Wallet#add_credits uses return inside a with_lock block — credit grants can silently roll back depending on Rails version

[TalGruperFolloze]

Summary

lib/usage_credits/models/wallet.rb (~line 235) does return transaction from inside a with_lock do ... end block. with_lock opens a transaction, so this is a non-local return out of a transaction block — and Rails' behavior for that has changed several times across the version range this gem supports (rails >= 6.1).

Why it matters

Depending on the host app's Rails version and load_defaults, the same add_credits call either commits or silently rolls back:

Rails	Behavior on return out of a transaction
6.1 – 7.0	Emits DEPRECATION WARNING: Using return, break or throw to exit a transaction block is deprecated ... This results in the transaction being committed, but in the next release of Rails it will rollback. Silent rollback on 7.0.x was reported in rails/rails#45017.
7.1	Controlled by config.active_record.commit_transaction_on_non_local_return — true for apps on load_defaults 7.1, but apps still on older defaults get the rollback.
7.2+	Historical commit behavior restored; the config is deprecated.

So an app on 7.0, or on 7.1 without load_defaults 7.1, gets a silent rollback of every credit grant. There's no exception — add_credits still returns a Transaction object, so callers and callbacks see success — but the ledger row is gone. Nothing appears in the logs.

Every grant path routes through this: start_credit_period!, apply_credits_config_change!, add_credits!, and per-user give_credits. Wallets would read zero with no indication anything failed.

This is also exactly the case rubocop-rails' Rails/TransactionExitStatement cop flags, including its explicit note that with_lock implicitly opens a transaction.

Suggested fix

Delete the return keyword. transaction is already the last expression in the block, so the return value of the method is unchanged — it's a one-word change that makes the behavior identical and version-independent:

with_lock do
  # ...
  transaction   # was: return transaction
end

Two related suggestions:

1. Audit the rest of the codebase for other non-local exits (return / break / throw) inside with_lock or transaction blocks.
2. Consider enabling Rails/TransactionExitStatement in the gem's RuboCop config to catch regressions.

Definition of done

A spec that grants credits and then asserts the balance actually persists after the call — reloading the wallet and checking the row exists. Because the failure mode is silent and the method still returns a truthy Transaction, only a persistence assertion catches it.

Environment

• usage_credits 0.5.0 (latest published as of Aug 2026)
• Currently on Rails 6.1, preparing a Rails 7 upgrade

Happy to open a PR for the one-word change if that's helpful.