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Hannes Siebenhandl pushed to branch wip/fendor/27834 at Glasgow Haskell Compiler / GHC

Commits:

665b4608

by Hannes Siebenhandl at 2026-09-30T11:10:44+02:00

Extend the `TrustOverlay` for wired-in units

The TrustOverlay only contained the `UnitId` of all on-disk units.
However, wired-in units are referred to by their wired-in unit id, which
is not the same as the on-disk unit id.

Thus, trust checks for wired-in units failed because the lookup was
using the wired-in unit, which wasn't present in the `TrustOverlay`.

We fix #27834, by copying the trust info for wired-in unit ids.

6 changed files:

changelog.d/unit-index
compiler/GHC/Unit/State.hs
+ testsuite/tests/ghci/scripts/T27834.hs
+ testsuite/tests/ghci/scripts/T27834.script
+ testsuite/tests/ghci/scripts/T27834.stdout
testsuite/tests/ghci/scripts/all.T

Changes:

changelog.d/unit-index

  section: compiler
  synopsis: Use global ``UnitIndex`` to deduplicate ``UnitInfo``s over multiple home units
 -issues: #27500 #26423 #27748
 -mrs: !16115 !16598
 +issues: #27500 #26423 #27748 #27834
 +mrs: !16115 !16598 !16743
  description: {
      The ``UnitState`` used to be duplicated for all ``HomeUnitEnv``, not sharing any of the ``UnitInfo``s.

compiler/GHC/Unit/State.hs

@@ -286,6 +286,21 @@ trustUnits elements (TrustOverlay to) = TrustOverlay $ foldl' (\ acc uid -> addT
  emptyTrustOverlay :: TrustOverlay
  emptyTrustOverlay = TrustOverlay emptyUniqMap
 +-- | For all values in the 'WireMap', copy the recorded trust/distrust
 +-- for the wired-in unit id.
 +--
 +extendForWireMap :: TrustOverlay -> WireMap -> TrustOverlay
 +extendForWireMap to wmap =
 +  foldl' go to (listWireMap wmap)
 +  where
 +    go overlay (onDiskUid, wiredInUid) =
 +      case lookupTrustOverlay overlay onDiskUid of
 +        Nothing -> overlay
 +        Just Trusted ->
 +          trustUnits [wiredInUid] overlay
 +        Just Distrusted ->
 +          distrustUnits [wiredInUid] overlay
++
  {-
  Note [Sharing 'UnitInfo's across the 'UnitEnv']
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -957,7 +972,7 @@ mkUnitState logger unit_index cfg = do
           , explicitUnits                = explicit_pkgs
           , homeUnitDepends              = home_unit_deps
           , unitInfoMap                  = pkg_db
 -         , trustedUnits                 = trustUnitsOverlay
 +         , trustedUnits                 = trustUnitsOverlay `extendForWireMap` wired_map
           , moduleNameProvidersMap       = mod_map
           , pluginModuleNameProvidersMap = mkModuleNameProvidersMap logger (unitConfigAllowVirtual cfg) pkg_db plugin_vis_map
           , packageNameMap               = pkgname_map

testsuite/tests/ghci/scripts/T27834.hs

 +{-# LANGUAGE Haskell2010 #-}
 +{-# LANGUAGE Safe #-}
 +module Main where
++
 +-- Importing a wired-in in module should honour trustworthiness
 +import GHC.Internal.Char (chr)
++
 +main :: IO ()
 +main = print (chr 120)

testsuite/tests/ghci/scripts/T27834.script

	1	+:load T27834
	2	+putStrLn "Can import trusted module from ghc-internal"

testsuite/tests/ghci/scripts/T27834.stdout

+Can import trusted module from ghc-internal

testsuite/tests/ghci/scripts/all.T

@@ -402,3 +402,4 @@ test('GhciPackageRename',
       ghci_script,
       ['GhciPackageRename.script'])
  test('T26233', normal, ghci_script, ['T26233.script'])
 +test('T27834', [extra_hc_opts("-fpackage-trust -trust base -trust ghc-internal -package ghc-internal")], ghci_script, ['T27834.script'])