jfischoff / pg-transact

Another postgresql-simple transaction monad

pg-transact

pg-transact's Issues

`abort`s interface should be `abort :: DBT m a`

Be able to pass in config options

Move per file extensions to cabal

Generalize `rollback` and related queries to use DBT

Add abort

Remove MonadThrow constraint from queryOne

First thanks for this nice little lib 👍

In the latest version, queryOne and queryOne_ got introduced however they require a MonadThrow m whereas query does not.

This means that if I want to use queryOne in a function, I must add MonadThrow to that functions and all functions calling it.
I don't see any good reason to have MonadThrow in the first place, so do you think it would be possible to remove it?

I need use the hspec-monadthrow library in the tests

It is annoying to not be able to user shouldThrow directly in the DBT monad.

Speed up the tests

The tests create way to many databases then appear necessary. Unsure of important it is to test transaction are committed in every test.

The interface should be build around a `MonadReader Connection m` monad

Not everything needs the DBT transactional semantics. postgresql-simple-queue does not need to use savepoints. I want to be able to code against an interface that can use DBT or something similar like ReaderT Conn IO which is probably a more performant monad for postgresql-simple-queue (assuming the savepoints are hurting performance).

Remove extra ROLLBACK in abort

Preparing pg-transact 0.3.2.0

With #19 merged, it may be time to think about a new release. pg-transact-hspec will need this patch for its own CI.

@jfischoff Is there anything you'd like to make sure we include in this release?

Test failures on Stackage nightly

Full log

Database.PostgreSQL.Transact
  TransactionSpec
    execute_ happen path succeeds FAILED [1]
    execute_ rollbacks on exception
     # PENDING: exception in beforeAll-hook (see previous failure)
    afterAll-hook FAILED [2]
    multiple execute_'s succeed FAILED [3]
    throwM causes a rollback FAILED [4]
    query recovers when exception is caught FAILED [5]
    multiple catch statements work correctly FAILED [6]
    alternate branches can also have savepoints FAILED [7]
    releasing silently fails if the transaction errors FAILED [8]

Failures:

  test/Database/PostgreSQL/TransactSpec.hs:65: 
  1) Database.PostgreSQL.Transact.TransactionSpec execute_ happen path succeeds
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.
hs:24:5-16))

  2) Database.PostgreSQL.Transact.TransactionSpec afterAll-hook
       uncaught exception: Result (Pending (Just "exception in beforeAll-hook (see previous failure)"))

  test/Database/PostgreSQL/TransactSpec.hs:82: 
  3) Database.PostgreSQL.Transact.TransactionSpec multiple execute_'s succeed
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.hs:24:5-16))

  test/Database/PostgreSQL/TransactSpec.hs:89: 
  4) Database.PostgreSQL.Transact.TransactionSpec throwM causes a rollback
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.hs:24:5-16))

  test/Database/PostgreSQL/TransactSpec.hs:98: 
  5) Database.PostgreSQL.Transact.TransactionSpec query recovers when exception is caught
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.hs:24:5-16))

  test/Database/PostgreSQL/TransactSpec.hs:108: 
  6) Database.PostgreSQL.Transact.TransactionSpec multiple catch statements work correctly
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.hs:24:5-16))

  test/Database/PostgreSQL/TransactSpec.hs:121: 
  7) Database.PostgreSQL.Transact.TransactionSpec alternate branches can also have savepoints
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.hs:24:5-16))

  test/Database/PostgreSQL/TransactSpec.hs:133: 
  8) Database.PostgreSQL.Transact.TransactionSpec releasing silently fails if the transaction errors
       uncaught exception: IOException of type UserError (user error (Pattern match failure in do expression at test/Database/PostgreSQL/TransactSpec.hs:24:5-16))

Randomized with seed 1794480295

Missing test to show that nesting `rollback` works

This is key advantage to rollback compared to abort. I should test it works ... since I am documenting that it works.

`MonadError` instance

I've found myself needing to interleave the possiblity of errors within DBT. For now, I use lift . throwError to throw errors, and use runExceptT just before running the transaction.

Implementing MonadError e m => MonadError e (DBT m) is trivial (with GeneralizedNewtypeDeriving for instance), but I'm not 100% sure about the semantics wrt transactions.

Do you think such an instance would make sense, or that it would give rise to dangerous things?
If it makes sense, I can open a PR to add it.

Add benchmarks