diff options
Diffstat (limited to 'src/main/java/com/google/devtools/build/lib')
-rw-r--r-- | src/main/java/com/google/devtools/build/lib/collect/IterablesChain.java | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/collect/IterablesChain.java b/src/main/java/com/google/devtools/build/lib/collect/IterablesChain.java index 69abf331cb..0286798e2a 100644 --- a/src/main/java/com/google/devtools/build/lib/collect/IterablesChain.java +++ b/src/main/java/com/google/devtools/build/lib/collect/IterablesChain.java @@ -18,7 +18,7 @@ import com.google.common.base.Joiner; import com.google.common.collect.AbstractIterator; import com.google.common.collect.ImmutableList; import com.google.common.collect.Iterables; - +import com.google.devtools.build.lib.collect.nestedset.NestedSet; import java.util.ArrayList; import java.util.HashSet; import java.util.Iterator; @@ -77,7 +77,11 @@ public final class IterablesChain<T> implements Iterable<T> { */ public Builder<T> add(Iterable<? extends T> iterable) { CollectionUtils.checkImmutable(iterable); - if (!Iterables.isEmpty(iterable)) { + // Avoid unnecessarily expanding a NestedSet. + boolean isEmpty = iterable instanceof NestedSet + ? ((NestedSet<?>) iterable).isEmpty() + : Iterables.isEmpty(iterable); + if (!isEmpty) { iterables.add(iterable); } return this; |