[CASSANDRA-15142] Fix errors on repairing empty keyspace

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-alpha2, 4.0
• Component/s: Consistency/Repair, Tool/nodetool
• Bug Category: Correctness - API / Semantic Implementation
• Severity: Low
• Complexity: Low Hanging Fruit
• Discovered By: User Report
• Platform: All
• Since Version: 5.0

Source Control Link

https://github.com/apache/cassandra/commit/5bc7a375a3cac85e79543e7e30d620faeb891955

Test and Documentation Plan

CircleCI

• Assignee: Stefan Podkowinski
• Reporter: Stefan Podkowinski

Authors

Stefan Podkowinski

Reviewers

Michael Semb Wever

• Created: 27/May/19 11:13
• Updated: 07/Mar/23 11:52
• Resolved: 09/Oct/19 09:07

Description

Running repairs on empty keyspaces will produce a rather confusing error in trunk:

ERROR [Repair-Task:1] 2019-05-24 10:36:20,323 RepairRunnable.java:274 - Repair 014607d0-7dff-11e9-9256-158db058ccc5 failed:
java.lang.IllegalArgumentException: repair sessions cannot operate on multiple keyspaces
▸  at com.google.common.base.Preconditions.checkArgument(Preconditions.java:135)
▸  at org.apache.cassandra.service.ActiveRepairService$ParentRepairSession.<init>(ActiveRepairService.java:566)
▸  at org.apache.cassandra.service.ActiveRepairService.registerParentRepairSession(ActiveRepairService.java:484)
▸  at org.apache.cassandra.service.ActiveRepairService.prepareForRepair(ActiveRepairService.java:395)
▸  at org.apache.cassandra.repair.RepairRunnable.runMayThrow(RepairRunnable.java:269)
▸  at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
▸  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
▸  at java.util.concurrent.FutureTask.run(FutureTask.java:266)
▸  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
▸  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
▸  at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
▸  at java.lang.Thread.run(Thread.java:748)

Let's ignore empty keyspaces and return a success return status instead.