Make the execution root match the runfiles tree structure for external repositories

One interesting side effect of how this is implemented is that for external
repositories, bin/ and genfiles/ are combined.  External repo output is under
bazel-out/local-fastbuild/repo_name for each repo.

Fixes #1262.

RELNOTES[INC]: Previously, an external repository would be symlinked into the
execution root at execroot/local_repo/external/remote_repo. This changes it to
be at execroot/remote_repo. This may break genrules/Skylark actions that
hardcode execution root paths. If this causes breakages for you, ensure that
genrules are using $(location :target) to access files and Skylark rules are
using http://bazel.io/docs/skylark/lib/File.html's path, dirname, etc.
functions.

--
MOS_MIGRATED_REVID=125095799

2 files changed, 16 insertions, 16 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/actions/ArtifactFactoryTest.java b/src/test/java/com/google/devtools/build/lib/actions/ArtifactFactoryTest.java
index f9c31ca044..317051b9d4 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/ArtifactFactoryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/ArtifactFactoryTest.java
@@ -150,25 +150,26 @@ public class ArtifactFactoryTest {
   }
 
   @Test
-  public void testResolveArtifactWithUpLevelFailsCleanly() throws Exception {
+  public void testResolveArtifactWithUpLevel() throws Exception {
     // We need a package in the root directory to make every exec path (even one with up-level
     // references) be in a package.
     Map<PackageIdentifier, Root> packageRoots = ImmutableMap.of(
-        PackageIdentifier.createInMainRepo(new PathFragment("")), clientRoot);
+        PackageIdentifier.create("@workspace", new PathFragment("")), clientRoot,
+        PackageIdentifier.create("@repo", new PathFragment("dir")), clientRoot);
     artifactFactory.setPackageRoots(packageRoots);
-    PathFragment outsideWorkspace = new PathFragment("../foo");
-    PathFragment insideWorkspace =
-        new PathFragment("../" + clientRoot.getPath().getBaseName() + "/foo");
-    assertNull(artifactFactory.resolveSourceArtifact(outsideWorkspace));
-    assertNull("Up-level-containing paths that descend into the right workspace aren't allowed",
-            artifactFactory.resolveSourceArtifact(insideWorkspace));
+    PathFragment topLevel = new PathFragment("../workspace/foo");
+    PathFragment subdir = new PathFragment("../repo/dir/foo");
+    Artifact topLevelArtifact = artifactFactory.resolveSourceArtifact(topLevel);
+    assertThat(topLevelArtifact).isNotNull();
+    Artifact subdirArtifact = artifactFactory.resolveSourceArtifact(subdir);
+    assertThat(subdirArtifact).isNotNull();
     MockPackageRootResolver packageRootResolver = new MockPackageRootResolver();
     packageRootResolver.setPackageRoots(packageRoots);
     Map<PathFragment, Artifact> result = new HashMap<>();
-    result.put(insideWorkspace, null);
-    result.put(outsideWorkspace, null);
+    result.put(topLevel, topLevelArtifact);
+    result.put(subdir, subdirArtifact);
     assertThat(
-        artifactFactory.resolveSourceArtifacts(ImmutableList.of(insideWorkspace, outsideWorkspace),
+        artifactFactory.resolveSourceArtifacts(ImmutableList.of(topLevel, subdir),
             packageRootResolver).entrySet()).containsExactlyElementsIn(result.entrySet());
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/actions/ArtifactTest.java b/src/test/java/com/google/devtools/build/lib/actions/ArtifactTest.java
index e43ddd1b28..676eab402a 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/ArtifactTest.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/ArtifactTest.java
@@ -57,13 +57,12 @@ public class ArtifactTest {
   }
 
   @Test
-  public void testConstruction_badRootDir() throws IOException {
+  public void testConstruction_UplevelRootDir() throws IOException {
     Path f1 = scratch.file("/exec/dir/file.ext");
     Path bogusDir = scratch.file("/exec/dir/bogus");
-    try {
-      new Artifact(f1, Root.asDerivedRoot(bogusDir), f1.relativeTo(execDir));
-      fail("Expected IllegalArgumentException constructing artifact with a bad root dir");
-    } catch (IllegalArgumentException expected) {}
+    Artifact artifact = new Artifact(f1, Root.asDerivedRoot(bogusDir), f1.relativeTo(execDir));
+    assertThat(artifact.getExecPath()).isEqualTo(new PathFragment("dir/file.ext"));
+    assertThat(artifact.getRootRelativePath()).isEqualTo(new PathFragment("../file.ext"));
   }
 
   @Test