2052e3aa9a wallet: ignore chainStateFlushed notifications while attaching chain (Martin Zumsande)
Pull request description:
Fixes #24487
When a rescan is performed during `CWallet::AttachChain()` (e.g. when loading an old wallet) but this is interrupted by a shutdown signal, the wallet will currently stop the rescan, receive a `chainStateFlushed` signal, set the saved best block to the tip and shut down. At next startup, the rescan is not continued or repeated because of this. But some blocks have never been scanned by the wallet, which could lead to an incorrect balance.
Fix this by ignoring `chainStateFlushed` notifications until the chain is attached. Since `CWallet::chainStateFlushed` is being manually called by `AttachChain()` anyway after finishing with the rescan, it is not a problem if intermediate notifications are ignored.
Manual rescans started / aborted by the `rescanblockchain` / `abortrescan` RPCs are not affected by this.
I didn't choose alternative ways of fixing this issue that would delay the validationinterface registration or change anything else about the handling of `blockConnected` signals for the reasons mentioned in [this existing comment](https://github.com/bitcoin/bitcoin/blob/master/src/wallet/wallet.cpp#L2937-L2944).
ACKs for top commit:
achow101:
ACK 2052e3aa9a
ryanofsky:
Code review ACK 2052e3aa9a. This is a straightforward fix for the bug described in #24487 where a wallet could skip scanning blocks if is shut down in the middle of a sync and a chainStateFlushed notification was received during the sync. It would be nice to write a test for this but probably would be tricky to write.
w0xlt:
Code Review ACK 2052e3aa9a
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4cf9fa0b66