HBASE-30169 Split completed parent region added to RIT list on host RS and master crash

[Umeshkumar9414]

• Bug: When a host RegionServer and master crashes, regionCrashed() blindly added all hosted regions to RIT, including split-completed parent regions that should never be reassigned.
  • Fix: Added isSplitOrMerged() guard in regionCrashed() to skip split/merged regions. Extracted isSplitOrMerged() and isReplica() helpers to reduce duplication with handleRegionStateNodeOperation().
  • Removed broken isRegionInTransition(RegionInfo) API — RegionInfo.COMPARATOR considers offline/split flags, so lookups failed when those flags differed between the query and stored instance. Replaced
    with encoded-name-based lookup in test utility.
  • Added test testRITWithSplitTableRegion — splits a region, crashes the hosting RS, restarts the master, and verifies the split parent is NOT in the RIT list.

[Copilot]

Pull request overview

Fixes an assignment tracking bug where split/merged parent regions could be incorrectly added to the master’s Regions-In-Transition (RIT) list during RegionServer crash handling, especially across master restarts. This improves correctness of assignment state tracking and adds regression coverage for the crash + master restart scenario.

Changes:

• Skip adding split/merged (and replica) regions to RIT during regionCrashed, and refactor shared guards into helpers.
• Remove the broken AssignmentManager.isRegionInTransition(RegionInfo) API and replace test checks with an encoded-name-based lookup helper.
• Add a regression test that splits a region, expires the hosting RS, restarts the master, and verifies the split parent is not in RIT.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java	Updates tests to use the new encoded-name-based RIT check utility.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/assignment/TestRegionSplit.java	Adds regression test for split-parent not appearing in RIT after RS+master crash/restart; modernizes a few assertions.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/assignment/AssignmentTestingUtil.java	Introduces encoded-name-based isRegionInTransition helper and updates existing wait helper to use it.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionInTransitionTracker.java	Adds split/merged guard in regionCrashed, extracts helper predicates, and removes the public containsKey-based RIT query method.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java	Removes the now-deleted isRegionInTransition(RegionInfo) API.

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[Umeshkumar9414]

Failing test is related to compaction. Unrelated to PR. Can look seperatly later.

[Umeshkumar9414]

@virajjasani , @Apache9 is there any concern on this PR or can we merge this ?

[virajjasani]

Left minor nits, +1 otherwise

[virajjasani]

After this, can we also check for region[0] to be split?
e.g.

    assertTrue(UTIL.getHBaseCluster().getMaster()
      .getAssignmentManager().getRegionStates().getRegionState(regions[0]).isSplit());

[Umeshkumar9414]

instead of this I am using getOrCreateRegionStateNode(regions[0]).isSplit() as it do both the necessary check for split

[virajjasani]

same here after this? check for region[0] being split and offline?

[Umeshkumar9414]

added

[Umeshkumar9414]

PR for branch-2 : #8350
for branch-2.6 : #8351
for branch-2.5 : #8352