Fix NullPointerException in Exception Replay

jpbempel · jpbempel · commit bbfbd348e32e · 2026-04-28T10:23:14.000+02:00
make ThrowableState always instantiate the list of snpashots and mark
it final
diff --git a/dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/exception/ExceptionProbeManager.java b/dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/exception/ExceptionProbeManager.java
@@ -182,7 +182,7 @@ boolean hasExceptionStateTracked() {
 
   public static class ThrowableState {
     private final String exceptionId;
-    private List<Snapshot> snapshots;
+    private final List<Snapshot> snapshots = new ArrayList<>();
     private boolean snapshotSent;
 
     private ThrowableState(String exceptionId) {
@@ -198,13 +198,10 @@ public List<Snapshot> getSnapshots() {
     }
 
     public boolean isSampling() {
-      return snapshots != null && !snapshots.isEmpty();
+      return !snapshots.isEmpty();
     }
 
     public void addSnapshot(Snapshot snapshot) {
-      if (snapshots == null) {
-        snapshots = new ArrayList<>();
-      }
       snapshots.add(snapshot);
     }
 

Original file line number	Diff line number	Diff line change
`@@ -182,7 +182,7 @@ boolean hasExceptionStateTracked() {`
`182`	`182`
`183`	`183`	`public static class ThrowableState {`
`184`	`184`	`private final String exceptionId;`
`185`		`- private List<Snapshot> snapshots;`
	`185`	`+ private final List<Snapshot> snapshots = new ArrayList<>();`
`186`	`186`	`private boolean snapshotSent;`
`187`	`187`
`188`	`188`	`private ThrowableState(String exceptionId) {`
`@@ -198,13 +198,10 @@ public List<Snapshot> getSnapshots() {`
`198`	`198`	`}`
`199`	`199`
`200`	`200`	`public boolean isSampling() {`
`201`		`- return snapshots != null && !snapshots.isEmpty();`
	`201`	`+ return !snapshots.isEmpty();`
`202`	`202`	`}`
`203`	`203`
`204`	`204`	`public void addSnapshot(Snapshot snapshot) {`
`205`		`- if (snapshots == null) {`
`206`		`- snapshots = new ArrayList<>();`
`207`		`- }`
`208`	`205`	`snapshots.add(snapshot);`
`209`	`206`	`}`
`210`	`207`