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GHC 9.10.3 · lts/ghc-9.10.x · c74966e · 2026-09-27

Modulecabal-install-3.12.1.0Haskell2010

Distribution.Client.ProjectPlanning.SetupPolicy

Setup.hs script policy

Handling for Setup.hs scripts is a bit tricky, part of it lives in the solver phase, and part in the elaboration phase. We keep the helper functions for both phases together here so at least you can see all of it in one place.

There are four major cases for Setup.hs handling:

  1. build-type Custom with a custom-setup section

  2. build-type Custom without a custom-setup section

  3. build-type not Custom with cabal-version > $our-cabal-version

  4. build-type not Custom with cabal-version <= $our-cabal-version

It's also worth noting that packages specifying cabal-version: >= 1.23 or later that have build-type Custom will always have a custom-setup section. Therefore in case 2, the specified cabal-version will always be less than 1.23.

In cases 1 and 2 we obviously have to build an external Setup.hs script, while in case 4 we can use the internal library API.

  • 1 type
  • 3 values
valuemkDefaultSetupDeps
  1. :: Compiler
  2. -> Platform
  3. -> PackageDescription
  4. -> Maybe [Dependency]
#

Part of our Setup.hs handling policy is implemented by getting the solver to work out setup dependencies for packages. The solver already handles packages that explicitly specify setup dependencies, but we can also tell the solver to treat other packages as if they had setup dependencies. That's what this function does, it gets called by planPackages for all packages that don't already have setup dependencies.

The dependencies we want to add is different for each SetupScriptStyle.

Note in addition to adding setup dependencies, we also use addSetupCabalMinVersionConstraint (in planPackages) to require Cabal >= 1.20 for Setup scripts.

newtypenewtype NonSetupLibDepSolverPlanPackage
#

A newtype for SolverPlanPackage for which the dependency graph considers only dependencies on libraries which are NOT from setup dependencies. Used to compute the set of packages needed for profiling and dynamic libraries.

Constructors

Instances3IsNode, Package, Key