Github user pnowojski commented on a diff in the pull request:
https://github.com/apache/flink/pull/4587#discussion_r160700659
--- Diff:
flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/NFA.java ---
@@ -150,16 +126,13 @@
*/
private boolean nfaChanged;
- public NFA(
- final TypeSerializer<T> eventSerializer,
+ public NFA(final TypeSerializer<T> eventSerializer,
final long windowTime,
final boolean handleTimeout) {
-
this.eventSerializer = eventSerializer;
--- End diff --
If you check all of the `NFA`'s `eventSerializer` usages, there are all in
the `extractCurrentMatches` method, which before your change was guarding
against `(eventSerializer == null)` condition. Thus (maybe unintentionally)
this class's `evenSerializer` field could be `@Nullable` or was supporting `new
NFA(null, 1, false)` calls. From what I have checked (by following up all of
the constructor invocations), there seems to be no code path for such
construction to happen at the moment, but adding
`checkNotNull(eventSerializer)` will guard against such mistakes in the future.
---
