Enable load() statement in the WORKSPACE file.

RELNOTES[NEW]: Skylark macros are now enabled in WORKSPACE file.

Design document at https://docs.google.com/document/d/1jKbNXOVp2T1zJD_iRnVr8k5D0xZKgO8blMVDlXOksJg/preview

Fixes #337

--
MOS_MIGRATED_REVID=108860301

1 files changed, 39 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkImportLookupValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkImportLookupValue.java
index c298977f5f..3574e2b2e8 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkImportLookupValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkImportLookupValue.java
@@ -15,10 +15,14 @@ package com.google.devtools.build.lib.skyframe;
 
 import com.google.common.base.Preconditions;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.syntax.Environment.Extension;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
 
+import java.io.Serializable;
+import java.util.Objects;
+
 /**
  * A value that represents a Skylark import lookup result. The lookup value corresponds to
  * exactly one Skylark file, identified by an absolute {@link Label} {@link SkyKey} argument. The
@@ -55,10 +59,41 @@ public class SkylarkImportLookupValue implements SkyValue {
   }
 
   /**
-   * Returns a SkyKey to look up {@link Label} {@code importLabel}, which must be an absolute
-   * label.
+   * SkyKey for a Skylark import composed of the label of the Skylark extension and wether it is
+   * loaded from the WORKSPACE file or from a BUILD file.
    */
-  static SkyKey key(Label importLabel) {
-    return new SkyKey(SkyFunctions.SKYLARK_IMPORTS_LOOKUP, importLabel);  
+  @Immutable
+  public static final class SkylarkImportLookupKey implements Serializable {
+    public final Label importLabel;
+    public final boolean inWorkspace;
+
+    public SkylarkImportLookupKey(Label importLabel, boolean inWorkspace) {
+      Preconditions.checkNotNull(importLabel);
+      this.importLabel = importLabel;
+      this.inWorkspace = inWorkspace;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+      if (this == obj) {
+        return true;
+      }
+      if (!(obj instanceof SkylarkImportLookupKey)) {
+        return false;
+      }
+      SkylarkImportLookupKey other = (SkylarkImportLookupKey) obj;
+      return importLabel.equals(other.importLabel)
+          && inWorkspace == other.inWorkspace;
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(importLabel, inWorkspace);
+    }
+  }
+
+  static SkyKey key(Label importLabel, boolean inWorkspace) {
+    return new SkyKey(
+        SkyFunctions.SKYLARK_IMPORTS_LOOKUP, new SkylarkImportLookupKey(importLabel, inWorkspace));
   }
 }