Is `balance_for_locked_account` necessary?

[ghiculescu]

Thanks for sharing this great gem. I have been diving deep into the code and trying to understand its internals. One question I can't work out is is if balance_for_locked_account is necessary.

diff --git a/lib/double_entry/transfer.rb b/lib/double_entry/transfer.rb
index a846f90..4eb1de4 100644
--- a/lib/double_entry/transfer.rb
+++ b/lib/double_entry/transfer.rb
@@ -98,8 +98,8 @@ module DoubleEntry
     def create_lines(amount, code, detail, from_account, to_account, metadata)
       credit, debit = Line.new, Line.new

-      credit_balance = Locking.balance_for_locked_account(from_account)
-      debit_balance  = Locking.balance_for_locked_account(to_account)
+      credit_balance = AccountBalance.find_by_account(from_account, lock: true)
+      debit_balance  = AccountBalance.find_by_account(to_account, lock: true)

       credit_balance.update_attribute :balance, credit_balance.balance - amount
       debit_balance.update_attribute :balance, debit_balance.balance + amount

With this change, on Ruby 3.3, all tests and the jackhammer pass for me, using Postgres. (I ran the jackhammer with threads, I couldn't get it to run with processes, maybe the issue is there.)

It's obviously not a critical part of the code but it does add a little bit of extra indirection, and as far as I can tell it's not necessary, as long as Locking.lock_accounts wraps around this code.

[runlevel5]

@ghiculescu I am new to the lock property so unsure how it works. One way to find out, could you please check the SQL they AR generated? If the SQL queries are the same, I think we do not need Locking.balance_for_locked_account

[ghiculescu]

The same SQL would get run either way, because I just lifted that method from here:

double_entry/lib/double_entry/locking.rb

Line 152 in dfdf61d

account_balances = @accounts.map { |account| AccountBalance.find_by_account(account, lock: true) }

[runlevel5]

@ghiculescu I guess the intention is to use one centralised helper for the job.