Integrate starlark options with select() via the flag_values attribut…

…e of config_setting.

This includes adding an implicit provider to every build setting rule that knows its type and its default value.

PiperOrigin-RevId: 247508938

src/main/java/com/google/devtools/build/lib/analysis/BuildSettingProvider.java

@@ -0,0 +1,48 @@
+// Copyright 2019 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.analysis;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.devtools.build.lib.packages.BuildSetting;
+import com.google.devtools.build.lib.packages.RequiredProviders;
+import com.google.devtools.build.lib.syntax.Type;
+
+/**
+ * A native provider to allow select()s to know the type and default value when selecting on build
+ * settings
+ */
+public class BuildSettingProvider implements TransitiveInfoProvider {
+
+  public static final RequiredProviders REQUIRE_BUILD_SETTING_PROVIDER =
+      RequiredProviders.acceptAnyBuilder()
+          .addNativeSet(ImmutableSet.of(BuildSettingProvider.class))
+          .build();
+
+  private final BuildSetting buildSetting;
+  private final Object defaultValue;
+
+  public BuildSettingProvider(BuildSetting buildSetting, Object defaultValue) {
+    this.buildSetting = buildSetting;
+    this.defaultValue = defaultValue;
+  }
+
+  public Type<?> getType() {
+    return buildSetting.getType();
+  }
+
+  public Object getDefaultValue() {
+    return defaultValue;
+  }
+}

src/main/java/com/google/devtools/build/lib/analysis/RuleConfiguredTargetBuilder.java

@@ -14,6 +14,7 @@
 package com.google.devtools.build.lib.analysis;
 
 import static com.google.devtools.build.lib.analysis.ExtraActionUtils.createExtraActionProvider;
+import static com.google.devtools.build.lib.packages.RuleClass.Builder.SKYLARK_BUILD_SETTING_DEFAULT_ATTR_NAME;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
@@ -44,6 +45,7 @@
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.packages.BuildSetting;
 import com.google.devtools.build.lib.packages.InfoInterface;
 import com.google.devtools.build.lib.packages.NativeProvider;
 import com.google.devtools.build.lib.packages.Provider;
@@ -184,6 +186,15 @@ public ConfiguredTarget build() throws ActionConflictException {
       }
     }
 
+    if (ruleContext.getRule().isBuildSetting()) {
+      BuildSetting buildSetting = ruleContext.getRule().getRuleClassObject().getBuildSetting();
+      Object defaultValue =
+          ruleContext
+              .attributes()
+              .get(SKYLARK_BUILD_SETTING_DEFAULT_ATTR_NAME, buildSetting.getType());
+      addProvider(BuildSettingProvider.class, new BuildSettingProvider(buildSetting, defaultValue));
+    }
+
     TransitiveInfoProviderMap providers = providersBuilder.build();
 
     if (ruleContext.getRule().isAnalysisTest()) {

src/main/java/com/google/devtools/build/lib/analysis/config/StarlarkDefinedConfigTransition.java

@@ -74,6 +74,7 @@ public List<String> getInputs() {
   public List<String> getOutputs() {
     return outputs;
   }
+
 
   /**
    * Returns the location of the Starlark code responsible for determining the transition's changed

src/main/java/com/google/devtools/build/lib/analysis/skylark/StarlarkRuleTransitionProvider.java

@@ -79,7 +79,6 @@ class FunctionPatchTransition extends StarlarkTransition implements PatchTransit
     FunctionPatchTransition(
         StarlarkDefinedConfigTransition starlarkDefinedConfigTransition, Rule rule) {
       super(starlarkDefinedConfigTransition);
-
       LinkedHashMap<String, Object> attributes = new LinkedHashMap<>();
       RawAttributeMapper attributeMapper = RawAttributeMapper.of(rule);
       for (Attribute attribute : rule.getAttributes()) {

src/main/java/com/google/devtools/build/lib/packages/Rule.java

@@ -195,6 +195,10 @@ public boolean hasAnalysisTestTransition() {
     return ruleClass.hasAnalysisTestTransition();
   }
 
+  public boolean isBuildSetting() {
+    return ruleClass.getBuildSetting() != null;
+  }
+
   /**
    * Returns true iff there were errors while constructing this rule, such as
    * attributes with missing values or values of the wrong type.

src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagProvider.java

@@ -16,11 +16,13 @@
 
 import com.google.common.base.Predicate;
 import com.google.common.base.Predicates;
+import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.NativeInfo;
 import com.google.devtools.build.lib.packages.NativeProvider;
+import com.google.devtools.build.lib.packages.RequiredProviders;
 import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
 import com.google.devtools.build.lib.skylarkbuildapi.config.ConfigFeatureFlagProviderApi;
 import com.google.devtools.build.lib.syntax.Environment;
@@ -37,6 +39,9 @@ public class ConfigFeatureFlagProvider extends NativeInfo implements ConfigFeatu
   /** Skylark constructor and identifier for ConfigFeatureFlagProvider. */
   static final NativeProvider<ConfigFeatureFlagProvider> SKYLARK_CONSTRUCTOR = new Constructor();
 
+  static final RequiredProviders REQUIRE_CONFIG_FEATURE_FLAG_PROVIDER =
+      RequiredProviders.acceptAnyBuilder().addSkylarkSet(ImmutableSet.of(id())).build();
+
   private final String value;
   private final Predicate<String> validityPredicate;
 

src/main/java/com/google/devtools/build/lib/rules/config/ConfigRuleClasses.java

@@ -238,7 +238,6 @@ <li>Its syntax (<code>--define KEY=VAL</code>) means <code>KEY=VAL</code> is
               attr(FLAG_SETTINGS_ATTRIBUTE, LABEL_KEYED_STRING_DICT)
                   .undocumented("the feature flag feature has not yet been launched")
                   .allowedFileTypes()
-                  .mandatoryProviders(ImmutableList.of(ConfigFeatureFlagProvider.id()))
                   .nonconfigurable(NONCONFIGURABLE_ATTRIBUTE_REASON))
           /* <!-- #BLAZE_RULE(config_setting).ATTRIBUTE(constraint_values) -->
           The minimum set of <code>constraint_values</code> that the target platform must specify

src/main/java/com/google/devtools/build/lib/rules/config/ConfigSetting.java

@@ -29,6 +29,7 @@
 import com.google.common.collect.Multiset;
 import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
 import com.google.devtools.build.lib.analysis.AliasProvider;
+import com.google.devtools.build.lib.analysis.BuildSettingProvider;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
@@ -57,6 +58,7 @@
 import com.google.devtools.build.lib.packages.RuleErrorConsumer;
 import com.google.devtools.build.lib.rules.config.ConfigRuleClasses.ConfigSettingRule;
 import com.google.devtools.build.lib.syntax.Type;
+import com.google.devtools.build.lib.syntax.Type.ConversionException;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsParsingException;
@@ -108,16 +110,17 @@ public ConfiguredTarget create(RuleContext ruleContext)
       return null;
     }
 
+    TransitiveOptionDetails optionDetails =
+        BuildConfigurationOptionDetails.get(ruleContext.getConfiguration());
+
     boolean nativeFlagsMatch =
-        matchesConfig(
-            nativeFlagSettings.entries(),
-            BuildConfigurationOptionDetails.get(ruleContext.getConfiguration()),
-            ruleContext);
+        matchesConfig(nativeFlagSettings.entries(), optionDetails, ruleContext);
 
-    ConfigFeatureFlagMatch featureFlags =
-        ConfigFeatureFlagMatch.fromAttributeValueAndPrerequisites(
+    UserDefinedFlagMatch userDefinedFlags =
+        UserDefinedFlagMatch.fromAttributeValueAndPrerequisites(
             userDefinedFlagSettings,
             ruleContext.getPrerequisites(ConfigSettingRule.FLAG_SETTINGS_ATTRIBUTE, Mode.TARGET),
+            optionDetails,
             ruleContext);
 
     boolean constraintValuesMatch = constraintValuesMatch(ruleContext);
@@ -130,8 +133,8 @@ public ConfiguredTarget create(RuleContext ruleContext)
         new ConfigMatchingProvider(
             ruleContext.getLabel(),
             nativeFlagSettings,
-            featureFlags.getSpecifiedFlagValues(),
-            nativeFlagsMatch && featureFlags.matches() && constraintValuesMatch);
+            userDefinedFlags.getSpecifiedFlagValues(),
+            nativeFlagsMatch && userDefinedFlags.matches() && constraintValuesMatch);
 
     return new RuleConfiguredTargetBuilder(ruleContext)
         .addProvider(RunfilesProvider.class, RunfilesProvider.EMPTY)
@@ -368,14 +371,13 @@ private static boolean optionMatches(
     return actualList.contains(expectedSingleValue);
   }
 
-  private static final class ConfigFeatureFlagMatch {
+  private static final class UserDefinedFlagMatch {
     private final boolean matches;
     private final ImmutableMap<Label, String> specifiedFlagValues;
 
     private static final Joiner QUOTED_COMMA_JOINER = Joiner.on("', '");
 
-    private ConfigFeatureFlagMatch(
-        boolean matches, ImmutableMap<Label, String> specifiedFlagValues) {
+    private UserDefinedFlagMatch(boolean matches, ImmutableMap<Label, String> specifiedFlagValues) {
       this.matches = matches;
       this.specifiedFlagValues = specifiedFlagValues;
     }
@@ -386,7 +388,7 @@ public boolean matches() {
     }
 
     /** Gets the specified flag values, with aliases converted to their original targets' labels. */
-    public ImmutableMap<Label, String> getSpecifiedFlagValues() {
+    ImmutableMap<Label, String> getSpecifiedFlagValues() {
       return specifiedFlagValues;
     }
 
@@ -401,20 +403,16 @@ private static ListMultimap<Label, Label> collectAliases(
       return targetsToAliases.build();
     }
 
-    public static ConfigFeatureFlagMatch fromAttributeValueAndPrerequisites(
+    static UserDefinedFlagMatch fromAttributeValueAndPrerequisites(
         Map<Label, String> attributeValue,
         Iterable<? extends TransitiveInfoCollection> prerequisites,
+        TransitiveOptionDetails optionDetails,
         RuleErrorConsumer errors) {
       Map<Label, String> specifiedFlagValues = new LinkedHashMap<>();
       boolean matches = true;
       boolean foundDuplicate = false;
 
       for (TransitiveInfoCollection target : prerequisites) {
-        ConfigFeatureFlagProvider provider = ConfigFeatureFlagProvider.fromTarget(target);
-        // We know the provider exists because only labels with ConfigFeatureFlagProvider can be
-        // added to this attribute.
-        assert provider != null;
-
         Label actualLabel = target.getLabel();
         Label specifiedLabel = AliasProvider.getDependencyLabel(target);
         String specifiedValue = attributeValue.get(specifiedLabel);
@@ -423,17 +421,52 @@ public static ConfigFeatureFlagMatch fromAttributeValueAndPrerequisites(
         }
         specifiedFlagValues.put(actualLabel, specifiedValue);
 
-        if (!provider.isValidValue(specifiedValue)) {
+        if (target.satisfies(ConfigFeatureFlagProvider.REQUIRE_CONFIG_FEATURE_FLAG_PROVIDER)) {
+          // config_feature_flag
+          ConfigFeatureFlagProvider provider = ConfigFeatureFlagProvider.fromTarget(target);
+          if (!provider.isValidValue(specifiedValue)) {
+            errors.attributeError(
+                ConfigSettingRule.FLAG_SETTINGS_ATTRIBUTE,
+                String.format(
+                    "error while parsing user-defined configuration values: "
+                        + "'%s' is not a valid value for '%s'",
+                    specifiedValue, specifiedLabel));
+            matches = false;
+            continue;
+          }
+          if (!provider.getFlagValue().equals(specifiedValue)) {
+            matches = false;
+          }
+        } else if (target.satisfies(BuildSettingProvider.REQUIRE_BUILD_SETTING_PROVIDER)) {
+          // build setting
+          BuildSettingProvider provider = target.getProvider(BuildSettingProvider.class);
+          Object configurationValue =
+              optionDetails.getOptionValue(specifiedLabel) != null
+                  ? optionDetails.getOptionValue(specifiedLabel)
+                  : provider.getDefaultValue();
+          Object convertedSpecifiedValue;
+          try {
+            convertedSpecifiedValue = provider.getType().convert(specifiedValue, specifiedLabel);
+          } catch (ConversionException e) {
+            errors.attributeError(
+                ConfigSettingRule.FLAG_SETTINGS_ATTRIBUTE,
+                String.format(
+                    "error while parsing user-defined configuration values: "
+                        + "'%s' cannot be converted to %s type %s",
+                    specifiedValue, specifiedLabel, provider.getType()));
+            matches = false;
+            continue;
+          }
+          if (!configurationValue.equals(convertedSpecifiedValue)) {
+            matches = false;
+          }
+        } else {
           errors.attributeError(
               ConfigSettingRule.FLAG_SETTINGS_ATTRIBUTE,
               String.format(
                   "error while parsing user-defined configuration values: "
-                      + "'%s' is not a valid value for '%s'",
-                  specifiedValue, specifiedLabel));
-          matches = false;
-          continue;
-        }
-        if (!provider.getFlagValue().equals(specifiedValue)) {
+                      + "%s keys must be build settings or feature flags and %s is not",
+                  ConfigSettingRule.FLAG_SETTINGS_ATTRIBUTE, specifiedLabel));
           matches = false;
         }
       }
@@ -454,11 +487,10 @@ public static ConfigFeatureFlagMatch fromAttributeValueAndPrerequisites(
                     actualLabel, QUOTED_COMMA_JOINER.join(aliasList)));
           }
         }
-
         matches = false;
       }
 
-      return new ConfigFeatureFlagMatch(matches, ImmutableMap.copyOf(specifiedFlagValues));
+      return new UserDefinedFlagMatch(matches, ImmutableMap.copyOf(specifiedFlagValues));
     }
   }
 }