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.

--
MOS_MIGRATED_REVID=102363438

1 files changed, 19 insertions, 11 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java
index 30f0c6a027..ce45ca2155 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java
@@ -20,6 +20,7 @@ import com.google.devtools.build.lib.packages.PackageFactory;
 import com.google.devtools.build.lib.packages.RuleClassProvider;
 import com.google.devtools.build.lib.packages.WorkspaceFactory;
 import com.google.devtools.build.lib.syntax.EvalException;
+import com.google.devtools.build.lib.syntax.Mutability;
 import com.google.devtools.build.lib.syntax.ParserInputSource;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -62,18 +63,25 @@ public class WorkspaceFileFunction implements SkyFunction {
     Path repoWorkspace = workspaceRoot.getRoot().getRelative(workspaceRoot.getRelativePath());
     Builder builder = new Builder(repoWorkspace,
         packageFactory.getRuleClassProvider().getRunfilesPrefix());
-    WorkspaceFactory parser = new WorkspaceFactory(
-        builder, packageFactory.getRuleClassProvider(), installDir.getPathString());
-    parser.parse(ParserInputSource.create(
-        ruleClassProvider.getDefaultWorkspaceFile(), new PathFragment("DEFAULT.WORKSPACE")));
-    if (!workspaceFileValue.exists()) {
-      return new PackageValue(builder.build());
-    }
+    try (Mutability mutability = Mutability.create("workspace %s", repoWorkspace)) {
+      WorkspaceFactory parser =
+          new WorkspaceFactory(
+              builder,
+              packageFactory.getRuleClassProvider(),
+              mutability,
+              installDir.getPathString());
+      parser.parse(
+          ParserInputSource.create(
+              ruleClassProvider.getDefaultWorkspaceFile(), new PathFragment("DEFAULT.WORKSPACE")));
+      if (!workspaceFileValue.exists()) {
+        return new PackageValue(builder.build());
+      }
 
-    try {
-      parser.parse(ParserInputSource.create(repoWorkspace));
-    } catch (IOException e) {
-      throw new WorkspaceFileFunctionException(e, Transience.TRANSIENT);
+      try {
+        parser.parse(ParserInputSource.create(repoWorkspace));
+      } catch (IOException e) {
+        throw new WorkspaceFileFunctionException(e, Transience.TRANSIENT);
+      }
     }
 
     return new PackageValue(builder.build());