Refactor Skylark Environment-s

Make Environment-s freezable: Introduce a class Mutability
as a revokable capability to mutate objects in an Environment.
For now, only Environment-s carry this capability.
Make sure that every Mutability is revoked in the same function that creates it,
so no Environment is left open for modification after being created and exported;
exceptions for tests, the shell and initialization contexts.

Unify Environment, SkylarkEnvironment and EvaluationContext into Environment.
Have a notion of Frame for the bindings + parent + mutability.
Replace the updateAndPropagate mechanism by a dynamicFrame.
Simplify ValidationEnvironment, that is now always deduced from the Environment.

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MOS_MIGRATED_REVID=102363438

1 files changed, 12 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/events/Location.java b/src/main/java/com/google/devtools/build/lib/events/Location.java
index 74b04a913a..1b9110d664 100644
--- a/src/main/java/com/google/devtools/build/lib/events/Location.java
+++ b/src/main/java/com/google/devtools/build/lib/events/Location.java
@@ -149,6 +149,18 @@ public abstract class Location implements Serializable {
   }
 
   /**
+   * Returns a line corresponding to the position denoted by getStartOffset.
+   * Returns null if this information is not available.
+   */
+  public Integer getStartLine() {
+    LineAndColumn lac = getStartLineAndColumn();
+    if (lac == null) {
+      return null;
+    }
+    return lac.getLine();
+  }
+
+  /**
    * Returns a (line, column) pair corresponding to the position denoted by
    * getEndOffset.  Returns null if this information is not available.
    */