Rollback of commit 0d1dc5537903a8c2ad56e66cee129b8f4d4e2592.

--
PiperOrigin-RevId: 144194956
MOS_MIGRATED_REVID=144194956

1 files changed, 41 insertions, 17 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkNestedSet.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkNestedSet.java
index df936692aa..fc78da5385 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkNestedSet.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkNestedSet.java
@@ -24,9 +24,12 @@ import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
 import com.google.devtools.build.lib.util.Preconditions;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Set;
+import javax.annotation.Nullable;
 
 /** A generic type safe NestedSet wrapper for Skylark. */
 @SkylarkModule(
@@ -82,41 +85,47 @@ public final class SkylarkNestedSet implements Iterable<Object>, SkylarkValue, S
 
   private final SkylarkType contentType;
   private final NestedSet<?> set;
+  @Nullable
+  private final List<Object> items;
+  @Nullable
+  private final List<NestedSet> transitiveItems;
 
   public SkylarkNestedSet(Order order, Object item, Location loc) throws EvalException {
-    this(SkylarkType.TOP, item, loc, new NestedSetBuilder<Object>(order));
+    this(order, SkylarkType.TOP, item, loc, null);
   }
 
   public SkylarkNestedSet(SkylarkNestedSet left, Object right, Location loc) throws EvalException {
-    this(
-        left.contentType,
-        right,
-        loc,
-        new NestedSetBuilder<Object>(left.getOrder()).addTransitive(left.set));
+    this(left.set.getOrder(), left.contentType, right, loc, left);
   }
 
   // This is safe because of the type checking
   @SuppressWarnings("unchecked")
-  private SkylarkNestedSet(
-      SkylarkType contentType, Object item, Location loc, NestedSetBuilder setBuilder)
-      throws EvalException {
+  private SkylarkNestedSet(Order order, SkylarkType contentType, Object item, Location loc,
+      @Nullable SkylarkNestedSet left) throws EvalException {
+
+    ArrayList<Object> items = new ArrayList<>();
+    ArrayList<NestedSet> transitiveItems = new ArrayList<>();
+    if (left != null) {
+      if (left.items == null) { // SkylarkSet created from native NestedSet
+        transitiveItems.add(left.set);
+      } else { // Preserving the left-to-right addition order.
+        items.addAll(left.items);
+        transitiveItems.addAll(left.transitiveItems);
+      }
+    }
     // Adding the item
     if (item instanceof SkylarkNestedSet) {
       SkylarkNestedSet nestedSet = (SkylarkNestedSet) item;
       if (!nestedSet.isEmpty()) {
         contentType = checkType(contentType, nestedSet.contentType, loc);
-        try {
-          setBuilder.addTransitive((NestedSet<Object>) nestedSet.set);
-        } catch (IllegalStateException e) {
-          // Order mismatch between item and setBuilder.
-          throw new EvalException(loc, e.getMessage());
-        }
+        transitiveItems.add(nestedSet.set);
       }
     } else if (item instanceof SkylarkList) {
+      // TODO(bazel-team): we should check ImmutableList here but it screws up genrule at line 43
       for (Object object : (SkylarkList) item) {
         contentType = checkType(contentType, SkylarkType.of(object.getClass()), loc);
         checkImmutable(object, loc);
-        setBuilder.add(object);
+        items.add(object);
       }
     } else {
       throw new EvalException(
@@ -125,7 +134,20 @@ public final class SkylarkNestedSet implements Iterable<Object>, SkylarkValue, S
               "cannot add value of type '%s' to a depset", EvalUtils.getDataTypeName(item)));
     }
     this.contentType = Preconditions.checkNotNull(contentType, "type cannot be null");
-    this.set = setBuilder.build();
+
+    // Initializing the real nested set
+    NestedSetBuilder<Object> builder = new NestedSetBuilder<>(order);
+    builder.addAll(items);
+    try {
+      for (NestedSet<?> nestedSet : transitiveItems) {
+        builder.addTransitive(nestedSet);
+      }
+    } catch (IllegalStateException e) {
+      throw new EvalException(loc, e.getMessage());
+    }
+    this.set = builder.build();
+    this.items = ImmutableList.copyOf(items);
+    this.transitiveItems = ImmutableList.copyOf(transitiveItems);
   }
 
   /**
@@ -150,6 +172,8 @@ public final class SkylarkNestedSet implements Iterable<Object>, SkylarkValue, S
     // This is here for the sake of FuncallExpression.
     this.contentType = Preconditions.checkNotNull(contentType, "type cannot be null");
     this.set = Preconditions.checkNotNull(set, "set cannot be null");
+    this.items = null;
+    this.transitiveItems = null;
   }
 
   /**