Github user casidiablo commented on a diff in the pull request: https://github.com/apache/flink/pull/5182#discussion_r160139807 --- Diff: flink-metrics/flink-metrics-core/src/main/java/org/apache/flink/metrics/groups/UnregisteredMetricsGroup.java --- @@ -107,7 +107,7 @@ public MetricGroup addGroup(String key, String value) { @Override public Map<String, String> getAllVariables() { - return Collections.emptyMap(); + return new HashMap<>(); --- End diff -- I think it was before (tests were failing because I was using `...getAllVariables().put("shard_id")...`). I will revert and test.
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