Decanonicalize labels emitted by {a,c,}query if possible

Uses the newly added `PackageIdentifier#getDisplayForm` to turn labels
in the output of query, aquery, and cquery into the most concise
representation that allows them to be resolved from the context of the
main repository.

src/main/java/com/google/devtools/build/lib/cmdline/Label.java

@@ -416,9 +416,21 @@ public String getCanonicalForm() {
    * Label.parse*(x.getUnambiguousCanonicalForm(), ...).equals(x)}).
    */
   public String getUnambiguousCanonicalForm() {
-    return String.format(
-        "@@%s//%s:%s",
-        packageIdentifier.getRepository().getName(), packageIdentifier.getPackageFragment(), name);
+    return packageIdentifier.getUnambiguousCanonicalForm() + ":" + name;
+  }
+
+  /**
+   * Returns a label string that is suitable for display, i.e., it resolves to this label when
+   * parsed in the context of the main repository and has a repository part that is as simple as
+   * possible.
+   *
+   * @param mainOrOtherRepoMapping the {@link RepositoryMapping} of the main repository or, if that
+   *                               is not available to the caller, the {@link RepositoryMapping} of
+   *                               the current package. The former will yield more readable output.
+   * @return analogous to {@link PackageIdentifier#getDisplayForm(RepositoryMapping)}
+   */
+  public String getDisplayForm(RepositoryMapping mainOrOtherRepoMapping) {
+    return packageIdentifier.getDisplayForm(mainOrOtherRepoMapping) + ":" + name;
   }
 
   /** Return the name of the repository label refers to without the leading `at` symbol. */

src/main/java/com/google/devtools/build/lib/cmdline/TargetPattern.java

@@ -39,6 +39,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.regex.Pattern;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;

src/main/java/com/google/devtools/build/lib/query2/PostAnalysisQueryEnvironment.java

@@ -28,6 +28,7 @@
 import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
 import com.google.devtools.build.lib.cmdline.TargetPattern;
 import com.google.devtools.build.lib.collect.compacthashset.CompactHashSet;
@@ -251,6 +252,11 @@ protected TargetPattern getPattern(String pattern) throws TargetParsingException
     return mainRepoTargetParser.parse(pattern);
   }
 
+  @Override
+  public RepositoryMapping getMainRepoMapping() {
+    return mainRepoTargetParser.getRepoMapping();
+  }
+
   public ThreadSafeMutableSet<T> getFwdDeps(Iterable<T> targets) throws InterruptedException {
     Map<SkyKey, T> targetsByKey = Maps.newHashMapWithExpectedSize(Iterables.size(targets));
     for (T target : targets) {

src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java

@@ -42,6 +42,7 @@
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.ParallelVisitor.VisitTaskStatusCallback;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.cmdline.SignedTargetPattern;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
 import com.google.devtools.build.lib.cmdline.TargetPattern;
@@ -958,6 +959,12 @@ public TargetAccessor<Target> getAccessor() {
     return accessor;
   }
 
+  @Override
+  @ThreadSafe
+  public RepositoryMapping getMainRepoMapping() {
+    return mainRepoTargetParser.getRepoMapping();
+  }
+
   @ThreadSafe
   private Package getPackage(PackageIdentifier packageIdentifier)
       throws InterruptedException, QueryException, NoSuchPackageException {

src/main/java/com/google/devtools/build/lib/query2/aquery/ActionGraphQueryEnvironment.java

@@ -170,7 +170,8 @@ public ConfiguredTargetValueAccessor getAccessor() {
             StreamedOutputHandler.OutputType.JSON,
             actionFilters),
         new ActionGraphTextOutputFormatterCallback(
-            eventHandler, aqueryOptions, out, skyframeExecutor, accessor, actionFilters),
+            eventHandler, aqueryOptions, out, skyframeExecutor, accessor, actionFilters,
+            getMainRepoMapping()),
         new ActionGraphSummaryOutputFormatterCallback(
             eventHandler, aqueryOptions, out, skyframeExecutor, accessor, actionFilters));
   }

src/main/java/com/google/devtools/build/lib/query2/aquery/ActionGraphTextOutputFormatterCallback.java

@@ -38,6 +38,7 @@
 import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction;
 import com.google.devtools.build.lib.buildeventstream.BuildEvent;
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.events.ExtendedEventHandler;
 import com.google.devtools.build.lib.packages.AspectDescriptor;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.TargetAccessor;
@@ -62,6 +63,7 @@ class ActionGraphTextOutputFormatterCallback extends AqueryThreadsafeCallback {
 
   private final ActionKeyContext actionKeyContext = new ActionKeyContext();
   private final AqueryActionFilter actionFilters;
+  private final RepositoryMapping mainRepoMapping;
   private Map<String, String> paramFileNameToContentMap;
 
   ActionGraphTextOutputFormatterCallback(
@@ -70,9 +72,11 @@ class ActionGraphTextOutputFormatterCallback extends AqueryThreadsafeCallback {
       OutputStream out,
       SkyframeExecutor skyframeExecutor,
       TargetAccessor<KeyedConfiguredTargetValue> accessor,
-      AqueryActionFilter actionFilters) {
+      AqueryActionFilter actionFilters,
+      RepositoryMapping mainRepoMapping) {
     super(eventHandler, options, out, skyframeExecutor, accessor);
     this.actionFilters = actionFilters;
+    this.mainRepoMapping = mainRepoMapping;
   }
 
   @Override
@@ -145,15 +149,15 @@ private void writeAction(ActionAnalysisMetadata action, PrintStream printStream)
 
       stringBuilder
           .append("  Target: ")
-          .append(actionOwner.getLabel())
+          .append(actionOwner.getLabel().getDisplayForm(mainRepoMapping))
           .append('\n')
           .append("  Configuration: ")
           .append(configProto.getMnemonic())
           .append('\n');
       if (actionOwner.getExecutionPlatform() != null) {
         stringBuilder
             .append("  Execution platform: ")
-            .append(actionOwner.getExecutionPlatform().label().toString())
+            .append(actionOwner.getExecutionPlatform().label().getDisplayForm(mainRepoMapping))
             .append("\n");
       }
 

src/main/java/com/google/devtools/build/lib/query2/cquery/ConfiguredTargetQueryEnvironment.java

@@ -30,6 +30,7 @@
 import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
 import com.google.devtools.build.lib.cmdline.TargetPattern;
 import com.google.devtools.build.lib.events.ExtendedEventHandler;
@@ -205,17 +206,20 @@ private static ImmutableMap<String, BuildConfigurationValue> getTransitiveConfig
         cqueryOptions.aspectDeps.createResolver(packageManager, eventHandler);
     return ImmutableList.of(
         new LabelAndConfigurationOutputFormatterCallback(
-            eventHandler, cqueryOptions, out, skyframeExecutor, accessor, true),
+            eventHandler, cqueryOptions, out, skyframeExecutor, accessor, true,
+            getMainRepoMapping()),
         new LabelAndConfigurationOutputFormatterCallback(
-            eventHandler, cqueryOptions, out, skyframeExecutor, accessor, false),
+            eventHandler, cqueryOptions, out, skyframeExecutor, accessor, false,
+            getMainRepoMapping()),
         new TransitionsOutputFormatterCallback(
             eventHandler,
             cqueryOptions,
             out,
             skyframeExecutor,
             accessor,
             hostConfiguration,
-            trimmingTransitionFactory),
+            trimmingTransitionFactory,
+            getMainRepoMapping()),
         new ProtoOutputFormatterCallback(
             eventHandler,
             cqueryOptions,

src/main/java/com/google/devtools/build/lib/query2/cquery/LabelAndConfigurationOutputFormatterCallback.java

@@ -18,6 +18,7 @@
 import com.google.devtools.build.lib.analysis.RequiredConfigFragmentsProvider;
 import com.google.devtools.build.lib.analysis.config.CoreOptions.IncludeConfigFragmentsEnum;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.events.ExtendedEventHandler;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.TargetAccessor;
@@ -28,16 +29,19 @@
 /** Default Output callback for cquery. Prints a label and configuration pair per result. */
 public class LabelAndConfigurationOutputFormatterCallback extends CqueryThreadsafeCallback {
   private final boolean showKind;
+  private final RepositoryMapping mainRepoMapping;
 
   LabelAndConfigurationOutputFormatterCallback(
       ExtendedEventHandler eventHandler,
       CqueryOptions options,
       OutputStream out,
       SkyframeExecutor skyframeExecutor,
       TargetAccessor<KeyedConfiguredTarget> accessor,
-      boolean showKind) {
+      boolean showKind,
+      RepositoryMapping mainRepoMapping) {
     super(eventHandler, options, out, skyframeExecutor, accessor, /*uniquifyResults=*/ false);
     this.showKind = showKind;
+    this.mainRepoMapping = mainRepoMapping;
   }
 
   @Override
@@ -55,7 +59,7 @@ public void processOutput(Iterable<KeyedConfiguredTarget> partialResult) {
       }
       output =
           output
-              .append(keyedConfiguredTarget.getLabel())
+              .append(keyedConfiguredTarget.getLabel().getDisplayForm(mainRepoMapping))
               .append(" (")
               .append(shortId(getConfiguration(keyedConfiguredTarget.getConfigurationKey())))
               .append(")");

src/main/java/com/google/devtools/build/lib/query2/cquery/TransitionsOutputFormatterCallback.java

@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.ExtendedEventHandler;
 import com.google.devtools.build.lib.packages.RuleTransitionData;
@@ -47,7 +48,9 @@ class TransitionsOutputFormatterCallback extends CqueryThreadsafeCallback {
   protected final BuildConfigurationValue hostConfiguration;
 
   private final HashMap<Label, Target> partialResultMap;
-  @Nullable private final TransitionFactory<RuleTransitionData> trimmingTransitionFactory;
+  @Nullable
+  private final TransitionFactory<RuleTransitionData> trimmingTransitionFactory;
+  private final RepositoryMapping mainRepoMapping;
 
   @Override
   public String getName() {
@@ -65,11 +68,13 @@ public String getName() {
       SkyframeExecutor skyframeExecutor,
       TargetAccessor<KeyedConfiguredTarget> accessor,
       BuildConfigurationValue hostConfiguration,
-      @Nullable TransitionFactory<RuleTransitionData> trimmingTransitionFactory) {
+      @Nullable TransitionFactory<RuleTransitionData> trimmingTransitionFactory,
+      RepositoryMapping mainRepoMapping) {
     super(eventHandler, options, out, skyframeExecutor, accessor, /*uniquifyResults=*/ false);
     this.hostConfiguration = hostConfiguration;
     this.trimmingTransitionFactory = trimmingTransitionFactory;
     this.partialResultMap = Maps.newHashMap();
+    this.mainRepoMapping = mainRepoMapping;
   }
 
   @Override
@@ -91,8 +96,9 @@ public void processOutput(Iterable<KeyedConfiguredTarget> partialResult)
       addResult(
           getRuleClassTransition(keyedConfiguredTarget.getConfiguredTarget(), target)
               + String.format(
-                  "%s (%s)",
-                  keyedConfiguredTarget.getConfiguredTarget().getOriginalLabel(), shortId(config)));
+              "%s (%s)",
+              keyedConfiguredTarget.getConfiguredTarget().getOriginalLabel()
+                  .getDisplayForm(mainRepoMapping), shortId(config)));
       KnownTargetsDependencyResolver knownTargetsDependencyResolver =
           new KnownTargetsDependencyResolver(partialResultMap);
       ImmutableSet<ResolvedTransition> dependencies;
@@ -117,7 +123,7 @@ public void processOutput(Iterable<KeyedConfiguredTarget> partialResult)
             "  "
                 .concat(dep.attributeName())
                 .concat("#")
-                .concat(dep.label().toString())
+                .concat(dep.label().getDisplayForm(mainRepoMapping))
                 .concat("#")
                 .concat(dep.transitionName())
                 .concat(" -> ")

src/main/java/com/google/devtools/build/lib/query2/engine/QueryEnvironment.java

@@ -19,6 +19,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.util.DetailedExitCode;
@@ -536,6 +537,10 @@ ThreadSafeMutableSet<T> getBuildFiles(
    */
   TargetAccessor<T> getAccessor();
 
+  default RepositoryMapping getMainRepoMapping() {
+    return RepositoryMapping.ALWAYS_FALLBACK;
+  }
+
   /**
    * Whether the given setting is enabled. The code should default to return {@code false} for all
    * unknown settings. The enum is used rather than a method for each setting so that adding more

src/main/java/com/google/devtools/build/lib/query2/query/BlazeQueryEnvironment.java

@@ -20,6 +20,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
 import com.google.devtools.build.lib.cmdline.TargetPattern;
 import com.google.devtools.build.lib.cmdline.TargetPattern.Parser;
@@ -500,6 +501,11 @@ public TargetAccessor<Target> getAccessor() {
     return accessor;
   }
 
+  @Override
+  public RepositoryMapping getMainRepoMapping() {
+    return mainRepoTargetParser.getRepoMapping();
+  }
+
   /** Given a set of target nodes, returns the targets. */
   private ThreadSafeMutableSet<Target> getTargetsFromNodes(Iterable<Node<Target>> input) {
     ThreadSafeMutableSet<Target> result = createThreadSafeMutableSet();

src/main/java/com/google/devtools/build/lib/query2/query/GraphlessBlazeQueryEnvironment.java

@@ -17,6 +17,7 @@
 import com.google.common.collect.Sets;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
 import com.google.devtools.build.lib.cmdline.TargetPattern;
 import com.google.devtools.build.lib.cmdline.TargetPattern.Parser;
@@ -507,4 +508,9 @@ protected void preloadOrThrow(QueryExpression caller, Collection<String> pattern
   public TargetAccessor<Target> getAccessor() {
     return accessor;
   }
+
+  @Override
+  public RepositoryMapping getMainRepoMapping() {
+    return mainRepoTargetParser.getRepoMapping();
+  }
 }

src/main/java/com/google/devtools/build/lib/query2/query/output/AbstractUnorderedFormatter.java

@@ -22,6 +22,7 @@
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.query2.common.CommonQueryOptions;
 import com.google.devtools.build.lib.query2.engine.OutputFormatterCallback;
+import com.google.devtools.build.lib.query2.engine.QueryEnvironment;
 import com.google.devtools.build.lib.query2.query.aspectresolvers.AspectResolver;
 import com.google.devtools.build.lib.query2.query.output.QueryOptions.OrderOutput;
 import java.io.IOException;
@@ -40,6 +41,7 @@ public void setEventHandler(@Nullable EventHandler eventHandler) {}
 
   @Override
   public void output(
+      QueryEnvironment<?> env,
       QueryOptions options,
       Digraph<Target> result,
       OutputStream out,
@@ -50,7 +52,7 @@ public void output(
     setOptions(options, aspectResolver, hashFunction);
     setEventHandler(eventHandler);
     OutputFormatterCallback.processAllTargets(
-        createPostFactoStreamCallback(out, options), getOrderedTargets(result, options));
+        createPostFactoStreamCallback(out, options, env), getOrderedTargets(result, options));
   }
 
   protected Iterable<Target> getOrderedTargets(Digraph<Target> result, QueryOptions options) {

src/main/java/com/google/devtools/build/lib/query2/query/output/BuildOutputFormatter.java

@@ -221,15 +221,15 @@ private String reconstructSelect(Rule rule, Attribute attr) {
   /** Query's implementation. */
   @Override
   public OutputFormatterCallback<Target> createPostFactoStreamCallback(
-      OutputStream out, final QueryOptions options) {
+      OutputStream out, final QueryOptions options, QueryEnvironment<?> env) {
     return new BuildOutputFormatterCallback(out, options.getLineTerminator());
   }
 
   @Override
   public ThreadSafeOutputFormatterCallback<Target> createStreamCallback(
       OutputStream out, QueryOptions options, QueryEnvironment<?> env) {
     return new SynchronizedDelegatingOutputFormatterCallback<>(
-        createPostFactoStreamCallback(out, options));
+        createPostFactoStreamCallback(out, options, env));
   }
 
   private static class BuildOutputFormatterCallback extends TextOutputFormatterCallback<Target> {

src/main/java/com/google/devtools/build/lib/query2/query/output/GraphOutputFormatter.java

@@ -18,6 +18,7 @@
 import com.google.devtools.build.lib.graph.Digraph;
 import com.google.devtools.build.lib.graph.Node;
 import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.query2.engine.QueryEnvironment;
 import com.google.devtools.build.lib.query2.query.aspectresolvers.AspectResolver;
 import com.google.devtools.build.lib.query2.query.output.FormatUtils.TargetOrdering;
 import com.google.devtools.build.lib.query2.query.output.GraphOutputWriter.NodeReader;
@@ -53,6 +54,7 @@ public Comparator<Target> comparator() {
 
   @Override
   public void output(
+      QueryEnvironment<?> env,
       QueryOptions options,
       Digraph<Target> result,
       OutputStream out,

src/main/java/com/google/devtools/build/lib/query2/query/output/LabelOutputFormatter.java

@@ -42,7 +42,7 @@ public String getName() {
 
   @Override
   public OutputFormatterCallback<Target> createPostFactoStreamCallback(
-      OutputStream out, final QueryOptions options) {
+      OutputStream out, final QueryOptions options, QueryEnvironment<?> env) {
     return new TextOutputFormatterCallback<Target>(out) {
       @Override
       public void processOutput(Iterable<Target> partialResult) throws IOException {
@@ -53,7 +53,7 @@ public void processOutput(Iterable<Target> partialResult) throws IOException {
             writer.append(' ');
           }
           Label label = target.getLabel();
-          writer.append(label.getCanonicalForm()).append(lineTerm);
+          writer.append(label.getDisplayForm(env.getMainRepoMapping())).append(lineTerm);
         }
       }
     };
@@ -63,6 +63,6 @@ public void processOutput(Iterable<Target> partialResult) throws IOException {
   public ThreadSafeOutputFormatterCallback<Target> createStreamCallback(
       OutputStream out, QueryOptions options, QueryEnvironment<?> env) {
     return new SynchronizedDelegatingOutputFormatterCallback<>(
-        createPostFactoStreamCallback(out, options));
+        createPostFactoStreamCallback(out, options, env));
   }
 }