Readability and cyclomatic complexity of database transaction code

Question

I consider these two options exactly the same. I prefer the first one but I'm not sure if it's better than the second option in terms of cyclomatic complexity or readability.

Assuming that this is not pure Ruby and I can call to the try method.

existing_transaction = database.find_transaction_by_id(transaction.id)
database.create_transaction(transaction) unless existing_transaction
database.update_transaction(transaction) unless existing_transaction.try(:processed)

existing_transaction = database.find_transaction_by_id(transaction.id)
if existing_transaction
 unless existing_transaction.processed
 database.update_transaction(transaction)
 end
else
 database.create_transaction(transaction)
end

Answer 1

It's obviously subjective, but IMHO inline conditionals make code harder to understand, indentation is very important. So I'd definitely take the second approach, but writing it differently to use only one indentation level:

existing_transaction = database.find_transaction_by_id(transaction.id)
if !existing_transaction
 database.create_transaction(transaction)
elsif !existing_transaction.processed
 database.update_transaction(transaction)
end

Answer 2

I would actually take a mixed approach:

if existing_transaction
 database.update_transaction(transaction) unless existing_transaction.processed
else
 database.create_transaction(transaction)
end

This way the code is more readable than the first option, but more succinct than the second option.

• Arturo Herrero: This is exactly my solution wrote with unless inlined.
• Uri Agassi: Yes, it is - it just reads better IMHO