Add feature_flags attribute to Android binary rules.

This is the first actual user of the config_feature_flag rule, able to actually
set its value (and thus give a point to using it!)

This feature is not fully launched yet, but it is usable in any build
containing this change.

RELNOTES: None.
PiperOrigin-RevId: 152948153

6 files changed, 110 insertions, 6 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/BUILD b/src/main/java/com/google/devtools/build/lib/BUILD
index afbafdf117..cd90d661d8 100644
--- a/src/main/java/com/google/devtools/build/lib/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/BUILD
@@ -984,6 +984,7 @@ java_library(
         ":vfs",
         "//src/main/java/com/google/devtools/build/lib:skylarkinterface",
         "//src/main/java/com/google/devtools/build/lib/actions",
+        "//src/main/java/com/google/devtools/build/lib/rules/config",
         "//src/main/java/com/google/devtools/build/lib/rules/cpp",
         "//src/main/java/com/google/devtools/common/options",
         "//src/main/protobuf:android_deploy_info_java_proto",
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/android/BazelAndroidBinaryRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/android/BazelAndroidBinaryRule.java
index 8fedd68833..a5a4fe57d3 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/android/BazelAndroidBinaryRule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/android/BazelAndroidBinaryRule.java
@@ -25,7 +25,9 @@ import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.packages.RuleClass.Builder;
 import com.google.devtools.build.lib.rules.android.AndroidBinaryOnlyRule;
 import com.google.devtools.build.lib.rules.android.AndroidConfiguration;
+import com.google.devtools.build.lib.rules.android.AndroidFeatureFlagSetProvider;
 import com.google.devtools.build.lib.rules.android.AndroidRuleClasses;
+import com.google.devtools.build.lib.rules.config.ConfigFeatureFlagTransitionFactory;
 import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
 import com.google.devtools.build.lib.rules.cpp.CppRuleClasses;
 import com.google.devtools.build.lib.rules.java.JavaConfiguration;
@@ -82,6 +84,8 @@ public class BazelAndroidBinaryRule implements RuleDefinition {
         </ul>
         <!-- #END_BLAZE_RULE.IMPLICIT_OUTPUTS --> */
         .setImplicitOutputsFunction(AndroidRuleClasses.ANDROID_BINARY_IMPLICIT_OUTPUTS)
+        .cfg(
+            new ConfigFeatureFlagTransitionFactory(AndroidFeatureFlagSetProvider.FEATURE_FLAG_ATTR))
         .build();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java
index 655d546568..29dad5109b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java
@@ -809,7 +809,7 @@ public abstract class AndroidBinary implements RuleConfiguredTargetFactory {
 
     return builder
         .setFilesToBuild(filesToBuild)
-        .add(
+        .addProvider(
             RunfilesProvider.class,
             RunfilesProvider.simple(
                 new Runfiles.Builder(
@@ -818,16 +818,20 @@ public abstract class AndroidBinary implements RuleConfiguredTargetFactory {
                     .addRunfiles(ruleContext, RunfilesProvider.DEFAULT_RUNFILES)
                     .addTransitiveArtifacts(filesToBuild)
                     .build()))
-        .add(
+        .addProvider(
             JavaSourceInfoProvider.class,
             JavaSourceInfoProvider.fromJavaTargetAttributes(resourceClasses, javaSemantics))
-        .add(
+        .addProvider(
             ApkProvider.class,
             ApkProvider.create(
                 NestedSetBuilder.create(Order.STABLE_ORDER, zipAlignedApk),
                 coverageMetadata,
                 NestedSetBuilder.create(Order.STABLE_ORDER, applicationManifest.getManifest())))
-        .add(AndroidPreDexJarProvider.class, AndroidPreDexJarProvider.create(jarToDex))
+        .addProvider(AndroidPreDexJarProvider.class, AndroidPreDexJarProvider.create(jarToDex))
+        .addProvider(
+            AndroidFeatureFlagSetProvider.class,
+            AndroidFeatureFlagSetProvider.create(
+                AndroidFeatureFlagSetProvider.getAndValidateFlagMapFromRuleContext(ruleContext)))
         .addOutputGroup("mobile_install_full" + INTERNAL_SUFFIX, fullInstallOutputGroup)
         .addOutputGroup(
             "mobile_install_incremental" + INTERNAL_SUFFIX, incrementalInstallOutputGroup)
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidFeatureFlagSetProvider.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidFeatureFlagSetProvider.java
new file mode 100644
index 0000000000..315aea19c6
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidFeatureFlagSetProvider.java
@@ -0,0 +1,82 @@
+// 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.android;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.packages.BuildType;
+import com.google.devtools.build.lib.packages.NonconfigurableAttributeMapper;
+import com.google.devtools.build.lib.packages.RuleClass.ConfiguredTargetFactory.RuleErrorException;
+import com.google.devtools.build.lib.rules.config.ConfigFeatureFlagProvider;
+import java.util.Map;
+
+/**
+ * Provider for checking the set of feature flags used by an android_binary.
+ *
+ * <p>Because the feature flags are completely replaced by android_binary, android_test uses this
+ * provider to ensure that the test sets the same flags as the binary. Otherwise, the dependencies
+ * of the android_test will be compiled with different flags from the android_binary code which runs
+ * in the same Android virtual machine, which may cause compatibility issues at runtime.
+ */
+@AutoValue
+@Immutable
+public abstract class AndroidFeatureFlagSetProvider implements TransitiveInfoProvider {
+
+  /** The name of the attribute used by Android rules to set config_feature_flags. */
+  public static final String FEATURE_FLAG_ATTR = "feature_flags";
+
+  AndroidFeatureFlagSetProvider() {}
+
+  /** Creates a new AndroidFeatureFlagSetProvider with the given flags. */
+  public static AndroidFeatureFlagSetProvider create(Map<Label, String> flags) {
+    return new AutoValue_AndroidFeatureFlagSetProvider(ImmutableMap.copyOf(flags));
+  }
+
+  /**
+   * Builds a map which can be used with create, confirming that the desired flag values were
+   * actually received, and producing an error if they were not (because dynamic configurations are
+   * not enabled).
+   */
+  public static ImmutableMap<Label, String> getAndValidateFlagMapFromRuleContext(
+      RuleContext ruleContext) throws RuleErrorException {
+    Map<Label, String> expectedValues =
+        NonconfigurableAttributeMapper.of(ruleContext.getRule())
+            .get(FEATURE_FLAG_ATTR, BuildType.LABEL_KEYED_STRING_DICT);
+    Iterable<? extends TransitiveInfoCollection> actualTargets =
+        ruleContext.getPrerequisites(FEATURE_FLAG_ATTR, Mode.TARGET);
+    for (TransitiveInfoCollection target : actualTargets) {
+      Label label = target.getLabel();
+      String expectedValue = expectedValues.get(label);
+      String actualValue = ConfigFeatureFlagProvider.fromTarget(target).getValue();
+
+      if (!expectedValue.equals(actualValue)) {
+        // TODO(mstaib): when static configurations are removed, remove this error case
+        ruleContext.attributeError(
+            FEATURE_FLAG_ATTR,
+            "Setting " + FEATURE_FLAG_ATTR + " requires dynamic configurations to be enabled");
+        throw new RuleErrorException();
+      }
+    }
+    return ImmutableMap.copyOf(expectedValues);
+  }
+
+  public abstract ImmutableMap<Label, String> getFlags();
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
index 7a05c36d0c..7c289e3ccb 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.rules.android;
 import static com.google.devtools.build.lib.packages.Attribute.ConfigurationTransition.HOST;
 import static com.google.devtools.build.lib.packages.Attribute.attr;
 import static com.google.devtools.build.lib.packages.BuildType.LABEL;
+import static com.google.devtools.build.lib.packages.BuildType.LABEL_KEYED_STRING_DICT;
 import static com.google.devtools.build.lib.packages.BuildType.LABEL_LIST;
 import static com.google.devtools.build.lib.packages.BuildType.TRISTATE;
 import static com.google.devtools.build.lib.packages.ImplicitOutputsFunction.fromTemplates;
@@ -46,6 +47,7 @@ import com.google.devtools.build.lib.packages.RuleClass.Builder;
 import com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType;
 import com.google.devtools.build.lib.packages.TriState;
 import com.google.devtools.build.lib.rules.android.AndroidConfiguration.ConfigurationDistinguisher;
+import com.google.devtools.build.lib.rules.config.ConfigFeatureFlagProvider;
 import com.google.devtools.build.lib.rules.cpp.CppOptions;
 import com.google.devtools.build.lib.rules.java.JavaCompilationArgsProvider;
 import com.google.devtools.build.lib.rules.java.JavaConfiguration;
@@ -795,6 +797,12 @@ public final class AndroidRuleClasses {
           Rex suggests an updated package map that can be saved and reused for subsequent builds.
            */
           .add(attr("rex_package_map", LABEL).legacyAllowAnyFileType().undocumented("experimental"))
+          .add(attr(AndroidFeatureFlagSetProvider.FEATURE_FLAG_ATTR, LABEL_KEYED_STRING_DICT)
+              .undocumented("the feature flag feature has not yet been launched")
+              .allowedRuleClasses("config_feature_flag")
+              .allowedFileTypes()
+              .nonconfigurable("defines an aspect of configuration")
+              .mandatoryProviders(ImmutableList.of(ConfigFeatureFlagProvider.SKYLARK_IDENTIFIER)))
           .advertiseProvider(JavaCompilationArgsProvider.class)
           .build();
       }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagProvider.java b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagProvider.java
index 1bc6481234..265388eb1f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagProvider.java
@@ -46,8 +46,13 @@ public abstract class ConfigFeatureFlagProvider extends SkylarkClassObject
   static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
       new NativeClassObjectConstructor(SKYLARK_NAME) {};
 
-  /** Identifier used to retrieve this provider from rules which export it. */
-  static final SkylarkProviderIdentifier SKYLARK_IDENTIFIER =
+  /**
+   * Identifier used to retrieve this provider from rules which export it.
+   *
+   * <p>Prefer to use {@link #fromTarget(TransitiveInfoCollection)} for the purposes of getting this
+   * provider from a TransitiveInfoCollection; this should be used for mandatoryProviders only.
+   */
+  public static final SkylarkProviderIdentifier SKYLARK_IDENTIFIER =
       SkylarkProviderIdentifier.forKey(SKYLARK_CONSTRUCTOR.getKey());
 
   ConfigFeatureFlagProvider() {