Missing prometheus_tsdb_wal_corruptions_total metric in newer versions of Prometheus

[dbluxo]

Bug Report

What did you do?

Started Prometheus 2.5.0 (or v2.6.0-rc.0) with default config:
./prometheus --config.file=prometheus.yml

What did you expect to see?

This internal metric:

# HELP prometheus_tsdb_wal_corruptions_total Total number of WAL corruptions.
# TYPE prometheus_tsdb_wal_corruptions_total counter
prometheus_tsdb_wal_corruptions_total 0

prometheus/web/web.go

Line 626 in e3bdc46

case "prometheus_tsdb_wal_corruptions_total":

What did you see instead? Under which circumstances?

We did not see the prometheus_tsdb_wal_corruptions_total metric.
We did see the metric in Prometheus version 2.3.2

Environment

• System information:

  Linux 4.15.0-42-generic x86_64

[dbluxo]

prometheus/tsdb#471