Avoid double snapshots for Exception Replay

As Exception replay is supported by default for intermediate spans
we can end up in a situation where 2 spans are attaching the same
exception with the snapshots. in that case
DebuggerContext::handleException is called twice, once for each span
and we are also sending the same snapshots to the backend while only
one version is necessary and we tag it to the according spans.
We can just make sure we are sending the snapshots only once.

Author: jpbempel

dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/exception/DefaultExceptionDebugger.java

@@ -158,10 +158,13 @@ private static void processSnapshotsAndSetTags(
       String tagName = String.format(SNAPSHOT_ID_TAG_FMT, frameIndex);
       span.setTag(tagName, snapshot.getId());
       LOGGER.debug("add tag to span[{}]: {}: {}", span.getSpanId(), tagName, snapshot.getId());
-      DebuggerAgent.getSink().addSnapshot(snapshot);
+      if (!state.isSnapshotSent()) {
+        DebuggerAgent.getSink().addSnapshot(snapshot);
+      }
       snapshotAssigned = true;
     }
     if (snapshotAssigned) {
+      state.markAsSnapshotSent();
       span.setTag(DD_DEBUG_ERROR_EXCEPTION_ID, state.getExceptionId());
       LOGGER.debug(
           "add tag to span[{}]: {}: {}",

dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/exception/ExceptionProbeManager.java

@@ -183,6 +183,7 @@ boolean hasExceptionStateTracked() {
   public static class ThrowableState {
     private final String exceptionId;
     private List<Snapshot> snapshots;
+    private boolean snapshotSent;
 
     private ThrowableState(String exceptionId) {
       this.exceptionId = exceptionId;
@@ -206,5 +207,13 @@ public void addSnapshot(Snapshot snapshot) {
       }
       snapshots.add(snapshot);
     }
+
+    public boolean isSnapshotSent() {
+      return snapshotSent;
+    }
+
+    public void markAsSnapshotSent() {
+      snapshotSent = true;
+    }
   }
 }