Knock the pre-distribution checks down to just warnings

Cabal/Distribution/PackageDescription/Check.hs

@@ -2157,6 +2157,9 @@ checkTarPath path
 -- and package-creation environment. Hence we can use IO, rather than needing
 -- to pass a 'CheckPackageContentOps' dictionary around.
 checkPackageFilesPreDistribution :: Verbosity -> PackageDescription -> FilePath -> NoCallStackIO [PackageCheck]
+-- Note: this really shouldn't return any 'Inexcusable' warnings,
+-- because that will make us say that Hackage would reject the package.
+-- But, because Hackage doesn't run these tests, that will be a lie!
 checkPackageFilesPreDistribution = checkGlobFiles
 
 -- | Discover problems with the package's wildcards.
@@ -2169,7 +2172,7 @@ checkGlobFiles verbosity pkg root =
     results <- matchDirFileGlob' verbosity (specVersion pkg) (root </> dir) glob
     let individualWarnings = results >>= getWarning field glob
         noMatchesWarning =
-          [ PackageDistInexcusable $
+          [ PackageDistSuspiciousWarn $
                  "In '" ++ field ++ "': the pattern '" ++ glob ++ "' does not"
               ++ " match any files."
           | all (not . suppressesNoMatchesWarning) results
@@ -2206,7 +2209,7 @@ checkGlobFiles verbosity pkg root =
           ++ " To enable looser suffix-only matching, set 'cabal-version: 2.4' or higher."
       ]
     getWarning field glob (GlobMissingDirectory dir) =
-      [ PackageDistInexcusable $
+      [ PackageDistSuspiciousWarn $
              "In '" ++ field ++ "': the pattern '" ++ glob ++ "' attempts to"
           ++ " match files in the directory '" ++ dir ++ "', but there is no"
           ++ " directory by that name."

cabal-testsuite/PackageTests/Check/MissingGlobDirectory/cabal.out

 # cabal check
 Warning: The package will not build sanely due to these errors:
 Warning: This package description follows version 2.4 of the Cabal specification. This tool only supports up to version 2.3.0.0.
-Warning: The following errors will cause portability problems on other environments:
+Warning: These warnings may cause trouble when distributing the package:
 Warning: In 'data-files': the pattern 'another-non-existent-directory/**/*.dat' attempts to match files in the directory 'another-non-existent-directory', but there is no directory by that name.
 Warning: In 'extra-doc-files': the pattern 'non-existent-directory/*.html' attempts to match files in the directory 'non-existent-directory', but there is no directory by that name.
 Warning: In 'extra-doc-files': the pattern 'present/present/missing/*.tex' attempts to match files in the directory 'present/present/missing', but there is no directory by that name.

cabal-testsuite/PackageTests/Check/MissingGlobDirectory2/cabal.out

 # cabal check
-Warning: The following errors will cause portability problems on other environments:
+Warning: These warnings may cause trouble when distributing the package:
 Warning: In 'data-files': the pattern 'non-existent-directory/*.dat' attempts to match files in the directory 'non-existent-directory', but there is no directory by that name.
-Warning: Hackage would reject this package.

cabal-testsuite/PackageTests/Check/MissingGlobDirectory2/cabal.test.hs

 import Test.Cabal.Prelude
-main = cabalTest $
-  fails $ cabal "check" []
+main = cabalTest $ cabal "check" []

cabal-testsuite/PackageTests/Check/NoGlobMatches/cabal.out

 # cabal check
-Warning: The following errors will cause portability problems on other environments:
+Warning: These warnings may cause trouble when distributing the package:
 Warning: In 'extra-doc-files': the pattern '*.html' does not match any files.
-Warning: Hackage would reject this package.

cabal-testsuite/PackageTests/Check/NoGlobMatches/cabal.test.hs

 import Test.Cabal.Prelude
-main = cabalTest $
-  fails $ cabal "check" []
+main = cabalTest $ cabal "check" []