Inspection tests fail if -O0 is forced

[Bodigrim]

Hackage builder for some reason enforces -O0, which causes inspection tests to fail:

$ cabal run test:tests --ghc-options='-O0' -- --hide-successes
All
  Properties
    folds-unfolds
      folds
        _S_foldl'_from_foldlM' ==~ _S_foldl':                              FAIL
          LHS:
              _S_foldl'_from_foldlM'
                = ... \ (f :: a -> Char -> a) (x :: a) ->
                        . runIdentity
                          (foldlM'
                             $fMonadIdentity
                             ((\ (i :: a) (c :: Char) -> f i c) `cast` <Co:9> :: ...)
                             x)
          RHS: _S_foldl' = ... inline foldl'
          Use -p '/_S_foldl'\''_from_foldlM'\'' ==~ _S_foldl'\''/' to rerun this test only.
    lowlevel
      misc
        t_literal_foo
          mentions none of Char, List:                                     FAIL
            t_literal_foo :: Text
            t_literal_foo = pack lvl_sNbt

            lvl_sNbs :: Addr#
            lvl_sNbs = "foo"#

            lvl_sNbt :: [Char]
            lvl_sNbt = unpackCString# lvl_sNbs

            Use -p '/mentions none of Char, List/' to rerun this test only.
          uses none of pack, unstream, map, safe, streamList:              FAIL
            t_literal_foo :: Text
            t_literal_foo = pack lvl_sNbt

            lvl_sNbs :: Addr#
            lvl_sNbs = "foo"#

            lvl_sNbt :: [Char]
            lvl_sNbt = unpackCString# lvl_sNbs

            Use -p '/uses none of pack, unstream, map, safe, streamList/' to rerun this test only.
          uses none of unpackCString#, unpackCStringUtf8#:                 FAIL
            t_literal_foo :: Text
            t_literal_foo = pack lvl_sNbt

            lvl_sNbs :: Addr#
            lvl_sNbs = "foo"#

            lvl_sNbt :: [Char]
            lvl_sNbt = unpackCString# lvl_sNbs

            Use -p '/uses none of unpackCString#, unpackCStringUtf8#/' to rerun this test only.

...which is kinda expected, but annoying.

In the wild: https://hackage.haskell.org/package/text-2.1.2/reports/2

[Lysxia]

Is there a way to detect that -O0 was used and disable the tests if so?

[Bodigrim]

The test itself forces -O1:

text/tests/Tests/Properties/LowLevel.hs

Lines 9 to 12 in 1994b13

	#ifdef MIN_VERSION_tasty_inspection_testing
	{-# LANGUAGE TemplateHaskell #-}
	{-# OPTIONS_GHC -O -dsuppress-all -dno-suppress-type-signatures -fplugin=Test.Tasty.Inspection.Plugin #-}
	#endif

The problem is that the library was built with -O0, so whatever optimizations are enabled in tests they do not have access to optimized implementations of required functions.

There are probably a few ways to solve this (such as force -O1 in required library modules, or set -fexpose-all-unfoldings), although neither solution feels robust enough. After all, maybe having a "failed tests" on Hackage is not that big deal. Also I don't know why Hackage wants to run tests with -O0.

[Lysxia]

One idea is to create a cabal flag specifically for enabling inspection tests and setting -O in the library.

[Bodigrim]

One way would be to put the following definition into, say, Data.Text.Internal.Private:

isLibraryBuiltWithOptimizationsEnabled = False 
{-# RULE "are optimizations on?" isLibraryBuiltWithOptimizationsEnabled = True #-}

and then check the value of isLibraryBuiltWithOptimizationsEnabled in the test suite. Dunno, is it too evil?