[HADOOP-16220] Add findbugs ignores for unjustified issues during update to guava to 27.0-jre in hadoop-project

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.4, 3.3.0, 3.2.1, 3.1.3
• Fix Version/s: 3.0.4, 3.3.0, 3.2.1, 3.1.3
• Hadoop Flags: Reviewed
• Assignee: Gabor Bota
• Reporter: Gabor Bota
• Created: 29/Mar/19 13:24
• Updated: 02/Apr/19 12:39
• Resolved: 01/Apr/19 04:53

Description

There are some findbugs issues with the guava update that seemed unjustified and should be fixed before the update:

• Null passed for non-null parameter of com.google.common.base.Preconditions.checkState(boolean, String, Object, Object, Object) in org.apache.hadoop.hdfs.qjournal.server.Journal.getPersistedPaxosData(long)
  In org/apache/hadoop/hdfs/qjournal/server/Journal.java:1064 we call

  Preconditions.checkState(ret != null &&
            ret.getSegmentState().getStartTxId() == segmentTxId,
            "Bad persisted data for segment %s: %s ; journal id: %s",
            segmentTxId, ret, journalId);
  

  for this call findbug assumes that Argument 4 might be null but must not be null, but Guava 27.0's com.google.common.base.Preconditions#checkState(boolean, java.lang.String, java.lang.Object, java.lang.Object, java.lang.Object) is annotated like the following:

    public static void checkState(
        boolean b,
        @Nullable String errorMessageTemplate,
        @Nullable Object p1,
        @Nullable Object p2,
        @Nullable Object p3) {
  

  so we have @Nullable on each parameter for the method. I don't see this warning as justified, or need to be fixed.

• Null passed for non-null parameter of com.google.common.base.Preconditions.checkArgument(boolean, String, Object) in org.apache.hadoop.hdfs.qjournal.server.JournalNode.getLogDir(String, String)
  In org/apache/hadoop/hdfs/qjournal/server/JournalNode.java:325 we call

      Preconditions.checkArgument(jid != null &&
          !jid.isEmpty(),
          "bad journal identifier: %s", jid);
  

  for this call findbug assumes that Argument 3 might be null but must not be null, but Guava 27.0's com.google.common.base.Preconditions#checkArgument(boolean, java.lang.String, java.lang.Object) is annotated like the following:

    public static void checkArgument(
        boolean b, @Nullable String errorMessageTemplate, @Nullable Object p1) {
  

  so we have @Nullable on argument 3, and that renders the assumption incorrect.

• Nullcheck of jid at line 346 of value previously dereferenced in org.apache.hadoop.hdfs.qjournal.server.JournalNode.getLogDir(String, String)
  This is about the assert jid != null; at JournalNode.java:346. I would leave it as is, it's not a redundant check, just additional information. (I'm not a fan of using assert in production code, but if it's there we can leave it).

Issue Links

• causes: HADOOP-16230 Correct findbug ignores for unjustified issues during update to guava to 27.0-jre in hadoop-project
• is required by: HADOOP-16210 Update guava to 27.0-jre in hadoop-project trunk
• links to: GitHub Pull Request #665