hpc: Don't cover non-dependency libraries

We were passing the flag --coverage-for for every library in the package
when building the testsuites.

However, if a particular testsuite doesn't depend on one of the packages
passed with --coverage-for we would crash.

Since we look for the unit ids of all packages given in --coverage-for in the
package database (to find hpc artifacts), if the testsuite builds before
the library this lookup would fail.

The fix is easy: don't pass --coverage-for=<lib> to <testsuite> if
<testsuite> doesn't depend on <lib>. If <lib> is an indirect dependency
of <testsuite> it'll no longer be covered by HPC, but this is a weird
behaviour that I doubt anyone relies on.

Fixes #10046

Cabal/src/Distribution/Simple/Configure.hs

@@ -1280,7 +1280,9 @@ configureComponents
           extraCoverageUnitIds = case enabled of
             -- Whole package configure, add package libs
             ComponentRequestedSpec{} -> mapMaybe mbCompUnitId buildComponents
-            -- Component configure, no need to do anything
+            -- Component configure, no need to do anything since
+            -- extra-coverage-for will be passed for all other components that
+            -- should be covered.
             OneComponentRequestedSpec{} -> []
           mbCompUnitId LibComponentLocalBuildInfo{componentUnitId} = Just componentUnitId
           mbCompUnitId _ = Nothing

cabal-install-solver/src/Distribution/Solver/Modular/Tree.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE DeriveFunctor, DeriveFoldable, DeriveTraversable #-}
+{-# OPTIONS_GHC -ddump-to-file -ddump-simpl -ddump-stg-final #-}
 module Distribution.Solver.Modular.Tree
     ( POption(..)
     , Tree(..)

cabal-install/src/Distribution/Client/ProjectPlanning.hs

@@ -4058,7 +4058,7 @@ setupHsConfigureFlags
             Just _ -> error "non-library dependency"
             Nothing -> LMainLibName
 
-      configCoverageFor = determineCoverageFor elabPkgSourceId plan
+      configCoverageFor = determineCoverageFor elab plan
 
 setupHsConfigureArgs
   :: ElaboratedConfiguredPackage
@@ -4469,13 +4469,14 @@ inplaceBinRoot layout config package =
 
 -- The list of non-pre-existing libraries without module holes, i.e. the
 -- main library and sub-libraries components of all the local packages in
--- the project that do not require instantiations or are instantiations.
+-- the project that are dependencies of the components being built and that do
+-- not require instantiations or are instantiations.
 determineCoverageFor
-  :: PackageId
-  -- ^ The 'PackageId' of the package or component being configured
+  :: ElaboratedConfiguredPackage
+  -- ^ The package or component being configured
   -> ElaboratedInstallPlan
   -> Flag [UnitId]
-determineCoverageFor configuredPkgSourceId plan =
+determineCoverageFor configuredPkg plan =
   Flag
     $ mapMaybe
       ( \case
@@ -4488,15 +4489,18 @@ determineCoverageFor configuredPkgSourceId plan =
     $ Graph.toList
     $ InstallPlan.toGraph plan
   where
-    shouldCoverPkg elab@ElaboratedConfiguredPackage{elabModuleShape, elabPkgSourceId, elabLocalToProject} =
+    libDeps = elabLibDependencies configuredPkg
+    shouldCoverPkg elab@ElaboratedConfiguredPackage{elabModuleShape, elabPkgSourceId = pkgSID, elabLocalToProject} =
       elabLocalToProject
         && not (isIndefiniteOrInstantiation elabModuleShape)
         -- TODO(#9493): We can only cover libraries in the same package
         -- as the testsuite
-        && configuredPkgSourceId == elabPkgSourceId
+        && elabPkgSourceId configuredPkg == pkgSID
         -- Libraries only! We don't cover testsuite modules, so we never need
         -- the paths to their mix dirs. Furthermore, we do not install testsuites...
         && maybe False (\case CLibName{} -> True; CNotLibName{} -> False) (elabComponentName elab)
+        -- We only want coverage for libraries which are dependencies of the given one
+        && pkgSID `elem` map (confSrcId . fst) libDeps
 
     isIndefiniteOrInstantiation :: ModuleShape -> Bool
     isIndefiniteOrInstantiation = not . Set.null . modShapeRequires

cabal-testsuite/PackageTests/Regression/T10046/aa.cabal

@@ -0,0 +1,28 @@
+cabal-version:      3.0
+name:               aa
+version:            0.1.0.0
+license:            NONE
+build-type:         Simple
+extra-doc-files:    CHANGELOG.md
+
+library
+    exposed-modules:  MyLib
+    build-depends:    base, template-haskell
+    hs-source-dirs:   src
+    default-language: Haskell2010
+
+test-suite bb-test
+    default-language: Haskell2010
+    type:             exitcode-stdio-1.0
+    hs-source-dirs:   testbb
+    main-is:          Main.hs
+    build-depends:
+        base, aa
+
+test-suite aa-test
+    default-language: Haskell2010
+    type:             exitcode-stdio-1.0
+    hs-source-dirs:   test
+    main-is:          Main.hs
+    build-depends:
+        base

cabal-testsuite/PackageTests/Regression/T10046/app/Main.hs

@@ -0,0 +1 @@
+main = pure ()

cabal-testsuite/PackageTests/Regression/T10046/cabal.project

@@ -0,0 +1 @@
+packages: .

cabal-testsuite/PackageTests/Regression/T10046/cabal.test.hs

@@ -0,0 +1,6 @@
+import Test.Cabal.Prelude
+
+-- T10046
+main = cabalTest $ recordMode DoNotRecord $ do
+  out <- cabal' "test" ["all"]
+  assertOutputDoesNotContain "Failed to find the installed unit 'aa-0.1.0.0-inplace'" out

cabal-testsuite/PackageTests/Regression/T10046/src/MyLib.hs

@@ -0,0 +1,11 @@
+{-# LANGUAGE TemplateHaskell #-}
+module MyLib where
+
+import Control.Concurrent
+import Language.Haskell.TH
+
+-- Must take longer to compile than the testsuite
+$(do runIO $
+       threadDelay (5*1000*1000) -- 5s
+     [d| data X |]
+  )

cabal-testsuite/PackageTests/Regression/T10046/test/Main.hs

@@ -0,0 +1 @@
+main = pure ()

cabal-testsuite/PackageTests/Regression/T10046/testbb/Main.hs

@@ -0,0 +1 @@
+main = pure ()