743abbcbde refactor: inline constant return value of `BlockTreeDB::WriteBatchSync` and `BlockManager::WriteBlockIndexDB` and `BlockTreeDB::WriteFlag` (Lőrinc)
e030240e90 refactor: inline constant return value of `CDBWrapper::Erase` and `BlockTreeDB::WriteReindexing` (Lőrinc)
cdab9480e9 refactor: inline constant return value of `CDBWrapper::Write` (Lőrinc)
d1847cf5b5 refactor: inline constant return value of `TxIndex::DB::WriteTxs` (Lőrinc)
50b63a5698 refactor: inline constant return value of `CDBWrapper::WriteBatch` (Lőrinc)
Pull request description:
Related to https://github.com/bitcoin/bitcoin/pull/31144#discussion_r2223587480
### Summary
`WriteBatch` always returns `true` - the errors are handled by throwing `dbwrapper_error` instead.
### Context
This boolean return value of the `Write` methods is confusing because it's inconsistent with `CDBWrapper::Read`, which catches exceptions and returns a boolean to indicate success/failure. It's bad that `Read` returns and `Write` throws - but it's a lot worse that `Write` advertises a return value when it actually communicates errors through exceptions.
### Solution
This PR removes the constant return values from write methods and inlines `true` at their call sites. Many upstream methods had boolean return values only because they were propagating these constants - those have been cleaned up as well.
Methods that returned a constant `true` value that now return `void`:
- `CDBWrapper::WriteBatch`, `CDBWrapper::Write`, `CDBWrapper::Erase`
- `TxIndex::DB::WriteTxs`
- `BlockTreeDB::WriteReindexing`, `BlockTreeDB::WriteBatchSync`, `BlockTreeDB::WriteFlag`
- `BlockManager::WriteBlockIndexDB`
### Note
`CCoinsView::BatchWrite` (and transitively `CCoinsViewCache::Flush` & `CCoinsViewCache::Sync`) were intentionally not changed here. While all implementations return `true`, the base `CCoinsView::BatchWrite` returns `false`. Changing this would cause `coins_view` tests to fail with:
> terminating due to uncaught exception of type std::logic_error: Not all unspent flagged entries were cleared
We can fix that in a follow-up PR.
ACKs for top commit:
achow101:
ACK 743abbcbde
janb84:
ACK 743abbcbde
TheCharlatan:
ACK 743abbcbde
sipa:
ACK 743abbcbde
Tree-SHA512: b2a550bff066216f1958d2dd9a7ef6a9949de518cc636f8ab9c670e0b7a330c1eb8c838e458a8629acb8ac980cea6616955cd84436a7b8ab9096f6d648073b1e
a4e96cae7d