cabal-version:   3.0
name:            th-lock
version:         0.0.4
license:         BSD-3-Clause
license-file:    LICENSE
category:        Development
author:          Daniil Iaitskov <dyaitskov@gmail.com>
maintainer:      Daniil Iaitskov <dyaitskov@gmail.com>
stability:       experimental
synopsis:        Serialize compilation of modules with TH code modifing shared state
homepage:        https://github.com/yaitskov/th-lock
bug-reports:     https://github.com/yaitskov/th-lock/issues
build-type:      Simple
description:
    Recent GHC versions with option @-j\<N>@ where @N@ greater than 1 can
    build modules concurrently. Usually it is cool thing, because build time
    drops, but there is a drawback in form of problems with TH code
    maintaining a shared state.
    
    I encountered such issue while running tests for
    <https://hackage.haskell.org/package/trace-embrace trace-embrace>
    package. Package TH code has a shared state (immutable configuration
    file loaded once), which is not supposed to change after loading, but
    tests require to cover all cases\/branches and achieving this in the
    scope of a single cabal test-suit leads to inconsistencies.
    
    Spreading tests among multiple test suits cause code duplication and
    looks less elegant.
    
    Compilation of conflicting modules can be serialized with
    <https://hackage.haskell.org/package/th-lock/docs/Language-Haskell-TH-Lock.html#v:ensureSerialCompilationVerbose ensureSerialCompilationVerbose>.
    
    > {-# LANGUAGE TemplateHaskell #-}
    > module ModuleA where
    >
    > import Language.Haskell.TH.Lock
    >
    > ensureSerialCompilationVerbose
    
    ________________________________________________________________________
    
    > {-# LANGUAGE TemplateHaskell #-}
    > module ModuleB where
    >
    > import Language.Haskell.TH.Lock
    >
    > ensureSerialCompilationVerbose

tested-with:
  GHC == 9.10.1
extra-doc-files:
  changelog.md
library
  build-depends:
    base < 5,
    template-haskell < 2.24.0.0,

  exposed-modules:
    Language.Haskell.TH.Lock

  ghc-options: -Wall
  hs-source-dirs: src
  default-language: Haskell2010
  default-extensions:
    FlexibleContexts
    FlexibleInstances
    ImportQualifiedPost
    LambdaCase
    TemplateHaskell

test-suite test
  type: exitcode-stdio-1.0
  main-is: Driver.hs
  other-modules:
    Discovery
    Paths_th_lock
    Tests.Language.Haskell.TH.Lock.State
    Tests.Language.Haskell.TH.Lock.ModuleA
    Tests.Language.Haskell.TH.Lock.ModuleB
    Tests.Language.Haskell.TH.Lock.ModuleC
    Tests.Language.Haskell.TH.Lock.ModuleD
    Tests.Language.Haskell.TH.Lock.ModuleE
    Tests.Language.Haskell.TH.Lock.ModuleF
    Tests.Language.Haskell.TH.Lock.ModuleG
    Tests.Language.Haskell.TH.Lock.ModuleH
    Tests.Language.Haskell.TH.Lock.ModuleI
    Tests.Language.Haskell.TH.Lock.ModuleJ
    Tests.Language.Haskell.TH.Lock.ModuleX
    Tests.Language.Haskell.TH.Lock.ModuleY
    Tests.Language.Haskell.TH.Lock.ModuleZ
  autogen-modules:
    Paths_th_lock
  hs-source-dirs:
    test
  default-extensions:
    FlexibleContexts
    ImportQualifiedPost
    LambdaCase
    OverloadedLabels
    RecordWildCards
    ScopedTypeVariables
    TemplateHaskell
  ghc-options: -Wall -rtsopts -threaded -main-is Driver
  build-depends:
      base
    , tasty
    , tasty-discover
    , tasty-hunit
    , tasty-quickcheck
    , template-haskell
    , th-lock
  default-language: Haskell2010

source-repository head
  type:     git
  location: https://github.com/yaitskov/th-lock.git