Avoid NPEs in getTaskHistograms if it races with profiler start/stop.

PiperOrigin-RevId: 375036917
fweikert · May 21, 2021 · a64cd4a · a64cd4a
1 parent 2f0927a
commit a64cd4a
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java b/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
@@ -300,8 +300,8 @@ private void initHistograms() {
   // TODO(ulfjack): This returns incomplete data by design. Maybe we should return the histograms on
   // stop instead? However, this is currently only called from one location in a module, and that
   // can't call stop itself. What to do?
-  public ImmutableList<StatRecorder> getTasksHistograms() {
-    return ImmutableList.copyOf(tasksHistograms);
+  public synchronized ImmutableList<StatRecorder> getTasksHistograms() {
+    return isActive() ? ImmutableList.copyOf(tasksHistograms) : ImmutableList.of();
   }
 
   public static Profiler instance() {