Include tip in hg result set

Helps with golang/dep#170

vcs_source.go

@@ -405,20 +405,22 @@ func (s *hgSource) listVersions(ctx context.Context) ([]PairedVersion, error) {
 			continue
 		}
 
-		// tip is magic, don't include it
-		if bytes.HasPrefix(line, []byte("tip")) {
-			continue
-		}
-
 		// Split on colon; this gets us the rev and the tag plus local revno
 		pair := bytes.Split(line, []byte(":"))
 		if bytes.Equal(nulrev, pair[1]) {
 			// null rev indicates this tag is marked for deletion
 			continue
 		}
 
-		idx := bytes.IndexByte(pair[0], 32) // space
-		v := NewVersion(string(pair[0][:idx])).Is(Revision(pair[1])).(PairedVersion)
+		// tip moves like a branch, so treat it that way
+		var v PairedVersion
+		if bytes.HasPrefix(line, []byte("tip")) {
+			v = NewBranch("tip").Is(Revision(pair[1])).(PairedVersion)
+		} else {
+			idx := bytes.IndexByte(pair[0], 32) // space
+			v = NewVersion(string(pair[0][:idx])).Is(Revision(pair[1])).(PairedVersion)
+		}
+
 		vlist = append(vlist, v)
 	}
 

vcs_source_test.go

@@ -491,6 +491,7 @@ func testHgSourceInteractions(t *testing.T) {
 			NewBranch("another").Is(Revision("b10d05d581e5401f383e48ccfeb84b48fde99d06")),
 			NewBranch("default").Is(Revision("3d466f437f6616da594bbab6446cc1cb4328d1bb")),
 			NewBranch("newbranch").Is(Revision("5e2a01be9aee942098e44590ae545c7143da9675")),
+			NewBranch("tip").Is(Revision("5e2a01be9aee942098e44590ae545c7143da9675")),
 		})
 		close(donech)
 	}()
@@ -500,6 +501,7 @@ func testHgSourceInteractions(t *testing.T) {
 		newDefaultBranch("default").Is(Revision("3d466f437f6616da594bbab6446cc1cb4328d1bb")),
 		NewBranch("another").Is(Revision("b10d05d581e5401f383e48ccfeb84b48fde99d06")),
 		NewBranch("newbranch").Is(Revision("5e2a01be9aee942098e44590ae545c7143da9675")),
+		NewBranch("tip").Is(Revision("5e2a01be9aee942098e44590ae545c7143da9675")),
 	})
 
 	<-donech