Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC

Commits:

• a8aa1868
  by Ilias Tsitsimpis at 2026-03-06T06:26:29-05:00

  Fix determinism of linker arguments
  
  The switch from Data.Map to UniqMap in 3b5be05ac29 introduced
  non-determinism in the order of packages passed to the linker.
  
  This resulted in non-reproducible builds where the DT_NEEDED entries in
  dynamic libraries were ordered differently across builds.
  
  Fix the regression by explicitly sorting the package list derived from
  UniqMap.
  
  Fixes #26838
  

1 changed file:

• compiler/GHC/Unit/State.hs

Changes:

 import Control.Monad

 import Data.Graph (stronglyConnComp, SCC(..))

 import Data.Char ( toUpper )

-import Data.List ( intersperse, partition, sortBy, sortOn )

+import Data.List ( intersperse, partition, sortBy, sortOn, sort )

 import Data.Set (Set)

 import Data.Monoid (First(..))

 import qualified Data.Semigroup as Semigroup

   -- NB: preload IS important even for type-checking, because we

   -- need the correct include path to be set.

   --

-  let preload1 = nonDetKeysUniqMap (filterUniqMap (isJust . uv_explicit) vis_map)

+  -- NB: Sorting keys here to ensure a deterministic order for the linker.

+  --

+  let preload1 = sort $ nonDetKeysUniqMap (filterUniqMap (isJust . uv_explicit) vis_map)

       -- add default preload units if they can be found in the db

       basicLinkedUnits = fmap (RealUnit . Definite)