Create a new output formatter for cquery which output transition information in either a FULL or LITE version. Trigger new output with the new --transitions cquery flag in the new CqueryOptions class.

PiperOrigin-RevId: 190278664

10 files changed, 443 insertions, 33 deletions

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 54e7468ad5..56e54a37a9 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
@@ -1390,7 +1390,7 @@ public class BuildConfiguration {
     globalMakeEnvBuilder.put("GENDIR", getGenfilesDirectory().getExecPath().getPathString());
     globalMakeEnv = globalMakeEnvBuilder.build();
 
-    checksum = Fingerprint.md5Digest(buildOptions.computeCacheKey());
+    checksum = computeChecksum(buildOptions);
     hashCode = computeHashCode();
 
     ImmutableSet.Builder<String> reservedActionMnemonics = ImmutableSet.builder();
@@ -1401,6 +1401,10 @@ public class BuildConfiguration {
     this.buildEventSupplier = Suppliers.memoize(this::createBuildEvent);
   }
 
+  public static String computeChecksum(BuildOptions buildOptions) {
+    return Fingerprint.md5Digest(buildOptions.computeCacheKey());
+  }
+
   /**
    * Returns a copy of this configuration only including the given fragments (which the current
    * configuration is assumed to have).
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
index c4ce4e5ea3..d84db4ce32 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
@@ -21,12 +21,14 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSortedMap;
+import com.google.common.collect.Iterables;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.Sets;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.runtime.proto.InvocationPolicyOuterClass.InvocationPolicy;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
 import com.google.devtools.build.lib.util.Fingerprint;
+import com.google.devtools.build.lib.util.OrderedSetMultimap;
 import com.google.devtools.common.options.InvocationPolicyEnforcer;
 import com.google.devtools.common.options.OptionDefinition;
 import com.google.devtools.common.options.OptionsBase;
@@ -34,11 +36,13 @@ import com.google.devtools.common.options.OptionsClassProvider;
 import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsParsingException;
 import java.io.Serializable;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -344,16 +348,32 @@ public final class BuildOptions implements Cloneable, Serializable {
     }
   }
 
-  /** Returns the difference between two BuildOptions in a {@link BuildOptions.OptionsDiff}. */
-  public static OptionsDiff diff(BuildOptions first, BuildOptions second) {
+  /** Returns the difference between two BuildOptions in a new {@link BuildOptions.OptionsDiff}. */
+  public static OptionsDiff diff(@Nullable BuildOptions first, @Nullable BuildOptions second) {
+    return diff(new OptionsDiff(), first, second);
+  }
+
+  /**
+   * Returns the difference between two BuildOptions in a pre-existing {@link
+   * BuildOptions.OptionsDiff}.
+   *
+   * <p>In a single pass through this method, the method can only compare a single "first" {@link
+   * BuildOptions} and single "second" BuildOptions; but an OptionsDiff instance can store the diff
+   * between a single "first" BuildOptions and multiple "second" BuildOptions. Being able to
+   * maintain a single OptionsDiff over multiple calls to diff is useful for, for example,
+   * aggregating the difference between a single BuildOptions and the results of applying a {@link
+   * com.google.devtools.build.lib.analysis.config.transitions.SplitTransition}) to it.
+   */
+  public static OptionsDiff diff(
+      OptionsDiff diff, @Nullable BuildOptions first, @Nullable BuildOptions second) {
     if (first == null || second == null) {
       throw new IllegalArgumentException("Cannot diff null BuildOptions");
     }
-    OptionsDiff diff = new OptionsDiff();
     if (first.equals(second)) {
       return diff;
     }
-    // Check if either class has been trimmed of an options class that exists in the other.
+    // Check and report if either class has been trimmed of an options class that exists in the
+    // other.
     ImmutableSet<Class<? extends FragmentOptions>> firstOptionClasses =
         first.getOptions()
             .stream()
@@ -405,7 +425,17 @@ public final class BuildOptions implements Cloneable, Serializable {
       Collection<OptionDefinition> fields = diff.differingOptions.get(clazz);
       HashMap<String, Object> valueMap = new HashMap<>(fields.size());
       for (OptionDefinition optionDefinition : fields) {
-        Object secondValue = diff.second.get(optionDefinition);
+        Object secondValue;
+        try {
+          secondValue = Iterables.getOnlyElement(diff.second.get(optionDefinition));
+        } catch (IllegalArgumentException e) {
+          // TODO(janakr): Currently this exception should never be thrown since diff is never
+          // constructed using the diff method that takes in a preexisting OptionsDiff. If this
+          // changes, add a test verifying this error catching works properly.
+          throw new IllegalStateException(
+              "OptionsDiffForReconstruction can only handle a single first BuildOptions and a "
+                  + "single second BuildOptions and has encountered multiple second BuildOptions");
+        }
         valueMap.put(optionDefinition.getField().getName(), secondValue);
       }
       differingOptions.put(clazz, valueMap);
@@ -419,14 +449,20 @@ public final class BuildOptions implements Cloneable, Serializable {
   }
 
   /**
-   * A diff class for BuildOptions. Fields are meant to be populated and returned by
-   * {@link BuildOptions#diff}
+   * A diff class for BuildOptions. Fields are meant to be populated and returned by {@link
+   * BuildOptions#diff}
    */
   public static class OptionsDiff{
     private final Multimap<Class<? extends FragmentOptions>, OptionDefinition> differingOptions =
         ArrayListMultimap.create();
-    private final Map<OptionDefinition, Object> first = new HashMap<>();
-    private final Map<OptionDefinition, Object> second = new HashMap<>();
+    // The keyset for the {@link first} and {@link second} maps are identical and indicate which
+    // specific options differ between the first and second built options.
+    private final Map<OptionDefinition, Object> first = new LinkedHashMap<>();
+    // Since this class can be used to track the result of transitions, {@link second} is a multimap
+    // to be able to handle [@link SplitTransition}s.
+    private final Multimap<OptionDefinition, Object> second = OrderedSetMultimap.create();
+    // List of "extra" fragments for each BuildOption aka fragments that were trimmed off one
+    // BuildOption but not the other.
     private final Set<Class<? extends FragmentOptions>> extraFirstFragments = new HashSet<>();
     private final Set<FragmentOptions> extraSecondFragments = new HashSet<>();
 
@@ -452,7 +488,7 @@ public final class BuildOptions implements Cloneable, Serializable {
       return first;
     }
 
-    public Map<OptionDefinition, Object> getSecond() {
+    public Multimap<OptionDefinition, Object> getSecond() {
       return second;
     }
 
@@ -480,17 +516,20 @@ public final class BuildOptions implements Cloneable, Serializable {
 
     public String prettyPrint() {
       StringBuilder toReturn = new StringBuilder();
-      for (Map.Entry<OptionDefinition, Object> firstOption : first.entrySet()) {
-        toReturn
-            .append(firstOption.getKey().getOptionName())
-            .append(":")
-            .append(firstOption.getValue())
-            .append(" -> ")
-            .append(second.get(firstOption.getKey()))
-            .append(System.lineSeparator());
+      for (String diff : getPrettyPrintList()) {
+        toReturn.append(diff).append(System.lineSeparator());
       }
       return toReturn.toString();
     }
+
+    public List<String> getPrettyPrintList() {
+      List<String> toReturn = new ArrayList<>();
+        first.forEach(
+            (option, value) ->
+                toReturn.add(
+                    option.getOptionName() + ":" + value + " -> " + second.get(option)));
+      return toReturn;
+    }
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/buildtool/CqueryBuildTool.java b/src/main/java/com/google/devtools/build/lib/buildtool/CqueryBuildTool.java
index 3bcdb3e9d0..8bf7a0b112 100644
--- a/src/main/java/com/google/devtools/build/lib/buildtool/CqueryBuildTool.java
+++ b/src/main/java/com/google/devtools/build/lib/buildtool/CqueryBuildTool.java
@@ -21,14 +21,16 @@ import com.google.devtools.build.lib.analysis.ViewCreationFailedException;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.config.BuildConfigurationCollection;
 import com.google.devtools.build.lib.events.Event;
-import com.google.devtools.build.lib.query2.CommonQueryOptions;
 import com.google.devtools.build.lib.query2.ConfiguredTargetQueryEnvironment;
+import com.google.devtools.build.lib.query2.TransitionsOutputFormatterCallback;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction;
 import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryException;
 import com.google.devtools.build.lib.query2.engine.QueryExpression;
 import com.google.devtools.build.lib.query2.engine.TargetLiteral;
 import com.google.devtools.build.lib.query2.engine.ThreadSafeOutputFormatterCallback;
+import com.google.devtools.build.lib.query2.output.CqueryOptions;
+import com.google.devtools.build.lib.query2.output.CqueryOptions.Transitions;
 import com.google.devtools.build.lib.runtime.CommandEnvironment;
 import com.google.devtools.build.lib.skyframe.SkyframeExecutorWrappingWalkableGraph;
 import com.google.devtools.build.skyframe.WalkableGraph;
@@ -109,7 +111,6 @@ public class CqueryBuildTool extends BuildTool {
         }
       }
     }
-
     WalkableGraph walkableGraph =
         SkyframeExecutorWrappingWalkableGraph.of(env.getSkyframeExecutor());
     ImmutableList<QueryFunction> extraFunctions =
@@ -117,6 +118,7 @@ public class CqueryBuildTool extends BuildTool {
             .addAll(ConfiguredTargetQueryEnvironment.CQUERY_FUNCTIONS)
             .addAll(env.getRuntime().getQueryFunctions())
             .build();
+    CqueryOptions cqueryOptions = request.getOptions(CqueryOptions.class);
     ConfiguredTargetQueryEnvironment configuredTargetQueryEnvironment =
         new ConfiguredTargetQueryEnvironment(
             request.getKeepGoing(),
@@ -127,11 +129,17 @@ public class CqueryBuildTool extends BuildTool {
             env.newTargetPatternEvaluator().getOffset(),
             env.getPackageManager().getPackagePath(),
             () -> walkableGraph,
-            request.getOptions(CommonQueryOptions.class).toSettings());
-    QueryEvalResult result =
-        configuredTargetQueryEnvironment.evaluateQuery(
-            queryExpression,
-            new ThreadSafeOutputFormatterCallback<ConfiguredTarget>() {
+            cqueryOptions.toSettings());
+    CqueryOptions.Transitions transitions = cqueryOptions.transitions;
+    ThreadSafeOutputFormatterCallback<ConfiguredTarget> callback =
+        !transitions.equals(Transitions.NONE)
+            ? new TransitionsOutputFormatterCallback(
+                configuredTargetQueryEnvironment.getAccessor(),
+                transitions,
+                env.getReporter().getOutErr().getOutputStream(),
+                env.getSkyframeExecutor(),
+                hostConfiguration)
+            : new ThreadSafeOutputFormatterCallback<ConfiguredTarget>() {
               @Override
               public void processOutput(Iterable<ConfiguredTarget> partialResult)
                   throws IOException, InterruptedException {
@@ -147,7 +155,11 @@ public class CqueryBuildTool extends BuildTool {
                   env.getReporter().getOutErr().printOutLn(output.toString());
                 }
               }
-            });
+            };
+    QueryEvalResult result =
+        configuredTargetQueryEnvironment.evaluateQuery(
+            queryExpression,
+            callback);
     if (result.isEmpty()) {
       env.getReporter().handle(Event.info("Empty query results"));
     }
diff --git a/src/main/java/com/google/devtools/build/lib/query2/BUILD b/src/main/java/com/google/devtools/build/lib/query2/BUILD
index 8a0d01f136..2bf456c22a 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/query2/BUILD
@@ -26,6 +26,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib:util",
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/collect/compacthashset",
+        "//src/main/java/com/google/devtools/build/lib/collect/nestedset",
         "//src/main/java/com/google/devtools/build/lib/concurrent",
         "//src/main/java/com/google/devtools/build/lib/graph",
         "//src/main/java/com/google/devtools/build/lib/profiler",
diff --git a/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetAccessor.java b/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetAccessor.java
index cfba199f77..eabd2c6c78 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetAccessor.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetAccessor.java
@@ -106,7 +106,7 @@ class ConfiguredTargetAccessor implements TargetAccessor<ConfiguredTarget> {
     throw new UnsupportedOperationException();
   }
 
-  private Target getTargetFromConfiguredTarget(ConfiguredTarget configuredTarget) {
+  public Target getTargetFromConfiguredTarget(ConfiguredTarget configuredTarget) {
     Target target = null;
     try {
       target =
diff --git a/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetQueryEnvironment.java
index 776a84e28e..547d7d107b 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/ConfiguredTargetQueryEnvironment.java
@@ -148,6 +148,7 @@ public class ConfiguredTargetQueryEnvironment
     this.parserPrefix = parserPrefix;
     this.pkgPath = pkgPath;
     this.walkableGraphSupplier = walkableGraphSupplier;
+    this.accessor = new ConfiguredTargetAccessor(walkableGraphSupplier.get());
   }
 
   private void beforeEvaluateQuery() throws InterruptedException, QueryException {
@@ -160,7 +161,6 @@ public class ConfiguredTargetQueryEnvironment
             eventHandler,
             FilteringPolicies.NO_FILTER,
             MultisetSemaphore.unbounded());
-    accessor = new ConfiguredTargetAccessor(walkableGraphSupplier.get());
     checkSettings(settings);
   }
 
@@ -175,6 +175,10 @@ public class ConfiguredTargetQueryEnvironment
     return ImmutableList.of(new ConfigFunction());
   }
 
+  public BuildConfiguration getHostConfiguration() {
+    return hostConfiguration;
+  }
+
   /**
    * This method has to exist because {@link AliasConfiguredTarget#getLabel()} returns
    * the label of the "actual" target instead of the alias target. Grr.
diff --git a/src/main/java/com/google/devtools/build/lib/query2/TransitionsOutputFormatterCallback.java b/src/main/java/com/google/devtools/build/lib/query2/TransitionsOutputFormatterCallback.java
new file mode 100644
index 0000000000..cd48b94264
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/query2/TransitionsOutputFormatterCallback.java
@@ -0,0 +1,301 @@
+// Copyright 2018 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.query2;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Maps;
+import com.google.devtools.build.lib.analysis.AspectCollection;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.Dependency;
+import com.google.devtools.build.lib.analysis.DependencyResolver;
+import com.google.devtools.build.lib.analysis.DependencyResolver.InconsistentAspectOrderException;
+import com.google.devtools.build.lib.analysis.PlatformSemantics;
+import com.google.devtools.build.lib.analysis.TargetAndConfiguration;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.analysis.config.BuildOptions;
+import com.google.devtools.build.lib.analysis.config.BuildOptions.OptionsDiff;
+import com.google.devtools.build.lib.analysis.config.ConfigMatchingProvider;
+import com.google.devtools.build.lib.analysis.config.FragmentClassSet;
+import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
+import com.google.devtools.build.lib.analysis.config.transitions.ConfigurationTransition;
+import com.google.devtools.build.lib.analysis.config.transitions.NoTransition;
+import com.google.devtools.build.lib.analysis.config.transitions.PatchTransition;
+import com.google.devtools.build.lib.analysis.config.transitions.SplitTransition;
+import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.events.Event;
+import com.google.devtools.build.lib.events.ExtendedEventHandler;
+import com.google.devtools.build.lib.events.NullEventHandler;
+import com.google.devtools.build.lib.packages.Attribute;
+import com.google.devtools.build.lib.packages.BuildType;
+import com.google.devtools.build.lib.packages.ConfiguredAttributeMapper;
+import com.google.devtools.build.lib.packages.NoSuchThingException;
+import com.google.devtools.build.lib.packages.RuleTransitionFactory;
+import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.packages.TargetUtils;
+import com.google.devtools.build.lib.query2.engine.QueryEnvironment.TargetAccessor;
+import com.google.devtools.build.lib.query2.engine.ThreadSafeOutputFormatterCallback;
+import com.google.devtools.build.lib.query2.output.CqueryOptions;
+import com.google.devtools.build.lib.skyframe.SkyframeExecutor;
+import com.google.devtools.build.lib.syntax.EvalException;
+import com.google.devtools.build.lib.util.OrderedSetMultimap;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Output formatter that prints {@link ConfigurationTransition} information for rule configured
+ * targets in the results of a cquery call.
+ */
+public class TransitionsOutputFormatterCallback
+    extends ThreadSafeOutputFormatterCallback<ConfiguredTarget> {
+
+  private final ConfiguredTargetAccessor accessor;
+  private final SkyframeExecutor skyframeExecutor;
+  private final BuildConfiguration hostConfiguration;
+  private final CqueryOptions.Transitions transitions;
+  private final HashMap<Label, Target> partialResultMap;
+
+  private PrintStream printStream = null;
+  private final List<String> result = new ArrayList<>();
+
+  /**
+   * @param accessor provider of query result configured targets.
+   * @param transitions a value of {@link CqueryOptions.Transitions} enum that signals how verbose
+   *     the transition information should be.
+   * @param out output stream. This is nullable for testing purposes since tests directly access
+   *     result.
+   */
+  public TransitionsOutputFormatterCallback(
+      TargetAccessor<ConfiguredTarget> accessor,
+      CqueryOptions.Transitions transitions,
+      OutputStream out,
+      SkyframeExecutor skyframeExecutor,
+      BuildConfiguration hostConfiguration) {
+    this.accessor = (ConfiguredTargetAccessor) accessor;
+    this.skyframeExecutor = skyframeExecutor;
+    this.hostConfiguration = hostConfiguration;
+    Preconditions.checkArgument(
+        !transitions.equals(CqueryOptions.Transitions.NONE),
+        "This formatter callback should never be constructed if "
+            + "CqueryOptions.Transitions == NONE.");
+    this.transitions = transitions;
+    if (out != null) {
+      this.printStream = new PrintStream(out);
+    }
+    this.partialResultMap = Maps.newHashMap();
+  }
+
+  @Override
+  public void processOutput(Iterable<ConfiguredTarget> partialResult)
+      throws IOException, InterruptedException {
+    partialResult.forEach(
+        ct -> partialResultMap.put(ct.getLabel(), accessor.getTargetFromConfiguredTarget(ct)));
+    for (ConfiguredTarget configuredTarget : partialResult) {
+      Target target = partialResultMap.get(configuredTarget.getLabel());
+      BuildConfiguration config = configuredTarget.getConfiguration();
+      addResult(
+          getRuleClassTransition(configuredTarget, target)
+              + configuredTarget.getLabel()
+              + " ("
+              + (config != null && config.isHostConfiguration() ? "HOST" : config)
+              + ")");
+      if (!(configuredTarget instanceof RuleConfiguredTarget)) {
+        continue;
+      }
+      OrderedSetMultimap<Attribute, Dependency> deps;
+      ImmutableMap<Label, ConfigMatchingProvider> configConditions =
+          ((RuleConfiguredTarget) configuredTarget).getConfigConditions();
+      BuildOptions fromOptions = config.getOptions();
+      try {
+        // Note: Being able to pull the $toolchain attr unconditionally from the mapper relies on
+        // the fact that {@link PlatformSemantics.TOOLCHAIN_ATTRS} exists in every rule.
+        // Also, we don't actually use fromOptions in our implementation of DependencyResolver but
+        // passing to avoid passing a null and since we have the information anyway.
+        deps =
+            new FormatterDependencyResolver(configuredTarget, NullEventHandler.INSTANCE)
+                .dependentNodeMap(
+                    new TargetAndConfiguration(target, config),
+                    hostConfiguration,
+                    /*aspect=*/ null,
+                    configConditions,
+                    ImmutableSet.copyOf(
+                        ConfiguredAttributeMapper.of(target.getAssociatedRule(), configConditions)
+                            .get(PlatformSemantics.TOOLCHAINS_ATTR, BuildType.LABEL_LIST)),
+                    fromOptions);
+      } catch (EvalException | InvalidConfigurationException | InconsistentAspectOrderException e) {
+        throw new InterruptedException(e.getMessage());
+      }
+      for (Map.Entry<Attribute, Dependency> attributeAndDep : deps.entries()) {
+        if (attributeAndDep.getValue().hasExplicitConfiguration()
+            || attributeAndDep.getValue().getTransition() instanceof NoTransition) {
+          continue;
+        }
+        List<BuildOptions> toOptions;
+        Dependency dep = attributeAndDep.getValue();
+        ConfigurationTransition transition = dep.getTransition();
+        if (transition instanceof SplitTransition) {
+          toOptions = ((SplitTransition) transition).split(fromOptions);
+        } else if (transition instanceof PatchTransition) {
+          toOptions = Collections.singletonList(((PatchTransition) transition).apply(fromOptions));
+        } else {
+          throw new IllegalStateException(
+              "If this error is thrown, cquery needs to be updated to take into account non-Patch"
+                  + " and non-Split Transitions");
+        }
+        String hostConfigurationChecksum = hostConfiguration.checksum();
+        addResult(
+            "  "
+                .concat(attributeAndDep.getKey().getName())
+                .concat("#")
+                .concat(dep.getLabel().toString())
+                .concat("#")
+                .concat(dep.getTransition().getName())
+                .concat(" ( -> ")
+                .concat(
+                    toOptions
+                        .stream()
+                        .map(options -> {
+                          String checksum = BuildConfiguration.computeChecksum(options);
+                          return checksum.equals(hostConfigurationChecksum) ? "HOST" : checksum;
+                        })
+                        .collect(Collectors.joining(", ")))
+                .concat(")"));
+        if (transitions == CqueryOptions.Transitions.LITE) {
+          continue;
+        }
+        OptionsDiff diff = new OptionsDiff();
+        for (BuildOptions options : toOptions) {
+          diff = BuildOptions.diff(diff, fromOptions, options);
+        }
+        diff.getPrettyPrintList().forEach(singleDiff -> addResult("    " + singleDiff));
+      }
+    }
+  }
+
+  private String getRuleClassTransition(ConfiguredTarget ct, Target target) {
+    String output = "";
+    if (ct instanceof RuleConfiguredTarget) {
+      RuleTransitionFactory factory =
+          target.getAssociatedRule().getRuleClassObject().getTransitionFactory();
+      if (factory != null) {
+        output =
+            factory
+                .buildTransitionFor(target.getAssociatedRule())
+                .getClass()
+                .getSimpleName()
+                .concat(" -> ");
+      }
+    }
+    return output;
+  }
+
+  private void addResult(String string) {
+    result.add(string);
+  }
+
+  @VisibleForTesting
+  public List<String> getResult() {
+    return result;
+  }
+
+  @Override
+  public void close(boolean failFast) throws InterruptedException, IOException {
+    if (!failFast && printStream != null) {
+      result.forEach(printStream::println);
+    }
+  }
+
+  private class FormatterDependencyResolver extends DependencyResolver {
+
+    private ConfiguredTarget ct;
+    private final ExtendedEventHandler eventHandler;
+
+    private FormatterDependencyResolver(ConfiguredTarget ct, ExtendedEventHandler eventHandler) {
+      this.ct = ct;
+      this.eventHandler = eventHandler;
+    }
+
+    protected FormatterDependencyResolver setCt(ConfiguredTarget ct) {
+      this.ct = ct;
+      return this;
+    }
+
+    @Override
+    protected void invalidVisibilityReferenceHook(TargetAndConfiguration node, Label label) {
+      eventHandler.handle(
+          Event.error(
+              TargetUtils.getLocationMaybe(node.getTarget()),
+              String.format(
+                  "Label '%s' in visibility attribute does not refer to a package group", label)));
+    }
+
+    @Override
+    protected void invalidPackageGroupReferenceHook(TargetAndConfiguration node, Label label) {
+      eventHandler.handle(
+          Event.error(
+              TargetUtils.getLocationMaybe(node.getTarget()),
+              String.format("label '%s' does not refer to a package group", label)));
+    }
+
+    @Override
+    protected void missingEdgeHook(Target from, Label to, NoSuchThingException e) {
+      eventHandler.handle(
+          Event.error(
+              "missing dependency from " + from.getLabel() + " to " + to + ": " + e.getMessage()));
+    }
+
+    @Override
+    protected Target getTarget(Target from, Label label, NestedSetBuilder<Label> rootCauses)
+        throws InterruptedException {
+      return partialResultMap.get(label);
+    }
+
+    @Override
+    protected List<BuildConfiguration> getConfigurations(
+        FragmentClassSet fragments,
+        Iterable<BuildOptions> buildOptions,
+        BuildOptions defaultOptions) {
+      Preconditions.checkArgument(
+          ct.getConfiguration().fragmentClasses().equals(fragments),
+          "Mismatch: %s %s",
+          ct,
+          fragments);
+      Dependency asDep =
+          Dependency.withTransitionAndAspects(
+              ct.getLabel(), NoTransition.INSTANCE, AspectCollection.EMPTY);
+      ImmutableList.Builder<BuildConfiguration> builder = ImmutableList.builder();
+      for (BuildOptions options : buildOptions) {
+        builder.add(
+            Iterables.getOnlyElement(
+                skyframeExecutor
+                    .getConfigurations(eventHandler, options, ImmutableList.<Dependency>of(asDep))
+                    .values()));
+      }
+      return builder.build();
+    }
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/QueryParser.java b/src/main/java/com/google/devtools/build/lib/query2/engine/QueryParser.java
index 8d35aedcfa..64dd0e6d95 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/engine/QueryParser.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/engine/QueryParser.java
@@ -55,7 +55,7 @@ public final class QueryParser {
   /**
    * Scan and parse the specified query expression.
    */
-  static QueryExpression parse(String query, QueryEnvironment<?> env) throws QueryException {
+  public static QueryExpression parse(String query, QueryEnvironment<?> env) throws QueryException {
     HashMap<String, QueryFunction> functions = new HashMap<>();
     for (QueryFunction queryFunction : env.getFunctions()) {
       functions.put(queryFunction.getName(), queryFunction);
diff --git a/src/main/java/com/google/devtools/build/lib/query2/output/CqueryOptions.java b/src/main/java/com/google/devtools/build/lib/query2/output/CqueryOptions.java
new file mode 100644
index 0000000000..9d9cb0d099
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/query2/output/CqueryOptions.java
@@ -0,0 +1,49 @@
+// Copyright 2018 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.query2.output;
+
+import com.google.devtools.build.lib.query2.CommonQueryOptions;
+import com.google.devtools.common.options.EnumConverter;
+import com.google.devtools.common.options.Option;
+import com.google.devtools.common.options.OptionDocumentationCategory;
+import com.google.devtools.common.options.OptionEffectTag;
+
+/** Options class for cquery specific query options. */
+public class CqueryOptions extends CommonQueryOptions {
+
+  /** Converter for {@link CqueryOptions.Transitions} enum. */
+  public static class TransitionsConverter extends EnumConverter<Transitions> {
+    public TransitionsConverter() {
+      super(Transitions.class, "transition verbosity");
+    }
+  }
+
+  /** How much information to output about transitions. */
+  public enum Transitions {
+    FULL, /** includes everything in LITE plus transition's effect on options. */
+    LITE, /** includes which attribute the transition is applied on and class name of transition */
+    NONE /** default value, no transition information */
+  }
+
+  @Option(
+      name = "transitions",
+      converter = TransitionsConverter.class,
+      defaultValue = "none",
+      documentationCategory = OptionDocumentationCategory.QUERY,
+      effectTags = {OptionEffectTag.AFFECTS_OUTPUTS},
+      help = "The format in which cquery will print transition information."
+  )
+  public Transitions transitions;
+
+}
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/commands/CqueryCommand.java b/src/main/java/com/google/devtools/build/lib/runtime/commands/CqueryCommand.java
index 6a80e0849e..acd9f0d9d1 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/commands/CqueryCommand.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/commands/CqueryCommand.java
@@ -18,12 +18,12 @@ import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.buildtool.BuildRequest;
 import com.google.devtools.build.lib.buildtool.CqueryBuildTool;
 import com.google.devtools.build.lib.events.Event;
-import com.google.devtools.build.lib.query2.CommonQueryOptions;
 import com.google.devtools.build.lib.query2.ConfiguredTargetQueryEnvironment;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction;
 import com.google.devtools.build.lib.query2.engine.QueryException;
 import com.google.devtools.build.lib.query2.engine.QueryExpression;
 import com.google.devtools.build.lib.query2.engine.QueryParser;
+import com.google.devtools.build.lib.query2.output.CqueryOptions;
 import com.google.devtools.build.lib.runtime.BlazeCommand;
 import com.google.devtools.build.lib.runtime.BlazeCommandResult;
 import com.google.devtools.build.lib.runtime.BlazeRuntime;
@@ -45,7 +45,7 @@ import java.util.Set;
   name = "cquery",
   builds = true,
   inherits = {BuildCommand.class},
-  options = {CommonQueryOptions.class},
+  options = {CqueryOptions.class},
   usesConfigurationOptions = true,
   shortDescription = "Loads, analyzes, and queries the specified targets w/ configurations.",
   allowResidue = true,
@@ -92,7 +92,7 @@ public final class CqueryCommand implements BlazeCommand {
       return BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR);
     }
 
-    List<String> topLevelTargets = options.getOptions(CommonQueryOptions.class).universeScope;
+    List<String> topLevelTargets = options.getOptions(CqueryOptions.class).universeScope;
     Set<String> targetPatternSet = new LinkedHashSet<>();
     if (topLevelTargets.isEmpty()) {
       expr.collectTargetPatterns(targetPatternSet);