Skylark: In addition to using ctx.configuration.fragment(CONF), the build configuration can now be accessed via ctx.configuration.CONF where CONF is in {cpp, jvm, java}.

--
MOS_MIGRATED_REVID=99470271

6 files changed, 99 insertions, 10 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RuleConfiguredTargetBuilder.java b/src/main/java/com/google/devtools/build/lib/analysis/RuleConfiguredTargetBuilder.java
index 47d0eb3449..a4a830e7cd 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RuleConfiguredTargetBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RuleConfiguredTargetBuilder.java
@@ -396,7 +396,11 @@ public final class RuleConfiguredTargetBuilder {
         checkSkylarkObjectSafe(entry.getValue());
       }
       return;
-    } else if (object instanceof ClassObject) {
+    } else if (object instanceof ClassObject && !(object instanceof BuildConfiguration)) {
+      // We had to make BuildConfiguration implement ClassObject in order to allow access to
+      // individual fragments as fields.
+      // However, we don't want to expose it to the outside world, thus forcing us to add this
+      // explicit check here.
       ClassObject struct = (ClassObject) object;
       for (String key : struct.getKeys()) {
         checkSkylarkObjectSafe(struct.getValue(key));
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
index d613f1e37e..849b7785d2 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
@@ -19,6 +19,7 @@ import com.google.common.base.Function;
 import com.google.common.base.Joiner;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
@@ -44,6 +45,7 @@ import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.rules.test.TestActionBuilder;
+import com.google.devtools.build.lib.syntax.ClassObject;
 import com.google.devtools.build.lib.syntax.Label;
 import com.google.devtools.build.lib.syntax.Label.SyntaxException;
 import com.google.devtools.build.lib.syntax.SkylarkCallable;
@@ -106,7 +108,7 @@ import javax.annotation.Nullable;
 @SkylarkModule(name = "configuration",
     doc = "Data required for the analysis of a target that comes from targets that "
         + "depend on it and not targets that it depends on.")
-public final class BuildConfiguration {
+public final class BuildConfiguration implements ClassObject {
 
   /**
    * An interface for language-specific configurations.
@@ -194,6 +196,22 @@ public final class BuildConfiguration {
     }
 
     /**
+     * Determines whether this fragment can be accessed in Skylark as a field of
+     * ctx.configuration
+     */
+    public boolean isSkylarkVisible() {
+      return false;
+    }
+
+    /**
+     * If this fragment is skylarkVisible, it will be accessible in Skylark via
+     * ctx.configuration.NAME where NAME = getName()
+     */
+    public String getName() {
+      return getClass().getName();
+    }
+
+    /**
      * Returns a fragment of the output directory name for this configuration. The output
      * directory for the whole configuration contains all the short names by all fragments.
      */
@@ -874,6 +892,7 @@ public final class BuildConfiguration {
   private Set<BuildConfiguration> allReachableConfigurations;
 
   private final ImmutableMap<Class<? extends Fragment>, Fragment> fragments;
+  private final ImmutableMap<String, Fragment> skylarkVisibleFragments;
 
   /**
    * Directories in the output tree.
@@ -1033,6 +1052,8 @@ public final class BuildConfiguration {
     this.actionsEnabled = !actionsDisabled;
     this.fragments = ImmutableMap.copyOf(fragmentsMap);
 
+    this.skylarkVisibleFragments = buildIndexOfVisibleFragments();
+    
     this.buildOptions = buildOptions;
     this.options = buildOptions.get(Options.class);
 
@@ -1097,6 +1118,17 @@ public final class BuildConfiguration {
     checksum = Fingerprint.md5Digest(buildOptions.computeCacheKey());
   }
 
+  private ImmutableMap<String, Fragment> buildIndexOfVisibleFragments() {
+    ImmutableMap.Builder<String, Fragment> builder = ImmutableMap.builder();
+
+    for (Fragment fragment : fragments.values()) {
+      if (fragment.isSkylarkVisible()) {
+        builder.put(fragment.getName(), fragment);
+      }
+    }
+
+    return builder.build();
+  }
 
   /**
    * Computes and returns the transitive optionName -> "option info" map for
@@ -1610,7 +1642,7 @@ public final class BuildConfiguration {
   public String getMakeVariableDefault(String var) {
     return globalMakeEnv.get(var);
   }
-
+  
   /**
    * Returns a configuration fragment instances of the given class.
    */
@@ -1890,4 +1922,21 @@ public final class BuildConfiguration {
   public List<Label> getTargetEnvironments() {
     return options.targetEnvironments;
   }
+
+  @Override
+  @Nullable
+  public Object getValue(String name) {
+    return skylarkVisibleFragments.get(name);
+  }
+
+  @Override
+  public ImmutableCollection<String> getKeys() {
+    return skylarkVisibleFragments.keySet();
+  }
+
+  @Override
+  @Nullable
+  public String errorMessage(String name) {
+    return String.format("There is no configuration fragment named '%s'", name);
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index a32c11697b..6401d4e3d9 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -662,6 +662,16 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     this.additionalMakeVariables = ImmutableMap.copyOf(makeVariablesBuilder);
   }
 
+  @Override
+  public boolean isSkylarkVisible() {
+    return true;
+  }
+
+  @Override
+  public String getName() {
+    return "cpp";
+  }
+
   private List<OptionalFlag> convertOptionalOptions(
           List<CrosstoolConfig.CToolchain.OptionalFlag> optionalFlagList)
       throws IllegalArgumentException {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java
index 37137c9db1..71454c6ef5 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java
@@ -104,6 +104,16 @@ public final class JavaConfiguration extends Fragment {
     }
     this.translationTargets = translationsBuilder.build();
   }
+  
+  @Override
+  public boolean isSkylarkVisible() {
+    return true;
+  }
+
+  @Override
+  public String getName() {
+    return "java";
+  }
 
   @SkylarkCallable(name = "default_javac_flags", structField = true,
       doc = "The default flags for the Java compiler.")
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/Jvm.java b/src/main/java/com/google/devtools/build/lib/rules/java/Jvm.java
index d822da836c..378dc60462 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/Jvm.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/Jvm.java
@@ -46,6 +46,16 @@ public final class Jvm extends BuildConfiguration.Fragment {
     this.javaHome = javaHome;
     this.jvmLabel = jvmLabel;
   }
+  
+  @Override
+  public boolean isSkylarkVisible() {
+    return true;
+  }
+
+  @Override
+  public String getName() {
+    return "jvm";
+  }
 
   @Override
   public void addImplicitLabels(Multimap<String, Label> implicitLabels) {
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
index bb0e8ed54b..1b98a27aa5 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
@@ -71,14 +71,20 @@ public final class DotExpression extends Expression {
   public static Object eval(Object objValue, String name, Location loc) throws EvalException {
     if (objValue instanceof ClassObject) {
       Object result = ((ClassObject) objValue).getValue(name);
-      result = SkylarkType.convertToSkylark(result, loc);
-      // If we access NestedSets using ClassObject.getValue() we won't know the generic type,
-      // so we have to disable it. This should not happen.
-      SkylarkType.checkTypeAllowedInSkylark(result, loc);
-      return result;
+
+      // ClassObjects may have fields that are annotated with @SkylarkCallable.
+      // Since getValue() does not know about those, we cannot expect that result is a valid object.
+      if (result != null) {
+        result = SkylarkType.convertToSkylark(result, loc);
+        // If we access NestedSets using ClassObject.getValue() we won't know the generic type,
+        // so we have to disable it. This should not happen.
+        SkylarkType.checkTypeAllowedInSkylark(result, loc);
+        return result;
+      }
     }
-    List<MethodDescriptor> methods = FuncallExpression.getMethods(objValue.getClass(),
-          name, 0, loc);
+
+    List<MethodDescriptor> methods =
+        FuncallExpression.getMethods(objValue.getClass(), name, 0, loc);
     if (methods != null && !methods.isEmpty()) {
       MethodDescriptor method = Iterables.getOnlyElement(methods);
       if (method.getAnnotation().structField()) {