module Distribution.PackageDescription.Check (
        
        PackageCheck(..),
        checkPackage,
        checkConfiguredPackage,
        
        checkPackageFiles,
        checkPackageContent,
        CheckPackageContentOps(..),
        checkPackageFileNames,
  ) where
import Distribution.Compat.Prelude
import Prelude ()
import Control.Monad                                 (mapM)
import Data.List                                     (group)
import Distribution.Compat.Lens
import Distribution.Compiler
import Distribution.License
import Distribution.Package
import Distribution.PackageDescription
import Distribution.PackageDescription.Configuration
import Distribution.Pretty                           (prettyShow)
import Distribution.Simple.BuildPaths                (autogenPathsModuleName)
import Distribution.Simple.BuildToolDepends
import Distribution.Simple.CCompiler
import Distribution.Simple.Glob
import Distribution.Simple.Utils                     hiding (findPackageDesc, notice)
import Distribution.System
import Distribution.Text
import Distribution.Types.ComponentRequestedSpec
import Distribution.Types.CondTree
import Distribution.Types.ExeDependency
import Distribution.Types.UnqualComponentName
import Distribution.Utils.Generic                    (isAscii)
import Distribution.Verbosity
import Distribution.Version
import Language.Haskell.Extension
import System.FilePath
       (splitDirectories, splitExtension, splitPath, takeExtension, takeFileName, (<.>), (</>))
import qualified Data.ByteString.Lazy      as BS
import qualified Data.Map                  as Map
import qualified Distribution.Compat.DList as DList
import qualified Distribution.SPDX         as SPDX
import qualified System.Directory          as System
import qualified System.Directory        (getDirectoryContents)
import qualified System.FilePath.Windows as FilePath.Windows (isValid)
import qualified Data.Set as Set
import qualified Distribution.Types.BuildInfo.Lens                 as L
import qualified Distribution.Types.GenericPackageDescription.Lens as L
import qualified Distribution.Types.PackageDescription.Lens        as L
data PackageCheck =
       
       
       PackageBuildImpossible { explanation :: String }
       
       
       
     | PackageBuildWarning { explanation :: String }
       
       
       
       
       
     | PackageDistSuspicious { explanation :: String }
       
       
     | PackageDistSuspiciousWarn { explanation :: String }
       
       
       
       
     | PackageDistInexcusable { explanation :: String }
  deriving (Eq, Ord)
instance Show PackageCheck where
    show notice = explanation notice
check :: Bool -> PackageCheck -> Maybe PackageCheck
check False _  = Nothing
check True  pc = Just pc
checkSpecVersion :: PackageDescription -> [Int] -> Bool -> PackageCheck
                 -> Maybe PackageCheck
checkSpecVersion pkg specver cond pc
  | specVersion pkg >= mkVersion specver  = Nothing
  | otherwise                             = check cond pc
checkPackage :: GenericPackageDescription
             -> Maybe PackageDescription
             -> [PackageCheck]
checkPackage gpkg mpkg =
     checkConfiguredPackage pkg
  ++ checkConditionals gpkg
  ++ checkPackageVersions gpkg
  ++ checkDevelopmentOnlyFlags gpkg
  ++ checkFlagNames gpkg
  ++ checkUnusedFlags gpkg
  ++ checkUnicodeXFields gpkg
  ++ checkPathsModuleExtensions pkg
  where
    pkg = fromMaybe (flattenPackageDescription gpkg) mpkg
checkConfiguredPackage :: PackageDescription -> [PackageCheck]
checkConfiguredPackage pkg =
    checkSanity pkg
 ++ checkFields pkg
 ++ checkLicense pkg
 ++ checkSourceRepos pkg
 ++ checkGhcOptions pkg
 ++ checkCCOptions pkg
 ++ checkCxxOptions pkg
 ++ checkCPPOptions pkg
 ++ checkPaths pkg
 ++ checkCabalVersion pkg
checkSanity :: PackageDescription -> [PackageCheck]
checkSanity pkg =
  catMaybes [
    check (null . unPackageName . packageName $ pkg) $
      PackageBuildImpossible "No 'name' field."
  , check (nullVersion == packageVersion pkg) $
      PackageBuildImpossible "No 'version' field."
  , check (all ($ pkg) [ null . executables
                       , null . testSuites
                       , null . benchmarks
                       , null . allLibraries
                       , null . foreignLibs ]) $
      PackageBuildImpossible
        "No executables, libraries, tests, or benchmarks found. Nothing to do."
  , check (any isNothing (map libName $ subLibraries pkg)) $
      PackageBuildImpossible $ "Found one or more unnamed internal libraries. "
        ++ "Only the non-internal library can have the same name as the package."
  , check (not (null duplicateNames)) $
      PackageBuildImpossible $ "Duplicate sections: "
        ++ commaSep (map unUnqualComponentName duplicateNames)
        ++ ". The name of every library, executable, test suite,"
        ++ " and benchmark section in"
        ++ " the package must be unique."
  
  
  , check (any (== display (packageName pkg)) (display <$> subLibNames)) $
      PackageBuildImpossible $ "Illegal internal library name "
        ++ display (packageName pkg)
        ++ ". Internal libraries cannot have the same name as the package."
        ++ " Maybe you wanted a non-internal library?"
        ++ " If so, rewrite the section stanza"
        ++ " from 'library: '" ++ display (packageName pkg) ++ "' to 'library'."
  ]
  
  --cope.
  ++ concatMap (checkLibrary    pkg) (allLibraries pkg)
  ++ concatMap (checkExecutable pkg) (executables pkg)
  ++ concatMap (checkTestSuite  pkg) (testSuites pkg)
  ++ concatMap (checkBenchmark  pkg) (benchmarks pkg)
  ++ catMaybes [
    check (specVersion pkg > cabalVersion) $
      PackageBuildImpossible $
           "This package description follows version "
        ++ display (specVersion pkg) ++ " of the Cabal specification. This "
        ++ "tool only supports up to version " ++ display cabalVersion ++ "."
  ]
  where
    
    
    
    subLibNames = catMaybes . map libName $ subLibraries pkg
    exeNames = map exeName $ executables pkg
    testNames = map testName $ testSuites pkg
    bmNames = map benchmarkName $ benchmarks pkg
    duplicateNames = dups $ subLibNames ++ exeNames ++ testNames ++ bmNames
checkLibrary :: PackageDescription -> Library -> [PackageCheck]
checkLibrary pkg lib =
  catMaybes [
    check (not (null moduleDuplicates)) $
       PackageBuildImpossible $
            "Duplicate modules in library: "
         ++ commaSep (map display moduleDuplicates)
  
  , check (null (explicitLibModules lib) && null (reexportedModules lib)) $
      PackageDistSuspiciousWarn $
           "Library " ++ (case libName lib of
                            Nothing -> ""
                            Just n -> display n
                            ) ++ "does not expose any modules"
    
  , checkVersion [1,25] (not (null (signatures lib))) $
      PackageDistInexcusable $
           "To use the 'signatures' field the package needs to specify "
        ++ "at least 'cabal-version: 2.0'."
    
  , check
      (not $ and $ map (flip elem (explicitLibModules lib)) (libModulesAutogen lib)) $
      PackageBuildImpossible $
           "An 'autogen-module' is neither on 'exposed-modules' or "
        ++ "'other-modules'."
  ]
  where
    checkVersion :: [Int] -> Bool -> PackageCheck -> Maybe PackageCheck
    checkVersion ver cond pc
      | specVersion pkg >= mkVersion ver       = Nothing
      | otherwise                              = check cond pc
    
    moduleDuplicates = dups (explicitLibModules lib ++
                             map moduleReexportName (reexportedModules lib))
checkExecutable :: PackageDescription -> Executable -> [PackageCheck]
checkExecutable pkg exe =
  catMaybes [
    check (null (modulePath exe)) $
      PackageBuildImpossible $
        "No 'main-is' field found for executable " ++ display (exeName exe)
  , check (not (null (modulePath exe))
       && (not $ fileExtensionSupportedLanguage $ modulePath exe)) $
      PackageBuildImpossible $
           "The 'main-is' field must specify a '.hs' or '.lhs' file "
        ++ "(even if it is generated by a preprocessor), "
        ++ "or it may specify a C/C++/obj-C source file."
  , checkSpecVersion pkg [1,17]
          (fileExtensionSupportedLanguage (modulePath exe)
        && takeExtension (modulePath exe) `notElem` [".hs", ".lhs"]) $
      PackageDistInexcusable $
           "The package uses a C/C++/obj-C source file for the 'main-is' field. "
        ++ "To use this feature you must specify 'cabal-version: >= 1.18'."
  , check (not (null moduleDuplicates)) $
       PackageBuildImpossible $
            "Duplicate modules in executable '" ++ display (exeName exe) ++ "': "
         ++ commaSep (map display moduleDuplicates)
    
  , check
      (not $ and $ map (flip elem (exeModules exe)) (exeModulesAutogen exe)) $
      PackageBuildImpossible $
           "On executable '" ++ display (exeName exe) ++ "' an 'autogen-module' is not "
        ++ "on 'other-modules'"
  ]
  where
    moduleDuplicates = dups (exeModules exe)
checkTestSuite :: PackageDescription -> TestSuite -> [PackageCheck]
checkTestSuite pkg test =
  catMaybes [
    case testInterface test of
      TestSuiteUnsupported tt@(TestTypeUnknown _ _) -> Just $
        PackageBuildWarning $
             quote (display tt) ++ " is not a known type of test suite. "
          ++ "The known test suite types are: "
          ++ commaSep (map display knownTestTypes)
      TestSuiteUnsupported tt -> Just $
        PackageBuildWarning $
             quote (display tt) ++ " is not a supported test suite version. "
          ++ "The known test suite types are: "
          ++ commaSep (map display knownTestTypes)
      _ -> Nothing
  , check (not $ null moduleDuplicates) $
      PackageBuildImpossible $
           "Duplicate modules in test suite '" ++ display (testName test) ++ "': "
        ++ commaSep (map display moduleDuplicates)
  , check mainIsWrongExt $
      PackageBuildImpossible $
           "The 'main-is' field must specify a '.hs' or '.lhs' file "
        ++ "(even if it is generated by a preprocessor), "
        ++ "or it may specify a C/C++/obj-C source file."
  , checkSpecVersion pkg [1,17] (mainIsNotHsExt && not mainIsWrongExt) $
      PackageDistInexcusable $
           "The package uses a C/C++/obj-C source file for the 'main-is' field. "
        ++ "To use this feature you must specify 'cabal-version: >= 1.18'."
    
  , check
      (not $ and $ map
        (flip elem (testModules test))
        (testModulesAutogen test)
      ) $
      PackageBuildImpossible $
           "On test suite '" ++ display (testName test) ++ "' an 'autogen-module' is not "
        ++ "on 'other-modules'"
  ]
  where
    moduleDuplicates = dups $ testModules test
    mainIsWrongExt = case testInterface test of
      TestSuiteExeV10 _ f -> not $ fileExtensionSupportedLanguage f
      _                   -> False
    mainIsNotHsExt = case testInterface test of
      TestSuiteExeV10 _ f -> takeExtension f `notElem` [".hs", ".lhs"]
      _                   -> False
checkBenchmark :: PackageDescription -> Benchmark -> [PackageCheck]
checkBenchmark _pkg bm =
  catMaybes [
    case benchmarkInterface bm of
      BenchmarkUnsupported tt@(BenchmarkTypeUnknown _ _) -> Just $
        PackageBuildWarning $
             quote (display tt) ++ " is not a known type of benchmark. "
          ++ "The known benchmark types are: "
          ++ commaSep (map display knownBenchmarkTypes)
      BenchmarkUnsupported tt -> Just $
        PackageBuildWarning $
             quote (display tt) ++ " is not a supported benchmark version. "
          ++ "The known benchmark types are: "
          ++ commaSep (map display knownBenchmarkTypes)
      _ -> Nothing
  , check (not $ null moduleDuplicates) $
      PackageBuildImpossible $
           "Duplicate modules in benchmark '" ++ display (benchmarkName bm) ++ "': "
        ++ commaSep (map display moduleDuplicates)
  , check mainIsWrongExt $
      PackageBuildImpossible $
           "The 'main-is' field must specify a '.hs' or '.lhs' file "
        ++ "(even if it is generated by a preprocessor)."
    
  , check
      (not $ and $ map
        (flip elem (benchmarkModules bm))
        (benchmarkModulesAutogen bm)
      ) $
      PackageBuildImpossible $
             "On benchmark '" ++ display (benchmarkName bm) ++ "' an 'autogen-module' is "
          ++ "not on 'other-modules'"
  ]
  where
    moduleDuplicates = dups $ benchmarkModules bm
    mainIsWrongExt = case benchmarkInterface bm of
      BenchmarkExeV10 _ f -> takeExtension f `notElem` [".hs", ".lhs"]
      _                   -> False
checkFields :: PackageDescription -> [PackageCheck]
checkFields pkg =
  catMaybes [
    check (not . FilePath.Windows.isValid . display . packageName $ pkg) $
      PackageDistInexcusable $
           "Unfortunately, the package name '" ++ display (packageName pkg)
        ++ "' is one of the reserved system file names on Windows. Many tools "
        ++ "need to convert package names to file names so using this name "
        ++ "would cause problems."
  , check ((isPrefixOf "z-") . display . packageName $ pkg) $
      PackageDistInexcusable $
           "Package names with the prefix 'z-' are reserved by Cabal and "
        ++ "cannot be used."
  , check (isNothing (buildTypeRaw pkg) && specVersion pkg < mkVersion [2,1]) $
      PackageBuildWarning $
           "No 'build-type' specified. If you do not need a custom Setup.hs or "
        ++ "./configure script then use 'build-type: Simple'."
  , check (isJust (setupBuildInfo pkg) && buildType pkg /= Custom) $
      PackageBuildWarning $
           "Ignoring the 'custom-setup' section because the 'build-type' is "
        ++ "not 'Custom'. Use 'build-type: Custom' if you need to use a "
        ++ "custom Setup.hs script."
  , check (not (null unknownCompilers)) $
      PackageBuildWarning $
        "Unknown compiler " ++ commaSep (map quote unknownCompilers)
                            ++ " in 'tested-with' field."
  , check (not (null unknownLanguages)) $
      PackageBuildWarning $
        "Unknown languages: " ++ commaSep unknownLanguages
  , check (not (null unknownExtensions)) $
      PackageBuildWarning $
        "Unknown extensions: " ++ commaSep unknownExtensions
  , check (not (null languagesUsedAsExtensions)) $
      PackageBuildWarning $
           "Languages listed as extensions: "
        ++ commaSep languagesUsedAsExtensions
        ++ ". Languages must be specified in either the 'default-language' "
        ++ " or the 'other-languages' field."
  , check (not (null ourDeprecatedExtensions)) $
      PackageDistSuspicious $
           "Deprecated extensions: "
        ++ commaSep (map (quote . display . fst) ourDeprecatedExtensions)
        ++ ". " ++ unwords
             [ "Instead of '" ++ display ext
            ++ "' use '" ++ display replacement ++ "'."
             | (ext, Just replacement) <- ourDeprecatedExtensions ]
  , check (null (category pkg)) $
      PackageDistSuspicious "No 'category' field."
  , check (null (maintainer pkg)) $
      PackageDistSuspicious "No 'maintainer' field."
  , check (null (synopsis pkg) && null (description pkg)) $
      PackageDistInexcusable "No 'synopsis' or 'description' field."
  , check (null (description pkg) && not (null (synopsis pkg))) $
      PackageDistSuspicious "No 'description' field."
  , check (null (synopsis pkg) && not (null (description pkg))) $
      PackageDistSuspicious "No 'synopsis' field."
    
    
    
  , check (length (synopsis pkg) >= 80) $
      PackageDistSuspicious
        "The 'synopsis' field is rather long (max 80 chars is recommended)."
    
  , check (not (null (description pkg))
           && length (description pkg) <= length (synopsis pkg)) $
      PackageDistSuspicious $
           "The 'description' field should be longer than the 'synopsis' "
        ++ "field. "
        ++ "It's useful to provide an informative 'description' to allow "
        ++ "Haskell programmers who have never heard about your package to "
        ++ "understand the purpose of your package. "
        ++ "The 'description' field content is typically shown by tooling "
        ++ "(e.g. 'cabal info', Haddock, Hackage) below the 'synopsis' which "
        ++ "serves as a headline. "
        ++ "Please refer to <https://www.haskell.org/"
        ++ "cabal/users-guide/developing-packages.html#package-properties>"
        ++ " for more details."
    
  , check (not (null testedWithImpossibleRanges)) $
      PackageDistInexcusable $
           "Invalid 'tested-with' version range: "
        ++ commaSep (map display testedWithImpossibleRanges)
        ++ ". To indicate that you have tested a package with multiple "
        ++ "different versions of the same compiler use multiple entries, "
        ++ "for example 'tested-with: GHC==6.10.4, GHC==6.12.3' and not "
        ++ "'tested-with: GHC==6.10.4 && ==6.12.3'."
  
  
  
  , check (False && not (null depInternalLibraryWithExtraVersion)) $
      PackageBuildWarning $
           "The package has an extraneous version range for a dependency on an "
        ++ "internal library: "
        ++ commaSep (map display depInternalLibraryWithExtraVersion)
        ++ ". This version range includes the current package but isn't needed "
        ++ "as the current package's library will always be used."
  , check (not (null depInternalLibraryWithImpossibleVersion)) $
      PackageBuildImpossible $
           "The package has an impossible version range for a dependency on an "
        ++ "internal library: "
        ++ commaSep (map display depInternalLibraryWithImpossibleVersion)
        ++ ". This version range does not include the current package, and must "
        ++ "be removed as the current package's library will always be used."
  , check (not (null depInternalExecutableWithExtraVersion)) $
      PackageBuildWarning $
           "The package has an extraneous version range for a dependency on an "
        ++ "internal executable: "
        ++ commaSep (map display depInternalExecutableWithExtraVersion)
        ++ ". This version range includes the current package but isn't needed "
        ++ "as the current package's executable will always be used."
  , check (not (null depInternalExecutableWithImpossibleVersion)) $
      PackageBuildImpossible $
           "The package has an impossible version range for a dependency on an "
        ++ "internal executable: "
        ++ commaSep (map display depInternalExecutableWithImpossibleVersion)
        ++ ". This version range does not include the current package, and must "
        ++ "be removed as the current package's executable will always be used."
  , check (not (null depMissingInternalExecutable)) $
      PackageBuildImpossible $
           "The package depends on a missing internal executable: "
        ++ commaSep (map display depInternalExecutableWithImpossibleVersion)
  ]
  where
    unknownCompilers  = [ name | (OtherCompiler name, _) <- testedWith pkg ]
    unknownLanguages  = [ name | bi <- allBuildInfo pkg
                               , UnknownLanguage name <- allLanguages bi ]
    unknownExtensions = [ name | bi <- allBuildInfo pkg
                               , UnknownExtension name <- allExtensions bi
                               , name `notElem` map display knownLanguages ]
    ourDeprecatedExtensions = nub $ catMaybes
      [ find ((==ext) . fst) deprecatedExtensions
      | bi <- allBuildInfo pkg
      , ext <- allExtensions bi ]
    languagesUsedAsExtensions =
      [ name | bi <- allBuildInfo pkg
             , UnknownExtension name <- allExtensions bi
             , name `elem` map display knownLanguages ]
    testedWithImpossibleRanges =
      [ Dependency (mkPackageName (display compiler)) vr
      | (compiler, vr) <- testedWith pkg
      , isNoVersion vr ]
    internalLibraries =
        map (maybe (packageName pkg) (unqualComponentNameToPackageName) . libName)
            (allLibraries pkg)
    internalExecutables = map exeName $ executables pkg
    internalLibDeps =
      [ dep
      | bi <- allBuildInfo pkg
      , dep@(Dependency name _) <- targetBuildDepends bi
      , name `elem` internalLibraries
      ]
    internalExeDeps =
      [ dep
      | bi <- allBuildInfo pkg
      , dep <- getAllToolDependencies pkg bi
      , isInternal pkg dep
      ]
    depInternalLibraryWithExtraVersion =
      [ dep
      | dep@(Dependency _ versionRange) <- internalLibDeps
      , not $ isAnyVersion versionRange
      , packageVersion pkg `withinRange` versionRange
      ]
    depInternalLibraryWithImpossibleVersion =
      [ dep
      | dep@(Dependency _ versionRange) <- internalLibDeps
      , not $ packageVersion pkg `withinRange` versionRange
      ]
    depInternalExecutableWithExtraVersion =
      [ dep
      | dep@(ExeDependency _ _ versionRange) <- internalExeDeps
      , not $ isAnyVersion versionRange
      , packageVersion pkg `withinRange` versionRange
      ]
    depInternalExecutableWithImpossibleVersion =
      [ dep
      | dep@(ExeDependency _ _ versionRange) <- internalExeDeps
      , not $ packageVersion pkg `withinRange` versionRange
      ]
    depMissingInternalExecutable =
      [ dep
      | dep@(ExeDependency _ eName _) <- internalExeDeps
      , not $ eName `elem` internalExecutables
      ]
checkLicense :: PackageDescription -> [PackageCheck]
checkLicense pkg = case licenseRaw pkg of
    Right l -> checkOldLicense pkg l
    Left  l -> checkNewLicense pkg l
checkNewLicense :: PackageDescription -> SPDX.License -> [PackageCheck]
checkNewLicense _pkg lic = catMaybes
    [ check (lic == SPDX.NONE) $
        PackageDistInexcusable
            "The 'license' field is missing or is NONE."
    ]
checkOldLicense :: PackageDescription -> License -> [PackageCheck]
checkOldLicense pkg lic = catMaybes
  [ check (lic == UnspecifiedLicense) $
      PackageDistInexcusable
        "The 'license' field is missing."
  , check (lic == AllRightsReserved) $
      PackageDistSuspicious
        "The 'license' is AllRightsReserved. Is that really what you want?"
  , checkVersion [1,4] (lic `notElem` compatLicenses) $
      PackageDistInexcusable $
           "Unfortunately the license " ++ quote (prettyShow (license pkg))
        ++ " messes up the parser in earlier Cabal versions so you need to "
        ++ "specify 'cabal-version: >= 1.4'. Alternatively if you require "
        ++ "compatibility with earlier Cabal versions then use 'OtherLicense'."
  , case lic of
      UnknownLicense l -> Just $
        PackageBuildWarning $
             quote ("license: " ++ l) ++ " is not a recognised license. The "
          ++ "known licenses are: "
          ++ commaSep (map display knownLicenses)
      _ -> Nothing
  , check (lic == BSD4) $
      PackageDistSuspicious $
           "Using 'license: BSD4' is almost always a misunderstanding. 'BSD4' "
        ++ "refers to the old 4-clause BSD license with the advertising "
        ++ "clause. 'BSD3' refers the new 3-clause BSD license."
  , case unknownLicenseVersion (lic) of
      Just knownVersions -> Just $
        PackageDistSuspicious $
             "'license: " ++ display (lic) ++ "' is not a known "
          ++ "version of that license. The known versions are "
          ++ commaSep (map display knownVersions)
          ++ ". If this is not a mistake and you think it should be a known "
          ++ "version then please file a ticket."
      _ -> Nothing
  , check (lic `notElem` [ AllRightsReserved
                                 , UnspecifiedLicense, PublicDomain]
           
           
        && null (licenseFiles pkg)) $
      PackageDistSuspicious "A 'license-file' is not specified."
  ]
  where
    unknownLicenseVersion (GPL  (Just v))
      | v `notElem` knownVersions = Just knownVersions
      where knownVersions = [ v' | GPL  (Just v') <- knownLicenses ]
    unknownLicenseVersion (LGPL (Just v))
      | v `notElem` knownVersions = Just knownVersions
      where knownVersions = [ v' | LGPL (Just v') <- knownLicenses ]
    unknownLicenseVersion (AGPL (Just v))
      | v `notElem` knownVersions = Just knownVersions
      where knownVersions = [ v' | AGPL (Just v') <- knownLicenses ]
    unknownLicenseVersion (Apache  (Just v))
      | v `notElem` knownVersions = Just knownVersions
      where knownVersions = [ v' | Apache  (Just v') <- knownLicenses ]
    unknownLicenseVersion _ = Nothing
    checkVersion :: [Int] -> Bool -> PackageCheck -> Maybe PackageCheck
    checkVersion ver cond pc
      | specVersion pkg >= mkVersion ver       = Nothing
      | otherwise                              = check cond pc
    compatLicenses = [ GPL Nothing, LGPL Nothing, AGPL Nothing, BSD3, BSD4
                     , PublicDomain, AllRightsReserved
                     , UnspecifiedLicense, OtherLicense ]
checkSourceRepos :: PackageDescription -> [PackageCheck]
checkSourceRepos pkg =
  catMaybes $ concat [[
    case repoKind repo of
      RepoKindUnknown kind -> Just $ PackageDistInexcusable $
        quote kind ++ " is not a recognised kind of source-repository. "
                   ++ "The repo kind is usually 'head' or 'this'"
      _ -> Nothing
  , check (isNothing (repoType repo)) $
      PackageDistInexcusable
        "The source-repository 'type' is a required field."
  , check (isNothing (repoLocation repo)) $
      PackageDistInexcusable
        "The source-repository 'location' is a required field."
  , check (repoType repo == Just CVS && isNothing (repoModule repo)) $
      PackageDistInexcusable
        "For a CVS source-repository, the 'module' is a required field."
  , check (repoKind repo == RepoThis && isNothing (repoTag repo)) $
      PackageDistInexcusable $
           "For the 'this' kind of source-repository, the 'tag' is a required "
        ++ "field. It should specify the tag corresponding to this version "
        ++ "or release of the package."
  , check (maybe False isAbsoluteOnAnyPlatform (repoSubdir repo)) $
      PackageDistInexcusable
        "The 'subdir' field of a source-repository must be a relative path."
  ]
  | repo <- sourceRepos pkg ]
checkGhcOptions :: PackageDescription -> [PackageCheck]
checkGhcOptions pkg =
  catMaybes [
    checkFlags ["-fasm"] $
      PackageDistInexcusable $
           "'ghc-options: -fasm' is unnecessary and will not work on CPU "
        ++ "architectures other than x86, x86-64, ppc or sparc."
  , checkFlags ["-fvia-C"] $
      PackageDistSuspicious $
           "'ghc-options: -fvia-C' is usually unnecessary. If your package "
        ++ "needs -via-C for correctness rather than performance then it "
        ++ "is using the FFI incorrectly and will probably not work with GHC "
        ++ "6.10 or later."
  , checkFlags ["-fhpc"] $
      PackageDistInexcusable $
           "'ghc-options: -fhpc' is not not necessary. Use the configure flag "
        ++ " --enable-coverage instead."
  , checkFlags ["-prof"] $
      PackageBuildWarning $
           "'ghc-options: -prof' is not necessary and will lead to problems "
        ++ "when used on a library. Use the configure flag "
        ++ "--enable-library-profiling and/or --enable-profiling."
  , checkFlags ["-o"] $
      PackageBuildWarning $
           "'ghc-options: -o' is not needed. "
        ++ "The output files are named automatically."
  , checkFlags ["-hide-package"] $
      PackageBuildWarning $
      "'ghc-options: -hide-package' is never needed. "
      ++ "Cabal hides all packages."
  , checkFlags ["--make"] $
      PackageBuildWarning $
      "'ghc-options: --make' is never needed. Cabal uses this automatically."
  , checkFlags ["-main-is"] $
      PackageDistSuspicious $
      "'ghc-options: -main-is' is not portable."
  , checkNonTestAndBenchmarkFlags ["-O0", "-Onot"] $
      PackageDistSuspicious $
      "'ghc-options: -O0' is not needed. "
      ++ "Use the --disable-optimization configure flag."
  , checkTestAndBenchmarkFlags ["-O0", "-Onot"] $
      PackageDistSuspiciousWarn $
      "'ghc-options: -O0' is not needed. "
      ++ "Use the --disable-optimization configure flag."
  , checkFlags [ "-O", "-O1"] $
      PackageDistInexcusable $
      "'ghc-options: -O' is not needed. "
      ++ "Cabal automatically adds the '-O' flag. "
      ++ "Setting it yourself interferes with the --disable-optimization flag."
  , checkFlags ["-O2"] $
      PackageDistSuspiciousWarn $
      "'ghc-options: -O2' is rarely needed. "
      ++ "Check that it is giving a real benefit "
      ++ "and not just imposing longer compile times on your users."
  , checkFlags ["-split-sections"] $
      PackageBuildWarning $
        "'ghc-options: -split-sections' is not needed. "
        ++ "Use the --enable-split-sections configure flag."
  , checkFlags ["-split-objs"] $
      PackageBuildWarning $
        "'ghc-options: -split-objs' is not needed. "
        ++ "Use the --enable-split-objs configure flag."
  , checkFlags ["-optl-Wl,-s", "-optl-s"] $
      PackageDistInexcusable $
           "'ghc-options: -optl-Wl,-s' is not needed and is not portable to all"
        ++ " operating systems. Cabal 1.4 and later automatically strip"
        ++ " executables. Cabal also has a flag --disable-executable-stripping"
        ++ " which is necessary when building packages for some Linux"
        ++ " distributions and using '-optl-Wl,-s' prevents that from working."
  , checkFlags ["-fglasgow-exts"] $
      PackageDistSuspicious $
        "Instead of 'ghc-options: -fglasgow-exts' it is preferable to use "
        ++ "the 'extensions' field."
  , check ("-threaded" `elem` lib_ghc_options) $
      PackageBuildWarning $
           "'ghc-options: -threaded' has no effect for libraries. It should "
        ++ "only be used for executables."
  , check ("-rtsopts" `elem` lib_ghc_options) $
      PackageBuildWarning $
           "'ghc-options: -rtsopts' has no effect for libraries. It should "
        ++ "only be used for executables."
  , check (any (\opt -> "-with-rtsopts" `isPrefixOf` opt) lib_ghc_options) $
      PackageBuildWarning $
           "'ghc-options: -with-rtsopts' has no effect for libraries. It "
        ++ "should only be used for executables."
  , checkAlternatives "ghc-options" "extensions"
      [ (flag, display extension) | flag <- all_ghc_options
                                  , Just extension <- [ghcExtension flag] ]
  , checkAlternatives "ghc-options" "extensions"
      [ (flag, extension) | flag@('-':'X':extension) <- all_ghc_options ]
  , checkAlternatives "ghc-options" "cpp-options" $
         [ (flag, flag) | flag@('-':'D':_) <- all_ghc_options ]
      ++ [ (flag, flag) | flag@('-':'U':_) <- all_ghc_options ]
  , checkAlternatives "ghc-options" "include-dirs"
      [ (flag, dir) | flag@('-':'I':dir) <- all_ghc_options ]
  , checkAlternatives "ghc-options" "extra-libraries"
      [ (flag, lib) | flag@('-':'l':lib) <- all_ghc_options ]
  , checkAlternatives "ghc-options" "extra-lib-dirs"
      [ (flag, dir) | flag@('-':'L':dir) <- all_ghc_options ]
  , checkAlternatives "ghc-options" "frameworks"
      [ (flag, fmwk) | (flag@"-framework", fmwk) <-
           zip all_ghc_options (safeTail all_ghc_options) ]
  , checkAlternatives "ghc-options" "extra-framework-dirs"
      [ (flag, dir) | (flag@"-framework-path", dir) <-
           zip all_ghc_options (safeTail all_ghc_options) ]
  ]
  where
    all_ghc_options    = concatMap get_ghc_options (allBuildInfo pkg)
    lib_ghc_options    = concatMap (get_ghc_options . libBuildInfo)
                         (allLibraries pkg)
    get_ghc_options bi = hcOptions GHC bi ++ hcProfOptions GHC bi
                         ++ hcSharedOptions GHC bi
    test_ghc_options      = concatMap (get_ghc_options . testBuildInfo)
                            (testSuites pkg)
    benchmark_ghc_options = concatMap (get_ghc_options . benchmarkBuildInfo)
                            (benchmarks pkg)
    test_and_benchmark_ghc_options     = test_ghc_options ++
                                         benchmark_ghc_options
    non_test_and_benchmark_ghc_options = concatMap get_ghc_options
                                         (allBuildInfo (pkg { testSuites = []
                                                            , benchmarks = []
                                                            }))
    checkFlags :: [String] -> PackageCheck -> Maybe PackageCheck
    checkFlags flags = check (any (`elem` flags) all_ghc_options)
    checkTestAndBenchmarkFlags :: [String] -> PackageCheck -> Maybe PackageCheck
    checkTestAndBenchmarkFlags flags = check (any (`elem` flags) test_and_benchmark_ghc_options)
    checkNonTestAndBenchmarkFlags :: [String] -> PackageCheck -> Maybe PackageCheck
    checkNonTestAndBenchmarkFlags flags = check (any (`elem` flags) non_test_and_benchmark_ghc_options)
    ghcExtension ('-':'f':name) = case name of
      "allow-overlapping-instances"    -> enable  OverlappingInstances
      "no-allow-overlapping-instances" -> disable OverlappingInstances
      "th"                             -> enable  TemplateHaskell
      "no-th"                          -> disable TemplateHaskell
      "ffi"                            -> enable  ForeignFunctionInterface
      "no-ffi"                         -> disable ForeignFunctionInterface
      "fi"                             -> enable  ForeignFunctionInterface
      "no-fi"                          -> disable ForeignFunctionInterface
      "monomorphism-restriction"       -> enable  MonomorphismRestriction
      "no-monomorphism-restriction"    -> disable MonomorphismRestriction
      "mono-pat-binds"                 -> enable  MonoPatBinds
      "no-mono-pat-binds"              -> disable MonoPatBinds
      "allow-undecidable-instances"    -> enable  UndecidableInstances
      "no-allow-undecidable-instances" -> disable UndecidableInstances
      "allow-incoherent-instances"     -> enable  IncoherentInstances
      "no-allow-incoherent-instances"  -> disable IncoherentInstances
      "arrows"                         -> enable  Arrows
      "no-arrows"                      -> disable Arrows
      "generics"                       -> enable  Generics
      "no-generics"                    -> disable Generics
      "implicit-prelude"               -> enable  ImplicitPrelude
      "no-implicit-prelude"            -> disable ImplicitPrelude
      "implicit-params"                -> enable  ImplicitParams
      "no-implicit-params"             -> disable ImplicitParams
      "bang-patterns"                  -> enable  BangPatterns
      "no-bang-patterns"               -> disable BangPatterns
      "scoped-type-variables"          -> enable  ScopedTypeVariables
      "no-scoped-type-variables"       -> disable ScopedTypeVariables
      "extended-default-rules"         -> enable  ExtendedDefaultRules
      "no-extended-default-rules"      -> disable ExtendedDefaultRules
      _                                -> Nothing
    ghcExtension "-cpp"             = enable CPP
    ghcExtension _                  = Nothing
    enable  e = Just (EnableExtension e)
    disable e = Just (DisableExtension e)
checkCCOptions :: PackageDescription -> [PackageCheck]
checkCCOptions = checkCLikeOptions "C" "cc-options" ccOptions
checkCxxOptions :: PackageDescription -> [PackageCheck]
checkCxxOptions = checkCLikeOptions "C++" "cxx-options" cxxOptions
checkCLikeOptions :: String -> String -> (BuildInfo -> [String]) -> PackageDescription -> [PackageCheck]
checkCLikeOptions label prefix accessor pkg =
  catMaybes [
    checkAlternatives prefix "include-dirs"
      [ (flag, dir) | flag@('-':'I':dir) <- all_cLikeOptions ]
  , checkAlternatives prefix "extra-libraries"
      [ (flag, lib) | flag@('-':'l':lib) <- all_cLikeOptions ]
  , checkAlternatives prefix "extra-lib-dirs"
      [ (flag, dir) | flag@('-':'L':dir) <- all_cLikeOptions ]
  , checkAlternatives "ld-options" "extra-libraries"
      [ (flag, lib) | flag@('-':'l':lib) <- all_ldOptions ]
  , checkAlternatives "ld-options" "extra-lib-dirs"
      [ (flag, dir) | flag@('-':'L':dir) <- all_ldOptions ]
  , checkCCFlags [ "-O", "-Os", "-O0", "-O1", "-O2", "-O3" ] $
      PackageDistSuspicious $
           "'"++prefix++": -O[n]' is generally not needed. When building with "
        ++ " optimisations Cabal automatically adds '-O2' for "++label++" code. "
        ++ "Setting it yourself interferes with the --disable-optimization flag."
  ]
  where all_cLikeOptions = [ opts | bi <- allBuildInfo pkg
                                  , opts <- accessor bi ]
        all_ldOptions = [ opts | bi <- allBuildInfo pkg
                               , opts <- ldOptions bi ]
        checkCCFlags :: [String] -> PackageCheck -> Maybe PackageCheck
        checkCCFlags flags = check (any (`elem` flags) all_cLikeOptions)
checkCPPOptions :: PackageDescription -> [PackageCheck]
checkCPPOptions pkg =
  catMaybes [
    checkAlternatives "cpp-options" "include-dirs"
      [ (flag, dir) | flag@('-':'I':dir) <- all_cppOptions]
    ]
  where all_cppOptions = [ opts | bi <- allBuildInfo pkg
                                , opts <- cppOptions bi ]
checkAlternatives :: String -> String -> [(String, String)]
                  -> Maybe PackageCheck
checkAlternatives badField goodField flags =
  check (not (null badFlags)) $
    PackageBuildWarning $
         "Instead of " ++ quote (badField ++ ": " ++ unwords badFlags)
      ++ " use " ++ quote (goodField ++ ": " ++ unwords goodFlags)
  where (badFlags, goodFlags) = unzip flags
checkPaths :: PackageDescription -> [PackageCheck]
checkPaths pkg =
  [ PackageBuildWarning $
         quote (kind ++ ": " ++ path)
      ++ " is a relative path outside of the source tree. "
      ++ "This will not work when generating a tarball with 'sdist'."
  | (path, kind) <- relPaths ++ absPaths
  , isOutsideTree path ]
  ++
  [ PackageDistInexcusable $
      quote (kind ++ ": " ++ path) ++ " is an absolute path."
  | (path, kind) <- relPaths
  , isAbsoluteOnAnyPlatform path ]
  ++
  [ PackageDistInexcusable $
         quote (kind ++ ": " ++ path) ++ " points inside the 'dist' "
      ++ "directory. This is not reliable because the location of this "
      ++ "directory is configurable by the user (or package manager). In "
      ++ "addition the layout of the 'dist' directory is subject to change "
      ++ "in future versions of Cabal."
  | (path, kind) <- relPaths ++ absPaths
  , isInsideDist path ]
  ++
  [ PackageDistInexcusable $
         "The 'ghc-options' contains the path '" ++ path ++ "' which points "
      ++ "inside the 'dist' directory. This is not reliable because the "
      ++ "location of this directory is configurable by the user (or package "
      ++ "manager). In addition the layout of the 'dist' directory is subject "
      ++ "to change in future versions of Cabal."
  | bi <- allBuildInfo pkg
  , (GHC, flags) <- options bi
  , path <- flags
  , isInsideDist path ]
  ++
  [ PackageDistInexcusable $
        "In the 'data-files' field: " ++ explainGlobSyntaxError pat err
  | pat <- dataFiles pkg
  , Left err <- [parseFileGlob (specVersion pkg) pat]
  ]
  ++
  [ PackageDistInexcusable $
        "In the 'extra-source-files' field: " ++ explainGlobSyntaxError pat err
  | pat <- extraSrcFiles pkg
  , Left err <- [parseFileGlob (specVersion pkg) pat]
  ]
  ++
  [ PackageDistInexcusable $
        "In the 'extra-doc-files' field: " ++ explainGlobSyntaxError pat err
  | pat <- extraDocFiles pkg
  , Left err <- [parseFileGlob (specVersion pkg) pat]
  ]
  where
    isOutsideTree path = case splitDirectories path of
      "..":_     -> True
      ".":"..":_ -> True
      _          -> False
    isInsideDist path = case map lowercase (splitDirectories path) of
      "dist"    :_ -> True
      ".":"dist":_ -> True
      _            -> False
    
    relPaths =
         [ (path, "extra-source-files") | path <- extraSrcFiles pkg ]
      ++ [ (path, "extra-tmp-files")    | path <- extraTmpFiles pkg ]
      ++ [ (path, "extra-doc-files")    | path <- extraDocFiles pkg ]
      ++ [ (path, "data-files")         | path <- dataFiles     pkg ]
      ++ [ (path, "data-dir")           | path <- [dataDir      pkg]]
      ++ [ (path, "license-file")       | path <- licenseFiles  pkg ]
      ++ concat
         [    [ (path, "asm-sources")      | path <- asmSources      bi ]
           ++ [ (path, "cmm-sources")      | path <- cmmSources      bi ]
           ++ [ (path, "c-sources")        | path <- cSources        bi ]
           ++ [ (path, "cxx-sources")      | path <- cxxSources      bi ]
           ++ [ (path, "js-sources")       | path <- jsSources       bi ]
           ++ [ (path, "install-includes") | path <- installIncludes bi ]
           ++ [ (path, "hs-source-dirs")   | path <- hsSourceDirs    bi ]
         | bi <- allBuildInfo pkg ]
    
    absPaths = concat
      [    [ (path, "includes")         | path <- includes        bi ]
        ++ [ (path, "include-dirs")     | path <- includeDirs     bi ]
        ++ [ (path, "extra-lib-dirs")   | path <- extraLibDirs    bi ]
      | bi <- allBuildInfo pkg ]
checkCabalVersion :: PackageDescription -> [PackageCheck]
checkCabalVersion pkg =
  catMaybes [
    
    check (specVersion pkg >= mkVersion [1,10]
           && not simpleSpecVersionRangeSyntax) $
      PackageBuildWarning $
           "Packages relying on Cabal 1.10 or later must only specify a "
        ++ "version range of the form 'cabal-version: >= x.y'. Use "
        ++ "'cabal-version: >= " ++ display (specVersion pkg) ++ "'."
    
  , check (specVersion pkg < mkVersion [1,9]
           && not simpleSpecVersionRangeSyntax) $
      PackageDistSuspicious $
           "It is recommended that the 'cabal-version' field only specify a "
        ++ "version range of the form '>= x.y'. Use "
        ++ "'cabal-version: >= " ++ display (specVersion pkg) ++ "'. "
        ++ "Tools based on Cabal 1.10 and later will ignore upper bounds."
    
  , checkVersion [1,12] simpleSpecVersionSyntax $
      PackageBuildWarning $
           "With Cabal 1.10 or earlier, the 'cabal-version' field must use "
        ++ "range syntax rather than a simple version number. Use "
        ++ "'cabal-version: >= " ++ display (specVersion pkg) ++ "'."
    
  , check (specVersion pkg >= mkVersion [1,12]
           && not simpleSpecVersionSyntax) $
      (if specVersion pkg >= mkVersion [2,0] then PackageDistSuspicious else PackageDistSuspiciousWarn) $
           "Packages relying on Cabal 1.12 or later should specify a "
        ++ "specific version of the Cabal spec of the form "
        ++ "'cabal-version: x.y'. "
        ++ "Use 'cabal-version: " ++ display (specVersion pkg) ++ "'."
    
  , checkVersion [1,8] (not (null $ testSuites pkg)) $
      PackageDistInexcusable $
           "The 'test-suite' section is new in Cabal 1.10. "
        ++ "Unfortunately it messes up the parser in older Cabal versions "
        ++ "so you must specify at least 'cabal-version: >= 1.8', but note "
        ++ "that only Cabal 1.10 and later can actually run such test suites."
    
    
    
  , checkVersion [1,10] (any isJust (buildInfoField defaultLanguage)) $
      PackageBuildWarning $
           "To use the 'default-language' field the package needs to specify "
        ++ "at least 'cabal-version: >= 1.10'."
  , check (specVersion pkg >= mkVersion [1,10]
           && (any isNothing (buildInfoField defaultLanguage))) $
      PackageBuildWarning $
           "Packages using 'cabal-version: >= 1.10' must specify the "
        ++ "'default-language' field for each component (e.g. Haskell98 or "
        ++ "Haskell2010). If a component uses different languages in "
        ++ "different modules then list the other ones in the "
        ++ "'other-languages' field."
  , checkVersion [1,18]
    (not . null $ extraDocFiles pkg) $
      PackageDistInexcusable $
           "To use the 'extra-doc-files' field the package needs to specify "
        ++ "at least 'cabal-version: >= 1.18'."
  , checkVersion [2,0]
    (not (null (subLibraries pkg))) $
      PackageDistInexcusable $
           "To use multiple 'library' sections or a named library section "
        ++ "the package needs to specify at least 'cabal-version: 2.0'."
    
  , checkVersion [1,21]
    (any (not.null.reexportedModules) (allLibraries pkg)) $
      PackageDistInexcusable $
           "To use the 'reexported-module' field the package needs to specify "
        ++ "at least 'cabal-version: >= 1.22'."
    
  , checkVersion [1,25] usesBackpackIncludes $
      PackageDistInexcusable $
           "To use the 'mixins' field the package needs to specify "
        ++ "at least 'cabal-version: 2.0'."
    
  , checkVersion [1,23] (any (not . null) (buildInfoField extraFrameworkDirs)) $
      
      PackageDistSuspiciousWarn $
           "To use the 'extra-framework-dirs' field the package needs to specify"
        ++ " at least 'cabal-version: >= 1.24'."
    
    
  , checkVersion [1,10] (any (not . null) (buildInfoField defaultExtensions)) $
      PackageBuildWarning $
           "To use the 'default-extensions' field the package needs to specify "
        ++ "at least 'cabal-version: >= 1.10'."
    
  , check (specVersion pkg >= mkVersion [1,10]
           && (any (not . null) (buildInfoField oldExtensions))) $
      PackageBuildWarning $
           "For packages using 'cabal-version: >= 1.10' the 'extensions' "
        ++ "field is deprecated. The new 'default-extensions' field lists "
        ++ "extensions that are used in all modules in the component, while "
        ++ "the 'other-extensions' field lists extensions that are used in "
        ++ "some modules, e.g. via the {-# LANGUAGE #-} pragma."
    
  , checkVersion [1,8] (not (null versionRangeExpressions)) $
      PackageDistInexcusable $
           "The package uses full version-range expressions "
        ++ "in a 'build-depends' field: "
        ++ commaSep (map displayRawDependency versionRangeExpressions)
        ++ ". To use this new syntax the package needs to specify at least "
        ++ "'cabal-version: >= 1.8'. Alternatively, if broader compatibility "
        ++ "is important, then convert to conjunctive normal form, and use "
        ++ "multiple 'build-depends:' lines, one conjunct per line."
    
  , checkVersion [1,6] (not (null depsUsingWildcardSyntax)) $
      PackageDistInexcusable $
           "The package uses wildcard syntax in the 'build-depends' field: "
        ++ commaSep (map display depsUsingWildcardSyntax)
        ++ ". To use this new syntax the package need to specify at least "
        ++ "'cabal-version: >= 1.6'. Alternatively, if broader compatibility "
        ++ "is important then use: " ++ commaSep
           [ display (Dependency name (eliminateWildcardSyntax versionRange))
           | Dependency name versionRange <- depsUsingWildcardSyntax ]
    
  , checkVersion [2,0] (not (null depsUsingMajorBoundSyntax)) $
      PackageDistInexcusable $
           "The package uses major bounded version syntax in the "
        ++ "'build-depends' field: "
        ++ commaSep (map display depsUsingMajorBoundSyntax)
        ++ ". To use this new syntax the package need to specify at least "
        ++ "'cabal-version: 2.0'. Alternatively, if broader compatibility "
        ++ "is important then use: " ++ commaSep
           [ display (Dependency name (eliminateMajorBoundSyntax versionRange))
           | Dependency name versionRange <- depsUsingMajorBoundSyntax ]
  , checkVersion [2,1] (any (not . null)
                        (concatMap buildInfoField
                         [ asmSources
                         , cmmSources
                         , extraBundledLibs
                         , extraLibFlavours ])) $
      PackageDistInexcusable $
           "The use of 'asm-sources', 'cmm-sources', 'extra-bundled-libraries' "
        ++ " and 'extra-library-flavours' requires the package "
        ++ " to specify at least 'cabal-version: >= 2.1'."
  , checkVersion [2,1] (any (not . null)
                        (buildInfoField virtualModules)) $
      PackageDistInexcusable $
           "The use of 'virtual-modules' requires the package "
        ++ " to specify at least 'cabal-version: >= 2.1'."
    
  , checkVersion [1,8] (not (null testedWithVersionRangeExpressions)) $
      PackageDistInexcusable $
           "The package uses full version-range expressions "
        ++ "in a 'tested-with' field: "
        ++ commaSep (map displayRawDependency testedWithVersionRangeExpressions)
        ++ ". To use this new syntax the package needs to specify at least "
        ++ "'cabal-version: >= 1.8'."
    
  , checkVersion [1,6] (not (null testedWithUsingWildcardSyntax)) $
      PackageDistInexcusable $
           "The package uses wildcard syntax in the 'tested-with' field: "
        ++ commaSep (map display testedWithUsingWildcardSyntax)
        ++ ". To use this new syntax the package need to specify at least "
        ++ "'cabal-version: >= 1.6'. Alternatively, if broader compatibility "
        ++ "is important then use: " ++ commaSep
           [ display (Dependency name (eliminateWildcardSyntax versionRange))
           | Dependency name versionRange <- testedWithUsingWildcardSyntax ]
    
  , checkVersion [1,6] (not (null (sourceRepos pkg))) $
      PackageDistInexcusable $
           "The 'source-repository' section is new in Cabal 1.6. "
        ++ "Unfortunately it messes up the parser in earlier Cabal versions "
        ++ "so you need to specify 'cabal-version: >= 1.6'."
    
  , checkVersion [1,2,3] (not (null mentionedExtensionsThatNeedCabal12)) $
      PackageDistInexcusable $
           "Unfortunately the language extensions "
        ++ commaSep (map (quote . display) mentionedExtensionsThatNeedCabal12)
        ++ " break the parser in earlier Cabal versions so you need to "
        ++ "specify 'cabal-version: >= 1.2.3'. Alternatively if you require "
        ++ "compatibility with earlier Cabal versions then you may be able to "
        ++ "use an equivalent compiler-specific flag."
  , checkVersion [1,4] (not (null mentionedExtensionsThatNeedCabal14)) $
      PackageDistInexcusable $
           "Unfortunately the language extensions "
        ++ commaSep (map (quote . display) mentionedExtensionsThatNeedCabal14)
        ++ " break the parser in earlier Cabal versions so you need to "
        ++ "specify 'cabal-version: >= 1.4'. Alternatively if you require "
        ++ "compatibility with earlier Cabal versions then you may be able to "
        ++ "use an equivalent compiler-specific flag."
  , check (specVersion pkg >= mkVersion [1,23]
           && isNothing (setupBuildInfo pkg)
           && buildType pkg == Custom) $
      PackageBuildWarning $
           "Packages using 'cabal-version: >= 1.24' with 'build-type: Custom' "
        ++ "must use a 'custom-setup' section with a 'setup-depends' field "
        ++ "that specifies the dependencies of the Setup.hs script itself. "
        ++ "The 'setup-depends' field uses the same syntax as 'build-depends', "
        ++ "so a simple example would be 'setup-depends: base, Cabal'."
  , check (specVersion pkg < mkVersion [1,23]
           && isNothing (setupBuildInfo pkg)
           && buildType pkg == Custom) $
      PackageDistSuspiciousWarn $
           "From version 1.24 cabal supports specifiying explicit dependencies "
        ++ "for Custom setup scripts. Consider using cabal-version >= 1.24 and "
        ++ "adding a 'custom-setup' section with a 'setup-depends' field "
        ++ "that specifies the dependencies of the Setup.hs script itself. "
        ++ "The 'setup-depends' field uses the same syntax as 'build-depends', "
        ++ "so a simple example would be 'setup-depends: base, Cabal'."
  , check (specVersion pkg >= mkVersion [1,25]
           && elem (autogenPathsModuleName pkg) allModuleNames
           && not (elem (autogenPathsModuleName pkg) allModuleNamesAutogen) ) $
      PackageDistInexcusable $
           "Packages using 'cabal-version: 2.0' and the autogenerated "
        ++ "module Paths_* must include it also on the 'autogen-modules' field "
        ++ "besides 'exposed-modules' and 'other-modules'. This specifies that "
        ++ "the module does not come with the package and is generated on "
        ++ "setup. Modules built with a custom Setup.hs script also go here "
        ++ "to ensure that commands like sdist don't fail."
  ]
  where
    
    
    
    
    checkVersion :: [Int] -> Bool -> PackageCheck -> Maybe PackageCheck
    checkVersion ver cond pc
      | specVersion pkg >= mkVersion ver       = Nothing
      | otherwise                              = check cond pc
    buildInfoField field         = map field (allBuildInfo pkg)
    versionRangeExpressions =
        [ dep | dep@(Dependency _ vr) <- allBuildDepends pkg
              , usesNewVersionRangeSyntax vr ]
    testedWithVersionRangeExpressions =
        [ Dependency (mkPackageName (display compiler)) vr
        | (compiler, vr) <- testedWith pkg
        , usesNewVersionRangeSyntax vr ]
    simpleSpecVersionRangeSyntax =
        either (const True) (cataVersionRange alg) (specVersionRaw pkg)
      where
        alg (OrLaterVersionF _) = True
        alg _                   = False
    
    simpleSpecVersionSyntax =
      either (const True) (const False) (specVersionRaw pkg)
    usesNewVersionRangeSyntax :: VersionRange -> Bool
    usesNewVersionRangeSyntax
        = (> 2) 
        . cataVersionRange alg
      where
        alg (UnionVersionRangesF a b) = a + b
        alg (IntersectVersionRangesF a b) = a + b
        alg (VersionRangeParensF _) = 3
        alg _ = 1 :: Int
    depsUsingWildcardSyntax = [ dep | dep@(Dependency _ vr) <- allBuildDepends pkg
                                    , usesWildcardSyntax vr ]
    depsUsingMajorBoundSyntax = [ dep | dep@(Dependency _ vr) <- allBuildDepends pkg
                                      , usesMajorBoundSyntax vr ]
    usesBackpackIncludes = any (not . null . mixins) (allBuildInfo pkg)
    testedWithUsingWildcardSyntax =
      [ Dependency (mkPackageName (display compiler)) vr
      | (compiler, vr) <- testedWith pkg
      , usesWildcardSyntax vr ]
    usesWildcardSyntax :: VersionRange -> Bool
    usesWildcardSyntax = cataVersionRange alg
      where
        alg (WildcardVersionF _)          = True
        alg (UnionVersionRangesF a b)     = a || b
        alg (IntersectVersionRangesF a b) = a || b
        alg (VersionRangeParensF a)       = a
        alg _                             = False
    
    
    eliminateWildcardSyntax = hyloVersionRange embed projectVersionRange
      where
        embed (WildcardVersionF v) = intersectVersionRanges
            (orLaterVersion v) (earlierVersion (wildcardUpperBound v))
        embed (MajorBoundVersionF v) = intersectVersionRanges
            (orLaterVersion v) (earlierVersion (majorUpperBound v))
        embed vr = embedVersionRange vr
    usesMajorBoundSyntax :: VersionRange -> Bool
    usesMajorBoundSyntax = cataVersionRange alg
      where
        alg (MajorBoundVersionF _)        = True
        alg (UnionVersionRangesF a b)     = a || b
        alg (IntersectVersionRangesF a b) = a || b
        alg (VersionRangeParensF a)       = a
        alg _                             = False
    eliminateMajorBoundSyntax = hyloVersionRange embed projectVersionRange
      where
        embed (MajorBoundVersionF v) = intersectVersionRanges
            (orLaterVersion v) (earlierVersion (majorUpperBound v))
        embed vr = embedVersionRange vr
    mentionedExtensions = [ ext | bi <- allBuildInfo pkg
                                , ext <- allExtensions bi ]
    mentionedExtensionsThatNeedCabal12 =
      nub (filter (`elem` compatExtensionsExtra) mentionedExtensions)
    
    
    mentionedExtensionsThatNeedCabal14 =
      nub (filter (`notElem` compatExtensions) mentionedExtensions)
    
    compatExtensions =
      map EnableExtension
      [ OverlappingInstances, UndecidableInstances, IncoherentInstances
      , RecursiveDo, ParallelListComp, MultiParamTypeClasses
      , FunctionalDependencies, Rank2Types
      , RankNTypes, PolymorphicComponents, ExistentialQuantification
      , ScopedTypeVariables, ImplicitParams, FlexibleContexts
      , FlexibleInstances, EmptyDataDecls, CPP, BangPatterns
      , TypeSynonymInstances, TemplateHaskell, ForeignFunctionInterface
      , Arrows, Generics, NamedFieldPuns, PatternGuards
      , GeneralizedNewtypeDeriving, ExtensibleRecords, RestrictedTypeSynonyms
      , HereDocuments] ++
      map DisableExtension
      [MonomorphismRestriction, ImplicitPrelude] ++
      compatExtensionsExtra
    
    
    compatExtensionsExtra =
      map EnableExtension
      [ KindSignatures, MagicHash, TypeFamilies, StandaloneDeriving
      , UnicodeSyntax, PatternSignatures, UnliftedFFITypes, LiberalTypeSynonyms
      , TypeOperators, RecordWildCards, RecordPuns, DisambiguateRecordFields
      , OverloadedStrings, GADTs, RelaxedPolyRec
      , ExtendedDefaultRules, UnboxedTuples, DeriveDataTypeable
      , ConstrainedClassMethods
      ] ++
      map DisableExtension
      [MonoPatBinds]
    allModuleNames =
         (case library pkg of
           Nothing -> []
           (Just lib) -> explicitLibModules lib
         )
      ++ concatMap otherModules (allBuildInfo pkg)
    allModuleNamesAutogen = concatMap autogenModules (allBuildInfo pkg)
displayRawDependency :: Dependency -> String
displayRawDependency (Dependency pkg vr) =
  display pkg ++ " " ++ display vr
checkPackageVersions :: GenericPackageDescription -> [PackageCheck]
checkPackageVersions pkg =
  catMaybes [
    
    
    
    
    check (not (boundedAbove baseDependency)) $
      PackageDistInexcusable $
           "The dependency 'build-depends: base' does not specify an upper "
        ++ "bound on the version number. Each major release of the 'base' "
        ++ "package changes the API in various ways and most packages will "
        ++ "need some changes to compile with it. The recommended practise "
        ++ "is to specify an upper bound on the version of the 'base' "
        ++ "package. This ensures your package will continue to build when a "
        ++ "new major version of the 'base' package is released. If you are "
        ++ "not sure what upper bound to use then use the next  major "
        ++ "version. For example if you have tested your package with 'base' "
        ++ "version 4.5 and 4.6 then use 'build-depends: base >= 4.5 && < 4.7'."
  ]
  where
    
    
    
    
    
    
    
    finalised = finalizePD
                              mempty defaultComponentRequestedSpec (const True)
                              buildPlatform
                              (unknownCompilerInfo
                                (CompilerId buildCompilerFlavor nullVersion)
                                NoAbiTag)
                              [] pkg
    baseDependency = case finalised of
      Right (pkg', _) | not (null baseDeps) ->
          foldr intersectVersionRanges anyVersion baseDeps
        where
          baseDeps =
            [ vr | Dependency pname vr <- allBuildDepends pkg'
                 , pname == mkPackageName "base" ]
      
      
      
      _          -> noVersion
    boundedAbove :: VersionRange -> Bool
    boundedAbove vr = case asVersionIntervals vr of
      []        -> True 
      intervals -> case last intervals of
        (_,   UpperBound _ _) -> True
        (_, NoUpperBound    ) -> False
checkConditionals :: GenericPackageDescription -> [PackageCheck]
checkConditionals pkg =
  catMaybes [
    check (not $ null unknownOSs) $
      PackageDistInexcusable $
           "Unknown operating system name "
        ++ commaSep (map quote unknownOSs)
  , check (not $ null unknownArches) $
      PackageDistInexcusable $
           "Unknown architecture name "
        ++ commaSep (map quote unknownArches)
  , check (not $ null unknownImpls) $
      PackageDistInexcusable $
           "Unknown compiler name "
        ++ commaSep (map quote unknownImpls)
  ]
  where
    unknownOSs    = [ os   | OS   (OtherOS os)           <- conditions ]
    unknownArches = [ arch | Arch (OtherArch arch)       <- conditions ]
    unknownImpls  = [ impl | Impl (OtherCompiler impl) _ <- conditions ]
    conditions = concatMap fvs (maybeToList (condLibrary pkg))
              ++ concatMap (fvs . snd) (condSubLibraries pkg)
              ++ concatMap (fvs . snd) (condForeignLibs pkg)
              ++ concatMap (fvs . snd) (condExecutables pkg)
              ++ concatMap (fvs . snd) (condTestSuites pkg)
              ++ concatMap (fvs . snd) (condBenchmarks pkg)
    fvs (CondNode _ _ ifs) = concatMap compfv ifs 
    compfv (CondBranch c ct mct) = condfv c ++ fvs ct ++ maybe [] fvs mct
    condfv c = case c of
      Var v      -> [v]
      Lit _      -> []
      CNot c1    -> condfv c1
      COr  c1 c2 -> condfv c1 ++ condfv c2
      CAnd c1 c2 -> condfv c1 ++ condfv c2
checkFlagNames :: GenericPackageDescription -> [PackageCheck]
checkFlagNames gpd
    | null invalidFlagNames = []
    | otherwise             = [ PackageDistInexcusable
        $ "Suspicious flag names: " ++ unwords invalidFlagNames ++ ". "
        ++ "To avoid ambiguity in command line interfaces, flag shouldn't "
        ++ "start with a dash. Also for better compatibility, flag names "
        ++ "shouldn't contain non-ascii characters."
        ]
  where
    invalidFlagNames =
        [ fn
        | flag <- genPackageFlags gpd
        , let fn = unFlagName (flagName flag)
        , invalidFlagName fn
        ]
    
    invalidFlagName ('-':_) = True
    
    invalidFlagName cs = any (not . isAscii) cs
checkUnusedFlags :: GenericPackageDescription -> [PackageCheck]
checkUnusedFlags gpd
    | declared == used = []
    | otherwise        = [ PackageDistSuspicious
        $ "Declared and used flag sets differ: "
        ++ s declared ++ " /= " ++ s used ++ ". "
        ]
  where
    s :: Set.Set FlagName -> String
    s = commaSep . map unFlagName . Set.toList
    declared :: Set.Set FlagName
    declared = toSetOf (L.genPackageFlags . traverse . L.flagName) gpd
    used :: Set.Set FlagName
    used = mconcat
        [ toSetOf (L.condLibrary      . traverse      . traverseCondTreeV . L._Flag) gpd
        , toSetOf (L.condSubLibraries . traverse . _2 . traverseCondTreeV . L._Flag) gpd
        , toSetOf (L.condForeignLibs  . traverse . _2 . traverseCondTreeV . L._Flag) gpd
        , toSetOf (L.condExecutables  . traverse . _2 . traverseCondTreeV . L._Flag) gpd
        , toSetOf (L.condTestSuites   . traverse . _2 . traverseCondTreeV . L._Flag) gpd
        , toSetOf (L.condBenchmarks   . traverse . _2 . traverseCondTreeV . L._Flag) gpd
        ]
checkUnicodeXFields :: GenericPackageDescription -> [PackageCheck]
checkUnicodeXFields gpd
    | null nonAsciiXFields = []
    | otherwise            = [ PackageDistInexcusable
        $ "Non ascii custom fields: " ++ unwords nonAsciiXFields ++ ". "
        ++ "For better compatibility, custom field names "
        ++ "shouldn't contain non-ascii characters."
        ]
  where
    nonAsciiXFields :: [String]
    nonAsciiXFields = [ n | (n, _) <- xfields, any (not . isAscii) n ]
    xfields :: [(String,String)]
    xfields = DList.runDList $ mconcat
        [ toDListOf (L.packageDescription . L.customFieldsPD . traverse) gpd
        , toDListOf (L.traverseBuildInfos . L.customFieldsBI . traverse) gpd
        ]
checkPathsModuleExtensions :: PackageDescription -> [PackageCheck]
checkPathsModuleExtensions pd
    | specVersion pd >= mkVersion [2,1] = []
    | any checkBI (allBuildInfo pd) || any checkLib (allLibraries pd)
        = return $ PackageBuildImpossible $ unwords
            [ "The package uses RebindableSyntax with OverloadedStrings or OverloadedLists"
            , "in default-extensions, and also Paths_ autogen module."
            , "That configuration is known to cause compile failures with Cabal < 2.2."
            , "To use these default-extensions with Paths_ autogen module"
            , "specify at least 'cabal-version: 2.2'."
            ]
    | otherwise = []
  where
    mn = autogenPathsModuleName pd
    checkLib :: Library -> Bool
    checkLib l = mn `elem` exposedModules l && checkExts (l ^. L.defaultExtensions)
    checkBI :: BuildInfo -> Bool
    checkBI bi =
        (mn `elem` otherModules bi || mn `elem` autogenModules bi) &&
        checkExts (bi ^. L.defaultExtensions)
    checkExts exts = rebind `elem` exts && (strings `elem` exts || lists `elem` exts)
      where
        rebind  = EnableExtension RebindableSyntax
        strings = EnableExtension OverloadedStrings
        lists   = EnableExtension OverloadedLists
checkDevelopmentOnlyFlagsBuildInfo :: BuildInfo -> [PackageCheck]
checkDevelopmentOnlyFlagsBuildInfo bi =
  catMaybes [
    check has_WerrorWall $
      PackageDistInexcusable $
           "'ghc-options: -Wall -Werror' makes the package very easy to "
        ++ "break with future GHC versions because new GHC versions often "
        ++ "add new warnings. Use just 'ghc-options: -Wall' instead."
        ++ extraExplanation
  , check (not has_WerrorWall && has_Werror) $
      PackageDistInexcusable $
           "'ghc-options: -Werror' makes the package easy to "
        ++ "break with future GHC versions because new GHC versions often "
        ++ "add new warnings. "
        ++ extraExplanation
  , check (has_J) $
      PackageDistInexcusable $
           "'ghc-options: -j[N]' can make sense for specific user's setup,"
        ++ " but it is not appropriate for a distributed package."
        ++ extraExplanation
  , checkFlags ["-fdefer-type-errors"] $
      PackageDistInexcusable $
           "'ghc-options: -fdefer-type-errors' is fine during development but "
        ++ "is not appropriate for a distributed package. "
        ++ extraExplanation
    
  , check (any (\opt -> "-d" `isPrefixOf` opt && opt /= "-dynamic")
           ghc_options) $
      PackageDistInexcusable $
           "'ghc-options: -d*' debug flags are not appropriate "
        ++ "for a distributed package. "
        ++ extraExplanation
  , checkFlags ["-fprof-auto", "-fprof-auto-top", "-fprof-auto-calls",
               "-fprof-cafs", "-fno-prof-count-entries",
               "-auto-all", "-auto", "-caf-all"] $
      PackageDistSuspicious $
           "'ghc-options/ghc-prof-options: -fprof*' profiling flags are typically not "
        ++ "appropriate for a distributed library package. These flags are "
        ++ "useful to profile this package, but when profiling other packages "
        ++ "that use this one these flags clutter the profile output with "
        ++ "excessive detail. If you think other packages really want to see "
        ++ "cost centres from this package then use '-fprof-auto-exported' "
        ++ "which puts cost centres only on exported functions. "
        ++ extraExplanation
  ]
  where
    extraExplanation =
         " Alternatively, if you want to use this, make it conditional based "
      ++ "on a Cabal configuration flag (with 'manual: True' and 'default: "
      ++ "False') and enable that flag during development."
    has_WerrorWall   = has_Werror && ( has_Wall || has_W )
    has_Werror       = "-Werror" `elem` ghc_options
    has_Wall         = "-Wall"   `elem` ghc_options
    has_W            = "-W"      `elem` ghc_options
    has_J            = any
                         (\o -> case o of
                           "-j"                -> True
                           ('-' : 'j' : d : _) -> isDigit d
                           _                   -> False
                         )
                         ghc_options
    ghc_options      = hcOptions GHC bi ++ hcProfOptions GHC bi
                       ++ hcSharedOptions GHC bi
    checkFlags :: [String] -> PackageCheck -> Maybe PackageCheck
    checkFlags flags = check (any (`elem` flags) ghc_options)
checkDevelopmentOnlyFlags :: GenericPackageDescription -> [PackageCheck]
checkDevelopmentOnlyFlags pkg =
    concatMap checkDevelopmentOnlyFlagsBuildInfo
              [ bi
              | (conditions, bi) <- allConditionalBuildInfo
              , not (any guardedByManualFlag conditions) ]
  where
    guardedByManualFlag = definitelyFalse
    
    
    definitelyFalse (Var (Flag n)) = maybe False not (Map.lookup n manualFlags)
    definitelyFalse (Var _)        = False
    definitelyFalse (Lit  b)       = not b
    definitelyFalse (CNot c)       = definitelyTrue c
    definitelyFalse (COr  c1 c2)   = definitelyFalse c1 && definitelyFalse c2
    definitelyFalse (CAnd c1 c2)   = definitelyFalse c1 || definitelyFalse c2
    definitelyTrue (Var (Flag n)) = fromMaybe False (Map.lookup n manualFlags)
    definitelyTrue (Var _)        = False
    definitelyTrue (Lit  b)       = b
    definitelyTrue (CNot c)       = definitelyFalse c
    definitelyTrue (COr  c1 c2)   = definitelyTrue c1 || definitelyTrue c2
    definitelyTrue (CAnd c1 c2)   = definitelyTrue c1 && definitelyTrue c2
    manualFlags = Map.fromList
                    [ (flagName flag, flagDefault flag)
                    | flag <- genPackageFlags pkg
                    , flagManual flag ]
    allConditionalBuildInfo :: [([Condition ConfVar], BuildInfo)]
    allConditionalBuildInfo =
        concatMap (collectCondTreePaths libBuildInfo)
                  (maybeToList (condLibrary pkg))
     ++ concatMap (collectCondTreePaths libBuildInfo . snd)
                  (condSubLibraries pkg)
     ++ concatMap (collectCondTreePaths buildInfo . snd)
                  (condExecutables pkg)
     ++ concatMap (collectCondTreePaths testBuildInfo . snd)
                  (condTestSuites pkg)
     ++ concatMap (collectCondTreePaths benchmarkBuildInfo . snd)
                  (condBenchmarks pkg)
    
    
    collectCondTreePaths :: (a -> b)
                         -> CondTree v c a
                         -> [([Condition v], b)]
    collectCondTreePaths mapData = go []
      where
        go conditions condNode =
            
            (reverse conditions, mapData (condTreeData condNode))
          : concat
            [ go (condition:conditions) ifThen
            | (CondBranch condition ifThen _) <- condTreeComponents condNode ]
         ++ concat
            [ go (condition:conditions) elseThen
            | (CondBranch condition _ (Just elseThen)) <- condTreeComponents condNode ]
checkPackageFiles :: Verbosity -> PackageDescription -> FilePath -> NoCallStackIO [PackageCheck]
checkPackageFiles verbosity pkg root = do
  contentChecks <- checkPackageContent checkFilesIO pkg
  preDistributionChecks <- checkPackageFilesPreDistribution verbosity pkg root
  
  
  
  return (sort contentChecks ++ sort preDistributionChecks)
  where
    checkFilesIO = CheckPackageContentOps {
      doesFileExist        = System.doesFileExist                  . relative,
      doesDirectoryExist   = System.doesDirectoryExist             . relative,
      getDirectoryContents = System.Directory.getDirectoryContents . relative,
      getFileContents      = BS.readFile                           . relative
    }
    relative path = root </> path
data CheckPackageContentOps m = CheckPackageContentOps {
    doesFileExist        :: FilePath -> m Bool,
    doesDirectoryExist   :: FilePath -> m Bool,
    getDirectoryContents :: FilePath -> m [FilePath],
    getFileContents      :: FilePath -> m BS.ByteString
  }
checkPackageContent :: Monad m => CheckPackageContentOps m
                    -> PackageDescription
                    -> m [PackageCheck]
checkPackageContent ops pkg = do
  cabalBomError   <- checkCabalFileBOM    ops
  cabalNameError  <- checkCabalFileName   ops pkg
  licenseErrors   <- checkLicensesExist   ops pkg
  setupError      <- checkSetupExists     ops pkg
  configureError  <- checkConfigureExists ops pkg
  localPathErrors <- checkLocalPathsExist ops pkg
  vcsLocation     <- checkMissingVcsInfo  ops pkg
  return $ licenseErrors
        ++ catMaybes [cabalBomError, cabalNameError, setupError, configureError]
        ++ localPathErrors
        ++ vcsLocation
checkCabalFileBOM :: Monad m => CheckPackageContentOps m
                  -> m (Maybe PackageCheck)
checkCabalFileBOM ops = do
  epdfile <- findPackageDesc ops
  case epdfile of
    
    
    
    
    
    
    Left _       -> return $ Nothing
    Right pdfile -> (flip check pc . BS.isPrefixOf bomUtf8)
                    `liftM` (getFileContents ops pdfile)
      where pc = PackageDistInexcusable $
                 pdfile ++ " starts with an Unicode byte order mark (BOM)."
                 ++ " This may cause problems with older cabal versions."
  where
    bomUtf8 :: BS.ByteString
    bomUtf8 = BS.pack [0xef,0xbb,0xbf] 
checkCabalFileName :: Monad m => CheckPackageContentOps m
                 -> PackageDescription
                 -> m (Maybe PackageCheck)
checkCabalFileName ops pkg = do
  
  
  
  epdfile <- findPackageDesc ops
  case epdfile of
    
    Left _       -> return Nothing
    Right pdfile
      | takeFileName pdfile == expectedCabalname -> return Nothing
      | otherwise -> return $ Just $ PackageDistInexcusable $
                 "The filename " ++ pdfile ++ " does not match package name " ++
                 "(expected: " ++ expectedCabalname ++ ")"
  where
    pkgname = unPackageName . packageName $ pkg
    expectedCabalname = pkgname <.> "cabal"
findPackageDesc :: Monad m => CheckPackageContentOps m
                 -> m (Either PackageCheck FilePath) 
findPackageDesc ops
 = do let dir = "."
      files <- getDirectoryContents ops dir
      
      
      cabalFiles <- filterM (doesFileExist ops)
                       [ dir </> file
                       | file <- files
                       , let (name, ext) = splitExtension file
                       , not (null name) && ext == ".cabal" ]
      case cabalFiles of
        []          -> return (Left $ PackageBuildImpossible noDesc)
        [cabalFile] -> return (Right cabalFile)
        multiple    -> return (Left $ PackageBuildImpossible
                               $ multiDesc multiple)
  where
    noDesc :: String
    noDesc = "No cabal file found.\n"
             ++ "Please create a package description file <pkgname>.cabal"
    multiDesc :: [String] -> String
    multiDesc l = "Multiple cabal files found while checking.\n"
                  ++ "Please use only one of: "
                  ++ intercalate ", " l
checkLicensesExist :: Monad m => CheckPackageContentOps m
                   -> PackageDescription
                   -> m [PackageCheck]
checkLicensesExist ops pkg = do
    exists <- mapM (doesFileExist ops) (licenseFiles pkg)
    return
      [ PackageBuildWarning $
           "The '" ++ fieldname ++ "' field refers to the file "
        ++ quote file ++ " which does not exist."
      | (file, False) <- zip (licenseFiles pkg) exists ]
  where
    fieldname | length (licenseFiles pkg) == 1 = "license-file"
              | otherwise                      = "license-files"
checkSetupExists :: Monad m => CheckPackageContentOps m
                 -> PackageDescription
                 -> m (Maybe PackageCheck)
checkSetupExists ops pkg = do
  let simpleBuild = buildType pkg == Simple
  hsexists  <- doesFileExist ops "Setup.hs"
  lhsexists <- doesFileExist ops "Setup.lhs"
  return $ check (not simpleBuild && not hsexists && not lhsexists) $
    PackageDistInexcusable $
      "The package is missing a Setup.hs or Setup.lhs script."
checkConfigureExists :: Monad m => CheckPackageContentOps m
                     -> PackageDescription
                     -> m (Maybe PackageCheck)
checkConfigureExists ops pd
  | buildType pd == Configure = do
      exists <- doesFileExist ops "configure"
      return $ check (not exists) $
        PackageBuildWarning $
          "The 'build-type' is 'Configure' but there is no 'configure' script. "
          ++ "You probably need to run 'autoreconf -i' to generate it."
  | otherwise = return Nothing
checkLocalPathsExist :: Monad m => CheckPackageContentOps m
                     -> PackageDescription
                     -> m [PackageCheck]
checkLocalPathsExist ops pkg = do
  let dirs = [ (dir, kind)
             | bi <- allBuildInfo pkg
             , (dir, kind) <-
                  [ (dir, "extra-lib-dirs") | dir <- extraLibDirs bi ]
               ++ [ (dir, "extra-framework-dirs")
                  | dir <- extraFrameworkDirs  bi ]
               ++ [ (dir, "include-dirs")   | dir <- includeDirs  bi ]
               ++ [ (dir, "hs-source-dirs") | dir <- hsSourceDirs bi ]
             , isRelativeOnAnyPlatform dir ]
  missing <- filterM (liftM not . doesDirectoryExist ops . fst) dirs
  return [ PackageBuildWarning {
             explanation = quote (kind ++ ": " ++ dir)
                        ++ " directory does not exist."
           }
         | (dir, kind) <- missing ]
checkMissingVcsInfo :: Monad m => CheckPackageContentOps m
                    -> PackageDescription
                    -> m [PackageCheck]
checkMissingVcsInfo ops pkg | null (sourceRepos pkg) = do
    vcsInUse <- liftM or $ mapM (doesDirectoryExist ops) repoDirnames
    if vcsInUse
      then return [ PackageDistSuspicious message ]
      else return []
  where
    repoDirnames = [ dirname | repo    <- knownRepoTypes
                             , dirname <- repoTypeDirname repo ]
    message  = "When distributing packages it is encouraged to specify source "
            ++ "control information in the .cabal file using one or more "
            ++ "'source-repository' sections. See the Cabal user guide for "
            ++ "details."
checkMissingVcsInfo _ _ = return []
repoTypeDirname :: RepoType -> [FilePath]
repoTypeDirname Darcs      = ["_darcs"]
repoTypeDirname Git        = [".git"]
repoTypeDirname SVN        = [".svn"]
repoTypeDirname CVS        = ["CVS"]
repoTypeDirname Mercurial  = [".hg"]
repoTypeDirname GnuArch    = [".arch-params"]
repoTypeDirname Bazaar     = [".bzr"]
repoTypeDirname Monotone   = ["_MTN"]
repoTypeDirname _          = []
checkPackageFileNames :: [FilePath] -> [PackageCheck]
checkPackageFileNames files =
     (take 1 . mapMaybe checkWindowsPath $ files)
  ++ (take 1 . mapMaybe checkTarPath     $ files)
      
      
checkWindowsPath :: FilePath -> Maybe PackageCheck
checkWindowsPath path =
  check (not $ FilePath.Windows.isValid path') $
    PackageDistInexcusable $
         "Unfortunately, the file " ++ quote path ++ " is not a valid file "
      ++ "name on Windows which would cause portability problems for this "
      ++ "package. Windows file names cannot contain any of the characters "
      ++ "\":*?<>|\" and there are a few reserved names including \"aux\", "
      ++ "\"nul\", \"con\", \"prn\", \"com1-9\", \"lpt1-9\" and \"clock$\"."
  where
    path' = ".\\" ++ path
    
    
checkTarPath :: FilePath -> Maybe PackageCheck
checkTarPath path
  | length path > 255   = Just longPath
  | otherwise = case pack nameMax (reverse (splitPath path)) of
    Left err           -> Just err
    Right []           -> Nothing
    Right (h:rest) -> case pack prefixMax remainder of
      Left err         -> Just err
      Right []         -> Nothing
      Right (_:_)      -> Just noSplit
     where
        
        remainder = init h : rest
  where
    nameMax, prefixMax :: Int
    nameMax   = 100
    prefixMax = 155
    pack _   []     = Left emptyName
    pack maxLen (c:cs)
      | n > maxLen  = Left longName
      | otherwise   = Right (pack' maxLen n cs)
      where n = length c
    pack' maxLen n (c:cs)
      | n' <= maxLen = pack' maxLen n' cs
      where n' = n + length c
    pack' _     _ cs = cs
    longPath = PackageDistInexcusable $
         "The following file name is too long to store in a portable POSIX "
      ++ "format tar archive. The maximum length is 255 ASCII characters.\n"
      ++ "The file in question is:\n  " ++ path
    longName = PackageDistInexcusable $
         "The following file name is too long to store in a portable POSIX "
      ++ "format tar archive. The maximum length for the name part (including "
      ++ "extension) is 100 ASCII characters. The maximum length for any "
      ++ "individual directory component is 155.\n"
      ++ "The file in question is:\n  " ++ path
    noSplit = PackageDistInexcusable $
         "The following file name is too long to store in a portable POSIX "
      ++ "format tar archive. While the total length is less than 255 ASCII "
      ++ "characters, there are unfortunately further restrictions. It has to "
      ++ "be possible to split the file path on a directory separator into "
      ++ "two parts such that the first part fits in 155 characters or less "
      ++ "and the second part fits in 100 characters or less. Basically you "
      ++ "have to make the file name or directory names shorter, or you could "
      ++ "split a long directory name into nested subdirectories with shorter "
      ++ "names.\nThe file in question is:\n  " ++ path
    emptyName = PackageDistInexcusable $
         "Encountered a file with an empty name, something is very wrong! "
      ++ "Files with an empty name cannot be stored in a tar archive or in "
      ++ "standard file systems."
checkPackageFilesPreDistribution :: Verbosity -> PackageDescription -> FilePath -> NoCallStackIO [PackageCheck]
checkPackageFilesPreDistribution = checkGlobFiles
checkGlobFiles :: Verbosity
               -> PackageDescription
               -> FilePath
               -> NoCallStackIO [PackageCheck]
checkGlobFiles verbosity pkg root =
  fmap concat $ for allGlobs $ \(field, dir, glob) ->
    
    case parseFileGlob (specVersion pkg) glob of
      Left _ -> return []
      Right parsedGlob -> do
        results <- runDirFileGlob verbosity (root </> dir) parsedGlob
        let individualWarnings = results >>= getWarning field glob
            noMatchesWarning =
              [ PackageDistSuspiciousWarn $
                     "In '" ++ field ++ "': the pattern '" ++ glob ++ "' does not"
                  ++ " match any files."
              | all (not . suppressesNoMatchesWarning) results
              ]
        return (noMatchesWarning ++ individualWarnings)
  where
    adjustedDataDir = if null (dataDir pkg) then "." else dataDir pkg
    allGlobs = concat
      [ (,,) "extra-source-files" "." <$> extraSrcFiles pkg
      , (,,) "extra-doc-files" "." <$> extraDocFiles pkg
      , (,,) "data-files" adjustedDataDir <$> dataFiles pkg
      ]
    
    
    
    
    suppressesNoMatchesWarning (GlobMatch _) = True
    suppressesNoMatchesWarning (GlobWarnMultiDot _) = False
    suppressesNoMatchesWarning (GlobMissingDirectory _) = True
    getWarning :: String -> FilePath -> GlobResult FilePath -> [PackageCheck]
    getWarning _ _ (GlobMatch _) =
      []
    
    
    
    
    getWarning field glob (GlobWarnMultiDot file) =
      [ PackageDistSuspiciousWarn $
             "In '" ++ field ++ "': the pattern '" ++ glob ++ "' does not"
          ++ " match the file '" ++ file ++ "' because the extensions do not"
          ++ " exactly match (e.g., foo.en.html does not exactly match *.html)."
          ++ " To enable looser suffix-only matching, set 'cabal-version: 2.4' or higher."
      ]
    getWarning field glob (GlobMissingDirectory dir) =
      [ PackageDistSuspiciousWarn $
             "In '" ++ field ++ "': the pattern '" ++ glob ++ "' attempts to"
          ++ " match files in the directory '" ++ dir ++ "', but there is no"
          ++ " directory by that name."
      ]
quote :: String -> String
quote s = "'" ++ s ++ "'"
commaSep :: [String] -> String
commaSep = intercalate ", "
dups :: Ord a => [a] -> [a]
dups xs = [ x | (x:_:_) <- group (sort xs) ]
fileExtensionSupportedLanguage :: FilePath -> Bool
fileExtensionSupportedLanguage path =
    isHaskell || isC
  where
    extension = takeExtension path
    isHaskell = extension `elem` [".hs", ".lhs"]
    isC       = isJust (filenameCDialect extension)