compilation support in Skylark.")
 public class JavaSkylarkCommon {
   private final JavaSemantics javaSemantics;
+  private final String toolsRepository;
 
-  public JavaSkylarkCommon(JavaSemantics javaSemantics) {
+  public JavaSkylarkCommon(JavaSemantics javaSemantics, String toolsrepository) {
     this.javaSemantics = javaSemantics;
+    this.toolsRepository = toolsrepository;
   }
 
   @SkylarkCallable(
@@ -452,4 +458,30 @@ public class JavaSkylarkCommon {
                 + " Only OFF and ERROR values are accepted.");
     }
   }
+
+  @SkylarkCallable(
+      name = JavaRuntimeProvider.SKYLARK_NAME,
+      doc = "The key used to retrieve the provider that contains information about the Java "
+          + "runtime being used.",
+      structField = true
+  )
+  public static ClassObjectConstructor getJavaRuntimeProvider() {
+    return JavaRuntimeProvider.SKYLARK_CONSTRUCTOR;
+  }
+
+  @SkylarkCallable(
+      name = "java_runtime_attr",
+      doc = "A value that, when passed as a value in the attribute dictionary of a rule "
+          + "definition, will yield a dependency that describes the current Java runtime in use.",
+      documented = false,
+      structField = true
+  )
+  public SkylarkAttr.Descriptor getJvmAttribute() {
+    ConfiguredRuleClassProvider.Builder env = new ConfiguredRuleClassProvider.Builder();
+    env.setToolsRepository(toolsRepository);
+    return new SkylarkAttr.Descriptor(
+        "java_runtime_attr",
+        new Attribute.Builder<>("", BuildType.LABEL)
+            .value(JavaSemantics.jvmAttribute(env)));
+  }
 }
diff --git a/src/test/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProviderTest.java b/src/test/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProviderTest.java
new file mode 100644
index 0000000000..750390dd5d
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/rules/java/JavaRuntimeProviderTest.java
@@ -0,0 +1,48 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.rules.java;
+
+import com.google.common.testing.EqualsTester;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.collect.nestedset.Order;
+import com.google.devtools.build.lib.vfs.PathFragment;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/**
+ * Unit tests for {@code JavaRuntimeProvider}
+ */
+@RunWith(JUnit4.class)
+public class JavaRuntimeProviderTest {
+  @Test
+  public void equalityIsObjectIdentity() {
+    JavaRuntimeProvider a = new JavaRuntimeProvider(
+        NestedSetBuilder.emptySet(Order.STABLE_ORDER),
+        PathFragment.create(""),
+        PathFragment.create(""),
+        PathFragment.create(""));
+    JavaRuntimeProvider b = new JavaRuntimeProvider(
+        NestedSetBuilder.emptySet(Order.STABLE_ORDER),
+        PathFragment.create(""),
+        PathFragment.create(""),
+        PathFragment.create(""));
+
+    new EqualsTester()
+        .addEqualityGroup(a)
+        .addEqualityGroup(b)
+        .testEquals();
+  }
+}
diff --git a/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java b/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java
index f594ca2cfd..b16dd4e24e 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java
@@ -28,6 +28,7 @@ import com.google.devtools.build.lib.packages.SkylarkClassObjectConstructor.Skyl
 import com.google.devtools.build.lib.rules.java.JavaRuleOutputJarsProvider.OutputJar;
 import com.google.devtools.build.lib.syntax.SkylarkList;
 import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
+import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
@@ -43,6 +44,30 @@ import org.junit.runners.JUnit4;
 public class JavaSkylarkApiTest extends BuildViewTestCase {
 
   @Test
+  public void testJavaRuntimeProvider() throws Exception {
+    scratch.file("a/BUILD",
+        "load(':rule.bzl', 'jrule')",
+        "java_runtime(name='jvm', srcs=[], java_home='/foo/bar/')",
+        "java_runtime_suite(name='suite', default=':jvm')",
+        "jrule(name='r')");
+
+    scratch.file(
+        "a/rule.bzl",
+        "def _impl(ctx):",
+        "  provider = ctx.attr._java_runtime[java_common.JavaRuntimeInfo]",
+        "  return struct(",
+        "    java_executable = provider.java_executable_exec_path,",
+        ")",
+        "jrule = rule(_impl, attrs = { '_java_runtime': java_common.java_runtime_attr})");
+
+    useConfiguration("--javabase=//a:suite");
+    ConfiguredTarget ct = getConfiguredTarget("//a:r");
+    @SuppressWarnings("unchecked") PathFragment javaExecutable =
+        (PathFragment) ct.get("java_executable");
+    assertThat(javaExecutable.getPathString()).startsWith("/foo/bar/bin/java");
+  }
+
+  @Test
   public void testExposesJavaSkylarkApiProvider() throws Exception {
     scratch.file(
         "java/test/BUILD",