I think that if a reorg fails due to an error while disconnecting blocks, the node should shut down.

My thought is that if we are trying to switch to a more work chain and something goes wrong before we can even try to validate that more-work chain, then we have a problem that is not related to the chain we're trying to switch to but instead related to our own hardware or software; shutting down and having the user deal with the issue is better than continuing on, when we know there's a more work chain that we're unable to try validating.

This has recently come up on testnet, where unpatched nodes are unable to reorg from the invalid chain containing the duplicate-input-in-a-transaction block, but rather than crash or shutdown they are continuing on the invalid chain, with messages like this in the debug log:

```
ERROR: DisconnectTip(): DisconnectBlock 00000000210004840364b52bc5e455d888f164e4264a4fec06a514b67e9d5722 failed
```
CValidationState stateDummy; 
            if (!tx.HasWitness() && CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, false, txdata) &&
                !CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, txdata)) {
                
                state.SetCorruptionPossible();
            }
            return false; 
        }
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        unsigned int currentBlockScriptVerifyFlags = GetBlockScriptFlags(chainActive.Tip(), chainparams.GetConsensus());
        if (!CheckInputsFromMempoolAndCache(tx, state, view, pool, currentBlockScriptVerifyFlags, true, txdata)) {
            return error("%s: BUG! PLEASE REPORT THIS! CheckInputs failed against latest-block but not STANDARD flags %s, %s",
                    __func__, hash.ToString(), FormatStateMessage(state));
        }
        if (test_accept) {