hlint-3.8: src/Hint/Restrict.hs
{-# LANGUAGE ImportQualifiedPost #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ViewPatterns #-}
module Hint.Restrict(restrictHint) where
{-
-- These tests rely on the .hlint.yaml file in the root
<TEST>
foo = unsafePerformIO --
foo = bar `unsafePerformIO` baz --
module Util where otherFunc = unsafePerformIO $ print 1 --
module Util where exitMessageImpure = System.IO.Unsafe.unsafePerformIO $ print 1
foo = unsafePerformOI
import Data.List.NonEmpty as NE \
foo = NE.nub (NE.fromList [1, 2, 3]) --
import Hypothetical.Module \
foo = nub s
</TEST>
-}
import Hint.Type(ModuHint,ModuleEx(..),Idea(..),Severity(..),warn,rawIdea,modComments,firstDeclComments)
import Config.Type
import Util
import Data.Generics.Uniplate.DataOnly
import Data.List.NonEmpty qualified as NonEmpty
import Data.Set qualified as Set
import Data.Map qualified as Map
import Data.List.Extra
import Data.List.NonEmpty (nonEmpty)
import Data.Either
import Data.Maybe
import Data.Monoid
import Data.Semigroup
import Data.Tuple.Extra
import Control.Applicative
import Control.Monad
import Control.Monad.Extra
import Prelude
import GHC.Hs
import GHC.Types.Name.Reader
import GHC.Types.SrcLoc
import GHC.Types.Name.Occurrence
import Language.Haskell.GhclibParserEx.GHC.Hs
import Language.Haskell.GhclibParserEx.GHC.Types.Name.Reader
import GHC.Util
-- FIXME: The settings should be partially applied, but that's hard to orchestrate right now
restrictHint :: [Setting] -> ModuHint
restrictHint settings scope m =
-- Comments appearing without an empty line before the first
-- declaration in a module are now associated with the declaration
-- not the module so to be safe, look also at `firstDeclComments
-- modu`
-- (https://gitlab.haskell.org/ghc/ghc/-/merge_requests/9517).
let annsMod = modComments m
annsFirstDecl = firstDeclComments m
ps = pragmas annsMod ++ pragmas annsFirstDecl
opts = flags ps
exts = languagePragmas ps in
checkPragmas modu opts exts rOthers ++
maybe [] (checkImports modu $ hsmodImports (unLoc (ghcModule m))) (Map.lookup RestrictModule rOthers) ++
checkFunctions scope modu (hsmodDecls (unLoc (ghcModule m))) rFunction
where
modu = modName (ghcModule m)
(rFunction, rOthers) = restrictions settings
---------------------------------------------------------------------
-- UTILITIES
data RestrictItem = RestrictItem
{riAs :: [String]
,riAsRequired :: Alt Maybe Bool
,riImportStyle :: Alt Maybe RestrictImportStyle
,riQualifiedStyle :: Alt Maybe QualifiedStyle
,riWithin :: [(String, String)]
,riRestrictIdents :: RestrictIdents
,riMessage :: Maybe String
}
instance Semigroup RestrictItem where
RestrictItem x1 x2 x3 x4 x5 x6 x7
<> RestrictItem y1 y2 y3 y4 y5 y6 y7
= RestrictItem (x1<>y1) (x2<>y2) (x3<>y3) (x4<>y4) (x5<>y5) (x6<>y6) (x7<>y7)
-- Contains a map from module (Nothing if the rule is unqualified) to (within, message), so that we can
-- distinguish functions with the same name.
-- For example, this allows us to have separate rules for "Data.Map.fromList" and "Data.Set.fromList".
-- Using newtype rather than type because we want to define (<>) as 'Map.unionWith (<>)'.
newtype RestrictFunction = RestrictFun (Map.Map (Maybe String) ([(String, String)], Maybe String))
instance Semigroup RestrictFunction where
RestrictFun m1 <> RestrictFun m2 = RestrictFun (Map.unionWith (<>) m1 m2)
type RestrictFunctions = (Bool, Map.Map String RestrictFunction)
type OtherRestrictItems = Map.Map RestrictType (Bool, Map.Map String RestrictItem)
restrictions :: [Setting] -> (RestrictFunctions, OtherRestrictItems)
restrictions settings = (rFunction, rOthers)
where
(map snd -> rfs, ros) = partition ((== RestrictFunction) . fst) [(restrictType x, x) | SettingRestrict x <- settings]
rFunction = (all restrictDefault rfs, Map.fromListWith (<>) [mkRf s r | r <- rfs, s <- restrictName r])
mkRf s Restrict{..} = (name, RestrictFun $ Map.singleton modu (restrictWithin, restrictMessage))
where
-- Parse module and name from s. module = Nothing if the rule is unqualified.
(modu, name) = first (fmap NonEmpty.init . NonEmpty.nonEmpty) (breakEnd (== '.') s)
rOthers = Map.map f $ Map.fromListWith (++) (map (second pure) ros)
f rs = (all restrictDefault rs
,Map.fromListWith (<>)
[(,) s RestrictItem
{ riAs = restrictAs
, riAsRequired = restrictAsRequired
, riImportStyle = restrictImportStyle
, riQualifiedStyle = restrictQualifiedStyle
, riWithin = restrictWithin
, riRestrictIdents = restrictIdents
, riMessage = restrictMessage
}
| Restrict{..} <- rs, s <- restrictName])
ideaMessage :: Maybe String -> Idea -> Idea
ideaMessage (Just message) w = w{ideaNote=[Note message]}
ideaMessage Nothing w = w{ideaNote=[noteMayBreak]}
ideaNoTo :: Idea -> Idea
ideaNoTo w = w{ideaTo=Nothing}
noteMayBreak :: Note
noteMayBreak = Note "may break the code"
within :: String -> String -> [(String, String)] -> Bool
within modu func = any (\(a,b) -> (a ~= modu || a == "") && (b ~= func || b == ""))
where (~=) = wildcardMatch
---------------------------------------------------------------------
-- CHECKS
checkPragmas :: String
-> [(LEpaComment, [String])]
-> [(LEpaComment, [String])]
-> Map.Map RestrictType (Bool, Map.Map String RestrictItem)
-> [Idea]
checkPragmas modu flags exts mps =
f RestrictFlag "flags" flags ++ f RestrictExtension "extensions" exts
where
f tag name xs =
[(if null good then ideaNoTo else id) $ notes $ rawIdea Hint.Type.Warning ("Avoid restricted " ++ name) (getAncLoc l) c Nothing [] []
| Just (def, mp) <- [Map.lookup tag mps]
, (l@(L _ (EpaComment (EpaBlockComment c) _)), les) <- xs
, let (good, bad) = partition (isGood def mp) les
, let note = maybe noteMayBreak Note . (=<<) riMessage . flip Map.lookup mp
, let notes w = w {ideaNote=note <$> bad}
, not $ null bad]
isGood def mp x = maybe def (within modu "" . riWithin) $ Map.lookup x mp
-- | Extension to GHC's 'ImportDeclQualifiedStyle', expressing @qualifiedStyle: unrestricted@,
-- i.e. the preference of "either pre- or post-, but qualified" in a rule.
data QualifiedPostOrPre = QualifiedPostOrPre deriving Eq
checkImports :: String -> [LImportDecl GhcPs] -> (Bool, Map.Map String RestrictItem) -> [Idea]
checkImports modu lImportDecls (def, mp) = mapMaybe getImportHint lImportDecls
where
getImportHint :: LImportDecl GhcPs -> Maybe Idea
getImportHint i@(L _ ImportDecl{..}) = do
let RestrictItem{..} = getRestrictItem def ideclName mp
either (Just . ideaMessage riMessage) (const Nothing) $ do
unless (within modu "" riWithin) $
Left $ ideaNoTo $ warn "Avoid restricted module" (reLoc i) (reLoc i) []
let importedIdents = Set.fromList $
case first (== EverythingBut) <$> ideclImportList of
Just (False, lxs) -> concatMap (importListToIdents . unLoc) (unLoc lxs)
_ -> []
invalidIdents = case riRestrictIdents of
NoRestrictIdents -> Set.empty
ForbidIdents badIdents -> importedIdents `Set.intersection` Set.fromList badIdents
OnlyIdents onlyIdents -> importedIdents `Set.difference` Set.fromList onlyIdents
unless (Set.null invalidIdents) $
Left $ ideaNoTo $ warn "Avoid restricted identifiers" (reLoc i) (reLoc i) []
let qualAllowed = case (riAs, ideclAs) of
([], _) -> True
(_, Nothing) -> maybe True not $ getAlt riAsRequired
(_, Just (L _ modName)) -> moduleNameString modName `elem` riAs
unless qualAllowed $ do
let i' = noLoc $ (unLoc i){ ideclAs = noLocA . mkModuleName <$> listToMaybe riAs }
Left $ warn "Avoid restricted alias" (reLoc i) i' []
let (expectedQual, expectedHiding) =
case fromMaybe ImportStyleUnrestricted $ getAlt riImportStyle of
ImportStyleUnrestricted
| NotQualified <- ideclQualified -> (Nothing, Nothing)
| otherwise -> (Just $ second (<> " or unqualified") expectedQualStyle, Nothing)
ImportStyleQualified -> (Just expectedQualStyle, Nothing)
ImportStyleExplicitOrQualified
| Just (False, _) <- first (== EverythingBut) <$> ideclImportList -> (Nothing, Nothing)
| otherwise ->
( Just $ second (<> " or with an explicit import list") expectedQualStyle
, Nothing )
ImportStyleExplicit
| Just (False, _) <- first (== EverythingBut) <$> ideclImportList -> (Nothing, Nothing)
| otherwise ->
( Just (Right NotQualified, "unqualified")
, Just $ Just (Exactly, noLocA []) )
ImportStyleUnqualified -> (Just (Right NotQualified, "unqualified"), Nothing)
expectedQualStyle =
case fromMaybe QualifiedStyleUnrestricted $ getAlt riQualifiedStyle of
QualifiedStyleUnrestricted -> (Left QualifiedPostOrPre, "qualified")
QualifiedStylePost -> (Right QualifiedPost, "post-qualified")
QualifiedStylePre -> (Right QualifiedPre, "pre-qualified")
-- unless expectedQual is Nothing, it holds the Idea (hint) to ultimately emit,
-- except in these cases when the rule's requirements are fulfilled in-source:
qualIdea
-- the rule demands a particular importStyle, and the decl obeys exactly
| Just (Right ideclQualified) == (fst <$> expectedQual) = Nothing
-- the rule demands a QualifiedPostOrPre import, and the decl does either
| Just (Left QualifiedPostOrPre) == (fst <$> expectedQual)
&& ideclQualified `elem` [QualifiedPost, QualifiedPre] = Nothing
-- otherwise, expectedQual gets converted into a warning below (or is Nothing)
| otherwise = expectedQual
whenJust qualIdea $ \(qual, hint) -> do
-- convert non-Nothing qualIdea into hlint's refactoring Idea
let i' = noLoc $ (unLoc i){ ideclQualified = fromRight QualifiedPre qual
, ideclImportList = fromMaybe ideclImportList expectedHiding }
msg = moduleNameString (unLoc ideclName) <> " should be imported " <> hint
Left $ warn msg (reLoc i) i' []
getRestrictItem :: Bool -> LocatedA ModuleName -> Map.Map String RestrictItem -> RestrictItem
getRestrictItem def ideclName =
fromMaybe (RestrictItem mempty mempty mempty mempty [("","") | def] NoRestrictIdents Nothing)
. lookupRestrictItem ideclName
lookupRestrictItem :: LocatedA ModuleName -> Map.Map String RestrictItem -> Maybe RestrictItem
lookupRestrictItem ideclName mp =
let moduleName = moduleNameString $ unLoc ideclName
exact = Map.lookup moduleName mp
wildcard = nonEmpty
. fmap snd
. reverse -- the hope is less specific matches will end up last, but it's not guaranteed
. filter (liftA2 (&&) (elem '*') (`wildcardMatch` moduleName) . fst)
$ Map.toList mp
in exact <> sconcat (sequence wildcard)
importListToIdents :: IE GhcPs -> [String]
importListToIdents =
catMaybes .
\case (IEVar _ n) -> [fromName n]
(IEThingAbs _ n) -> [fromName n]
(IEThingAll _ n) -> [fromName n]
(IEThingWith _ n _ ns) -> fromName n : map fromName ns
_ -> []
where
fromName :: LIEWrappedName GhcPs -> Maybe String
fromName wrapped =
case unLoc wrapped of
IEName _ n -> fromId (unLoc n)
IEPattern _ n -> ("pattern " ++) <$> fromId (unLoc n)
IEType _ n -> ("type " ++) <$> fromId (unLoc n)
fromId :: IdP GhcPs -> Maybe String
fromId (Unqual n) = Just $ occNameString n
fromId (Qual _ n) = Just $ occNameString n
fromId (Orig _ n) = Just $ occNameString n
fromId (Exact _) = Nothing
checkFunctions :: Scope -> String -> [LHsDecl GhcPs] -> RestrictFunctions -> [Idea]
checkFunctions scope modu decls (def, mp) =
[ (ideaMessage message $ ideaNoTo $ warn "Avoid restricted function" (reLocN x) (reLocN x) []){ideaDecl = [dname]}
| d <- decls
, let dname = fromMaybe "" (declName d)
, x <- universeBi d :: [LocatedN RdrName]
, let xMods = possModules scope x
, let (withins, message) = fromMaybe ([("","") | def], Nothing) (findFunction mp x xMods)
, not $ within modu dname withins
]
-- Returns Just iff there are rules for x, which are either unqualified, or qualified with a module that is
-- one of x's possible modules.
-- If there are multiple matching rules (e.g., there's both an unqualified version and a qualified version), their
-- withins and messages are concatenated with (<>).
findFunction
:: Map.Map String RestrictFunction
-> LocatedN RdrName
-> [ModuleName]
-> Maybe ([(String, String)], Maybe String)
findFunction restrictMap (rdrNameStr -> x) (map moduleNameString -> possMods) = do
(RestrictFun mp) <- Map.lookup x restrictMap
n <- NonEmpty.nonEmpty . Map.elems $ Map.filterWithKey (const . maybe True (`elem` possMods)) mp
pure (sconcat n)