1 files changed, 86 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTargetCycleReporter.java b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTargetCycleReporter.java
new file mode 100644
index 0000000000..03bbd25259
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/TransitiveTargetCycleReporter.java
@@ -0,0 +1,86 @@
+// Copyright 2014 Google Inc. 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.skyframe;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+import com.google.devtools.build.lib.packages.PackageGroup;
+import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.pkgcache.LoadedPackageProvider;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.skyframe.CycleInfo;
+import com.google.devtools.build.skyframe.SkyKey;
+
+import java.util.List;
+
+/**
+ * Reports cycles between {@link TransitiveTargetValue}s. These indicates cycles between targets
+ * (e.g. '//a:foo' depends on '//b:bar' and '//b:bar' depends on '//a:foo').
+ */
+class TransitiveTargetCycleReporter extends AbstractLabelCycleReporter {
+
+  private static final Predicate<SkyKey> IS_TRANSITIVE_TARGET_SKY_KEY =
+      SkyFunctions.isSkyFunction(SkyFunctions.TRANSITIVE_TARGET);
+
+  TransitiveTargetCycleReporter(LoadedPackageProvider loadedPackageProvider) {
+    super(loadedPackageProvider);
+  }
+
+  @Override
+  protected boolean canReportCycle(SkyKey topLevelKey, CycleInfo cycleInfo) {
+    return Iterables.all(Iterables.concat(ImmutableList.of(topLevelKey),
+        cycleInfo.getPathToCycle(), cycleInfo.getCycle()),
+        IS_TRANSITIVE_TARGET_SKY_KEY);
+  }
+
+  @Override
+  public String prettyPrint(SkyKey key) {
+    return getLabel(key).toString();
+  }
+
+  @Override
+  protected Label getLabel(SkyKey key) {
+    return (Label) key.argument();
+  }
+
+  @Override
+  protected String getAdditionalMessageAboutCycle(SkyKey topLevelKey, CycleInfo cycleInfo) {
+    Target currentTarget = getTargetForLabel(getLabel(topLevelKey));
+    List<SkyKey> keys = Lists.newArrayList();
+    if (!cycleInfo.getPathToCycle().isEmpty()) {
+      keys.add(topLevelKey);
+      keys.addAll(cycleInfo.getPathToCycle());
+    }
+    keys.addAll(cycleInfo.getCycle());
+    // Make sure we check the edge from the last element of the cycle to the first element of the
+    // cycle.
+    keys.add(cycleInfo.getCycle().get(0));
+    for (SkyKey nextKey : keys) {
+      Label nextLabel = getLabel(nextKey);
+      Target nextTarget = getTargetForLabel(nextLabel);
+      // This is inefficient but it's no big deal since we only do this when there's a cycle.
+      if (currentTarget.getVisibility().getDependencyLabels().contains(nextLabel)
+          && !nextTarget.getTargetKind().equals(PackageGroup.targetKind())) {
+        return "\nThe cycle is caused by a visibility edge from " + currentTarget.getLabel()
+            + " to the non-package-group target " + nextTarget.getLabel() + " . Note that "
+            + "visibility labels are supposed to be package group targets (which prevents cycles "
+            + "of this form)";
+      }
+      currentTarget = nextTarget;
+    }
+    return "";
+  }
+}