* Split the database trait into read and transactions.
The transaction traits will encapsulate all database changes and also expect
READ-and-lock operations to read and lock records from the database for
exclusive access, thereby avoiding race conditions.
The Transaction trait expects a `rollback` operation on Drop unless the
transaction has been committed.
* fix: melt quote duplicate error
This change stops a second melt quote from being created
if there is an existing valid melt quote for an invoice already.
If the first melt quote has expired then we allow for a new melt quote to be created.
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Co-authored-by: thesimplekid <tsk@thesimplekid.com>
Bug: https://github.com/cashubtc/cdk/actions/runs/15683152414/job/44190084378?pr=822#step:5:19212
Reason: a race condition between removing proofs while melting and the quote states being updated.
Solution:
1. Error on duplicate proofs
2. Read quote when updating to avoid race conditions and rollbacks
Real solution: A transaction trait in the storage layer. That is coming next
Add a strict set of updates to prevent incorrect state changes and correct
usage. Supporting the transaction at the trait level prevented some cases, but
having a strict set of state change flows is better.
This bug was found while developing the signatory. The keys are read from
memory, triggering race conditions at the database, and some `Pending` states
are selected (instead of just selecting `Unspent`).
This PR also introduces a set of generic database tests to be executed for all
database implementations, this test suite will make sure writing and
maintaining new database drivers
- MintKeysDatabase
- MintQuotesDatabase
- MintProofsDatabase
- MintSignaturesDatabase
This commit splits the MintDatabase trait with 30+ methods into a series
of smaller traits, each dedicate to a specific subsystem of the mint
service.
