626b7c8493 fuzz: add scanblocks as safe for fuzzing (James O'Beirne)
94fe5453c7 test: rpc: add scanblocks functional test (Jonas Schnelli)
6ef2566b68 rpc: add scanblocks - scan for relevant blocks with descriptors (Jonas Schnelli)
a4258f6e81 rpc: move-only: consolidate blockchain scan args (James O'Beirne)
Pull request description:
Revives #20664. All feedback from the previous PR has either been responded to inline or incorporated here.
---
Major changes from Jonas' PR:
- consolidated arguments for scantxoutset/scanblocks
- substantial cleanup of the functional test
Here's the range-diff (`git range-diff master jonasschnelli/2020/12/filterblocks_rpc jamesob/2021-11-scanblocks`): https://gist.github.com/jamesob/aa4a975344209f0316444b8de2ec1d18
### Original PR description
> The `scanblocks` RPC call allows one to get relevant blockhashes from a set of descriptors by scanning all blockfilters in a given range.
>
> **Example:**
>
> `scanblocks start '["addr(<bitcoin_address>)"]' 661000` (returns relevant blockhashes for `<bitcoin_address>` from blockrange 661000->tip)
>
> ## Why is this useful?
> **Fast wallet rescans**: get the relevant blocks and only rescan those via `rescanblockchain getblockheader(<hash>)[height] getblockheader(<hash>)[height])`. A future PR may add an option to allow to provide an array of blockhashes to `rescanblockchain`.
>
> **prune wallet rescans**: (_needs additional changes_): together with a call to fetch blocks from the p2p network if they have been pruned, it would allow to rescan wallets back to the genesis block in pruned mode (relevant #15946).
>
> **SPV mode** (_needs additional changes_): it would be possible to build the blockfilterindex from the p2p network (rather then deriving them from the blocks) and thus allow some sort of hybrid-SPV mode with moderate bandwidth consumption (related #9483)
ACKs for top commit:
furszy:
diff re-ACK 626b7c8
Tree-SHA512: f84e4dcb851b122b39e9700c58fbc31e899cdcf9b587df9505eaf1f45578cc4253e89ce2a45d1ff21bd213e31ddeedbbcad2c80810f46755b30acc17b07e2873
bc2b1f0fe2