Add a method for getting the root of a rule workspace to the Label method

This method is exposed to Skylark and will enable correct handling of protobuf skylark files.
See #784

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MOS_MIGRATED_REVID=112235357

1 files changed, 8 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/cmdline/LabelTest.java b/src/test/java/com/google/devtools/build/lib/cmdline/LabelTest.java
index ec10104895..1f3ce8b212 100644
--- a/src/test/java/com/google/devtools/build/lib/cmdline/LabelTest.java
+++ b/src/test/java/com/google/devtools/build/lib/cmdline/LabelTest.java
@@ -353,4 +353,12 @@ public class LabelTest {
           "invalid repository name 'foo': workspace names must start with '@'");
     }
   }
+  
+  @Test
+  public void testGetWorkspaceRoot() throws Exception {
+    Label label = Label.parseAbsolute("//bar/baz");
+    assertThat(label.getWorkspaceRoot()).isEmpty();
+    label = Label.parseAbsolute("@repo//bar/baz");
+    assertThat(label.getWorkspaceRoot()).isEqualTo("external/repo");
+  }
 }