test_bitcoin: ./chain.h:261: uint256 CBlockIndex::GetBlockHash() const: Assertion `phashBlock != nullptr' failed. #27320

https://cirrus-ci.com/task/6024293113397248?logs=ci#L3199

Simulating node restart
2023-03-23T20:11:01.824273Z (mocktime: 2020-08-31T15:36:02Z) [test] [logging/timer.h:58] [Log] [bench] FlushStateToDisk: write block and undo data to disk started
2023-03-23T20:11:01.824318Z (mocktime: 2020-08-31T15:36:02Z) [test] [logging/timer.h:58] [Log] [bench] FlushStateToDisk: write block and undo data to disk completed (0.03ms)
2023-03-23T20:11:01.824330Z (mocktime: 2020-08-31T15:36:02Z) [test] [logging/timer.h:58] [Log] [bench] FlushStateToDisk: write block index to disk started
2023-03-23T20:11:01.825668Z (mocktime: 2020-08-31T15:36:02Z) [test] [logging/timer.h:58] [Log] [bench] FlushStateToDisk: write block index to disk completed (1.33ms)
2023-03-23T20:11:01.825686Z (mocktime: 2020-08-31T15:36:02Z) [test] [logging/timer.h:58] [Log] [bench] FlushStateToDisk: write coins cache to disk (0 coins, 0kB) started
2023-03-23T20:11:01.825704Z (mocktime: 2020-08-31T15:36:02Z) [test] [txdb.cpp:167] [BatchWrite] [coindb] Writing final batch of 0.00 MiB
2023-03-23T20:11:01.825719Z (mocktime: 2020-08-31T15:36:02Z) [test] [txdb.cpp:169] [BatchWrite] [coindb] Committed 0 changed transaction outputs (out of 0) to coin database...
2023-03-23T20:11:01.825732Z (mocktime: 2020-08-31T15:36:02Z) [test] [logging/timer.h:58] [Log] [bench] FlushStateToDisk: write coins cache to disk (0 coins, 0kB) completed (0.03ms)
2023-03-23T20:11:01.825744Z (mocktime: 2020-08-31T15:36:02Z) [test] [validationinterface.cpp:249] [ChainStateFlushed] [validation] Enqueuing ChainStateFlushed: block hash=696e92821f65549c7ee134edceeeeaaa4105647a3c4fd9f298c0aec0ab50425c
Performing Load/Verify/Activate of chainstate
test_bitcoin: ./chain.h:261: uint256 CBlockIndex::GetBlockHash() const: Assertion `phashBlock != nullptr' failed.
make[3]: *** [Makefile:21821: test/validation_chainstatemanager_tests.cpp.test] Error 1

On master @ 23056436461a8b3af1a504b9638c48e8c8170652

maybe not a cosmic ray after all (#26613)

I think the following may be happening: In the failed run, there is an UpdatedBlockTip scheduled in line 3169 that has not been processed yet:

2023-03-23T20:11:01.813759Z (mocktime: 2020-08-31T15:36:01Z) [test] [validationinterface.cpp:201] [UpdatedBlockTip][validation] Enqueuing UpdatedBlockTip: new block hash=4fe08ff1d78843f1b6f0d2b80fee9af49b3c945368e585b8aed1807c89d14804 fork block

Next, the test calls SimulateNodeRestart(), which resets the ChainstateManager and creates a new one. At last, the scheduler thread attempts to process the UpdatedBlockTip event, but the pointer to the CBlockIndex is no longer valid.

If that makes sense, a call to SyncWithValidationInterfaceQueue() within SimulateNodeRestart() might fix this - will open a PR.