Bitcoin Core v30.0 / v30.1 contain a known regression in the legacy (Berkeley DB) wallet migration code where, under rare conditions, migrating a single legacy wallet can delete all wallet directories on the same node. A fix is planned for v30.2.
I am trying to understand the technical root cause of this failure mode:
A) What filesystem or path-handling assumption failed during the migration?
B) Why did the deletion affect sibling wallet directories instead of being confined to the migrated wallet?
C) What conditions made this bug rare (e.g., multiple wallets, non-default datadir layouts, symlinks, or error paths)?
D) What change in v30 introduced this regression, and what class of test would have caught it pre-release?
I am ver interested in the mechanism, not attribution. Thx
