Roll forward fix of global var shadow detection

RELNOTES[INC]: Skylark: It is an error to shadow a global variable with a local variable after the global has already been accessed in the function.

--
MOS_MIGRATED_REVID=130014492

2 files changed, 16 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Environment.java b/src/main/java/com/google/devtools/build/lib/syntax/Environment.java
index 2aab8811b2..ec504a06ec 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Environment.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Environment.java
@@ -222,12 +222,14 @@ public final class Environment implements Freezable {
         FuncallExpression caller,
         Frame lexicalFrame,
         Frame globalFrame,
+        Set<String> knownGlobalVariables,
         boolean isSkylark) {
       this.continuation = continuation;
       this.function = function;
       this.caller = caller;
       this.lexicalFrame = lexicalFrame;
       this.globalFrame = globalFrame;
+      this.knownGlobalVariables = knownGlobalVariables;
       this.isSkylark = isSkylark;
     }
   }
@@ -369,7 +371,8 @@ public final class Environment implements Freezable {
    */
   void enterScope(BaseFunction function, FuncallExpression caller, Frame globals) {
     continuation =
-        new Continuation(continuation, function, caller, lexicalFrame, globalFrame, isSkylark);
+        new Continuation(continuation, function, caller, lexicalFrame, globalFrame,
+            knownGlobalVariables, isSkylark);
     lexicalFrame = new Frame(mutability(), null);
     globalFrame = globals;
     knownGlobalVariables = new HashSet<>();
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java b/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java
index d5d393702b..3451238e01 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java
@@ -120,6 +120,18 @@ public class FunctionTest extends EvaluationTestCase {
   }
 
   @Test
+  public void testFunctionDefLocalVariableReferencedInCallBeforeAssignment() throws Exception {
+    checkEvalErrorContains("Variable 'a' is referenced before assignment.",
+        "def dummy(x):",
+        "  pass",
+        "a = 1",
+        "def func():",
+        "  dummy(a)",
+        "  a = 2",
+        "func()\n");
+  }
+
+  @Test
   public void testFunctionDefLocalVariableReferencedAfterAssignment() throws Exception {
     eval("a = 1",
         "def func():",