Database transaction rollback failed with assertion

[kdeme]

Error: unhandled exception: /home/deme/.nimble/pkgs/eth-1.0.0/eth/trie/db.nim(145, 12) `t.db.mostInnerTransaction == t and t.state == Pending` 
Async traceback:
Exception message: /home/deme/.nimble/pkgs/eth-1.0.0/eth/trie/db.nim(145, 12) `t.db.mostInnerTransaction == t and t.state == Pending` 
Exception type: [AssertionError]

Looks like the processing of the block failed but the dispose/rollback (https://github.com/status-im/nimbus/blob/master/nimbus/p2p/chain.nim#L40) failed due to the assertion above.

[kdeme]

After further testing I've seen this two more times occur right when the file limit was reached, see here: status-im/nim-eth#85 . So it looks like a side effect of that.

I've not fully investigated this. But my first thought was that perhaps when something goes wrong in commit (e.g. put fails as it can't open a new file or so), this would mess up the mostInnerTransaction versus the t.state == Pending. But looking further I believe such error would actually raise Exception which should not be caught.

[kdeme]

Closing this until it is seen also under normal circumstances