Restart at most once when prepopulating repository rule environment

src/main/java/com/google/devtools/build/lib/bazel/repository/starlark/StarlarkRepositoryContext.java

@@ -516,43 +516,55 @@ public String toString() {
  * potentially more expensive operations.
  */
  // TODO(wyv): somehow migrate this to the base context too.
- public void enforceLabelAttributes() throws EvalException, InterruptedException {
+ public void enforceLabelAttributes() throws EvalException, InterruptedException, NeedsSkyframeRestartException {
  // TODO: If a labels fails to resolve to an existing regular file, we do not add a dependency on
  // that fact - if the file is created later or changes its type, it will not trigger a rerun of
  // the repository function.
  StructImpl attr = getAttr();
+ // Batch restarts as they are expensive
+ boolean needsRestart = false;
  for (String name : attr.getFieldNames()) {
  Object value = attr.getValue(name);
  if (value instanceof Label) {
- dependOnLabelIgnoringErrors((Label) value);
+ if (dependOnLabelIgnoringErrors((Label) value)) {
+ needsRestart = true;
+ }
  }
  if (value instanceof Sequence) {
  for (Object entry : (Sequence) value) {
  if (entry instanceof Label) {
- dependOnLabelIgnoringErrors((Label) entry);
+ if (dependOnLabelIgnoringErrors((Label) entry)) {
+ needsRestart = true;
+ }
  }
  }
  }
  if (value instanceof Dict) {
  for (Object entry : ((Dict) value).keySet()) {
  if (entry instanceof Label) {
- dependOnLabelIgnoringErrors((Label) entry);
+ if (dependOnLabelIgnoringErrors((Label) entry)) {
+ needsRestart = true;
+ }
  }
  }
  }
  }
+
+ if (needsRestart) {
+ throw new NeedsSkyframeRestartException();
+ }
  }
 
- private void dependOnLabelIgnoringErrors(Label label)
- throws InterruptedException, NeedsSkyframeRestartException {
+ private boolean dependOnLabelIgnoringErrors(Label label) throws InterruptedException {
  try {
  getPathFromLabel(label);
  } catch (NeedsSkyframeRestartException e) {
- throw e;
+ return true;
  } catch (EvalException e) {
  // EvalExceptions indicate labels not referring to existing files. This is fine,
  // as long as they are never resolved to files in the execution of the rule; we allow
  // non-strict rules.
  }
+ return false;
  }
 }