Look for transitive setup dependency on Cabal when choosing Cabal spec version.

cabal-install/Distribution/Client/ProjectPlanning.hs

@@ -1210,7 +1210,7 @@ elaborateInstallPlan verbosity platform compiler compilerprogdb pkgConfigDB
             if null not_per_component_reasons
                 then return comps
                 else do checkPerPackageOk comps not_per_component_reasons
-                        return [elaborateSolverToPackage mapDep spkg g $
+                        return [elaborateSolverToPackage spkg g $
                                 comps ++ maybeToList setupComponent]
            Left cns ->
             dieProgress $
@@ -1276,7 +1276,7 @@ elaborateInstallPlan verbosity platform compiler compilerprogdb pkgConfigDB
                         fsep (punctuate comma reasons)
             -- TODO: Maybe exclude Backpack too
 
-        elab0 = elaborateSolverToCommon mapDep spkg
+        elab0 = elaborateSolverToCommon spkg
         pkgid = elabPkgSourceId    elab0
         pd    = elabPkgDescription elab0
 
@@ -1501,13 +1501,11 @@ elaborateInstallPlan verbosity platform compiler compilerprogdb pkgConfigDB
                                 Just (Just n) -> display n
                                 _ -> ""
 
-    elaborateSolverToPackage :: (SolverId -> [ElaboratedPlanPackage])
-                             -> SolverPackage UnresolvedPkgLoc
+    elaborateSolverToPackage :: SolverPackage UnresolvedPkgLoc
                              -> ComponentsGraph
                              -> [ElaboratedConfiguredPackage]
                              -> ElaboratedConfiguredPackage
     elaborateSolverToPackage
-        mapDep
         pkg@(SolverPackage (SourcePackage pkgid _gdesc _srcloc _descOverride)
                            _flags _stanzas _deps0 _exe_deps0)
         compGraph comps =
@@ -1516,7 +1514,7 @@ elaborateInstallPlan verbosity platform compiler compilerprogdb pkgConfigDB
         -- of the other fields of the elaboratedPackage.
         elab
       where
-        elab0@ElaboratedConfiguredPackage{..} = elaborateSolverToCommon mapDep pkg
+        elab0@ElaboratedConfiguredPackage{..} = elaborateSolverToCommon pkg
         elab = elab0 {
                 elabUnitId = newSimpleUnitId pkgInstalledId,
                 elabComponentId = pkgInstalledId,
@@ -1613,10 +1611,9 @@ elaborateInstallPlan verbosity platform compiler compilerprogdb pkgConfigDB
               (compilerId compiler)
               pkgInstalledId
 
-    elaborateSolverToCommon :: (SolverId -> [ElaboratedPlanPackage])
-                            -> SolverPackage UnresolvedPkgLoc
+    elaborateSolverToCommon :: SolverPackage UnresolvedPkgLoc
                             -> ElaboratedConfiguredPackage
-    elaborateSolverToCommon mapDep
+    elaborateSolverToCommon
         pkg@(SolverPackage (SourcePackage pkgid gdesc srcloc descOverride)
                            flags stanzas deps0 _exe_deps0) =
         elaboratedPackage
@@ -1687,10 +1684,9 @@ elaborateInstallPlan verbosity platform compiler compilerprogdb pkgConfigDB
         elabRegisterPackageDBStack = buildAndRegisterDbs
 
         elabSetupScriptStyle       = packageSetupScriptStyle elabPkgDescription
-        -- Computing the deps here is a little awful
-        deps = fmap (concatMap (elaborateLibSolverId mapDep)) deps0
-        elabSetupScriptCliVersion  = packageSetupScriptSpecVersion
-                                      elabSetupScriptStyle elabPkgDescription deps
+        elabSetupScriptCliVersion  =
+          packageSetupScriptSpecVersion
+          elabSetupScriptStyle elabPkgDescription libDepGraph deps0
         elabSetupPackageDBStack    = buildAndRegisterDbs
 
         buildAndRegisterDbs
@@ -2910,31 +2906,34 @@ defaultSetupDeps compiler platform pkg =
 -- of what the solver picked for us, based on the explicit setup deps or the
 -- ones added implicitly by 'defaultSetupDeps'.
 --
-packageSetupScriptSpecVersion :: Package pkg
-                              => SetupScriptStyle
+packageSetupScriptSpecVersion :: SetupScriptStyle
                               -> PD.PackageDescription
-                              -> ComponentDeps [pkg]
+                              -> Graph.Graph NonSetupLibDepSolverPlanPackage
+                              -> ComponentDeps [SolverId]
                               -> Version
 
 -- We're going to be using the internal Cabal library, so the spec version of
 -- that is simply the version of the Cabal library that cabal-install has been
 -- built with.
-packageSetupScriptSpecVersion SetupNonCustomInternalLib _ _ =
+packageSetupScriptSpecVersion SetupNonCustomInternalLib _ _ _ =
     cabalVersion
 
 -- If we happen to be building the Cabal lib itself then because that
 -- bootstraps itself then we use the version of the lib we're building.
-packageSetupScriptSpecVersion SetupCustomImplicitDeps pkg _
+packageSetupScriptSpecVersion SetupCustomImplicitDeps pkg _ _
   | packageName pkg == cabalPkgname
   = packageVersion pkg
 
 -- In all other cases we have a look at what version of the Cabal lib the
 -- solver picked. Or if it didn't depend on Cabal at all (which is very rare)
 -- then we look at the .cabal file to see what spec version it declares.
-packageSetupScriptSpecVersion _ pkg deps =
-    case find ((cabalPkgname ==) . packageName) (CD.setupDeps deps) of
+packageSetupScriptSpecVersion _ pkg libDepGraph deps =
+    case find ((cabalPkgname ==) . packageName) setupLibDeps of
       Just dep -> packageVersion dep
       Nothing  -> PD.specVersion pkg
+  where
+    setupLibDeps = map packageId $ fromMaybe [] $
+                   Graph.closure libDepGraph (CD.setupDeps deps)
 
 
 cabalPkgname, basePkgname :: PackageName

cabal-testsuite/PackageTests/NewBuild/T4288/CustomIssue.hs

@@ -0,0 +1,3 @@
+module CustomIssue where
+
+f x = x + 1

cabal-testsuite/PackageTests/NewBuild/T4288/Setup.hs

@@ -0,0 +1,3 @@
+import SetupHelper (setupHelperDefaultMain)
+
+main = setupHelperDefaultMain

cabal-testsuite/PackageTests/NewBuild/T4288/T4288.cabal

@@ -0,0 +1,16 @@
+name: T4288
+version: 1.0
+build-type: Custom
+
+-- cabal-version is lower than the version of Cabal that will be chosen for the
+-- setup script.
+cabal-version: >=1.10
+
+-- Setup script only has a transitive dependency on Cabal.
+custom-setup
+  setup-depends: base, setup-helper
+
+library
+  exposed-modules: CustomIssue
+  build-depends: base
+  default-language: Haskell2010

cabal-testsuite/PackageTests/NewBuild/T4288/cabal.project

@@ -0,0 +1 @@
+packages: . setup-helper/

cabal-testsuite/PackageTests/NewBuild/T4288/cabal.test.hs

@@ -0,0 +1,17 @@
+import Test.Cabal.Prelude
+
+-- This test is similar to the simplified example in issue #4288. The package's
+-- setup script only depends on base and setup-helper. setup-helper exposes a
+-- function that is a wrapper for Cabal's defaultMain (similar to
+-- cabal-doctest). This test builds the package to check that the flags passed
+-- to the setup script are compatible with the version of Cabal that it depends
+-- on, even though Cabal is only a transitive dependency.
+main = cabalTest $ do
+  skipUnless =<< hasNewBuildCompatBootCabal
+  r <- recordMode DoNotRecord $ cabal' "new-build" ["T4288"]
+  assertOutputContains "This is setup-helper-1.0." r
+  assertOutputContains
+      ("In order, the following will be built: "
+       ++ " - setup-helper-1.0 (lib:setup-helper) (first run) "
+       ++ " - T4288-1.0 (lib:T4288) (first run)")
+      r

cabal-testsuite/PackageTests/NewBuild/T4288/setup-helper/SetupHelper.hs

@@ -0,0 +1,5 @@
+module SetupHelper (setupHelperDefaultMain) where
+
+import Distribution.Simple
+
+setupHelperDefaultMain = putStrLn "This is setup-helper-1.0." >> defaultMain

cabal-testsuite/PackageTests/NewBuild/T4288/setup-helper/setup-helper.cabal

@@ -0,0 +1,9 @@
+name: setup-helper
+version: 1.0
+build-type: Simple
+cabal-version: >= 1.2
+
+library
+  exposed-modules: SetupHelper
+  build-depends: base, Cabal
+  default-language: Haskell2010