Add a regression test for issue #4288.

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

+module CustomIssue where
+
+f x = x + 1

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

+import SetupHelper (setupHelperDefaultMain)
+
+main = setupHelperDefaultMain

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

+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

+packages: . setup-helper/

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

+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

+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

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