Error on duplicate imports

Author: philderbeast

cabal-install-solver/src/Distribution/Solver/Types/ProjectConfigPath.hs

@@ -12,6 +12,7 @@ module Distribution.Solver.Types.ProjectConfigPath
     -- * Messages
     , docProjectConfigPath
     , cyclicalImportMsg
+    , duplicateImportMsg
     , docProjectConfigPathFailReason
 
     -- * Checks and Normalization
@@ -72,6 +73,15 @@ cyclicalImportMsg path@(ProjectConfigPath (duplicate :| _)) =
     , nest 2 (docProjectConfigPath path)
     ]
 
+-- | A message for a duplicate import.
+duplicateImportMsg :: FilePath -> ProjectConfigPath -> [(FilePath, ProjectConfigPath)] -> Doc
+duplicateImportMsg duplicate path dupImportsBy =
+    vcat
+    [ text "duplicate import of" <+> text duplicate <> semi
+    , nest 2 (docProjectConfigPath path)
+    , nest 2 (vcat [docProjectConfigPath dib | (_, dib) <- dupImportsBy])
+    ]
+
 docProjectConfigPathFailReason :: VR -> ProjectConfigPath -> Doc
 docProjectConfigPathFailReason vr pcp
     | ProjectConfigPath (p :| []) <- pcp =

cabal-install/src/Distribution/Client/ProjectConfig/Legacy.hs

@@ -1,6 +1,7 @@
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE MultiWayIf #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -33,6 +34,7 @@ module Distribution.Client.ProjectConfig.Legacy
   ) where
 
 import Data.Coerce (coerce)
+import Data.IORef
 import Distribution.Client.Compat.Prelude
 
 import Distribution.Types.Flag (FlagName, parsecFlagAssignment)
@@ -245,41 +247,51 @@ parseProject
 parseProject rootPath cacheDir httpTransport verbosity configToParse = do
   let (dir, projectFileName) = splitFileName rootPath
   projectDir <- makeAbsolute dir
-  projectPath <- canonicalizeConfigPath projectDir (ProjectConfigPath $ projectFileName :| [])
-  parseProjectSkeleton cacheDir httpTransport verbosity projectDir projectPath configToParse
+  projectPath@(ProjectConfigPath (canonicalRoot :| _)) <- canonicalizeConfigPath projectDir (ProjectConfigPath $ projectFileName :| [])
+  importsBy :: IORef [(FilePath, ProjectConfigPath)] <- newIORef [(canonicalRoot, projectPath)]
+  parseProjectSkeleton cacheDir httpTransport verbosity importsBy projectDir projectPath configToParse
 
 parseProjectSkeleton
   :: FilePath
   -> HttpTransport
   -> Verbosity
+  -> IORef [(FilePath, ProjectConfigPath)]
   -> FilePath
   -- ^ The directory of the project configuration, typically the directory of cabal.project
   -> ProjectConfigPath
   -- ^ The path of the file being parsed, either the root or an import
   -> ProjectConfigToParse
   -- ^ The contents of the file to parse
   -> IO (ParseResult ProjectConfigSkeleton)
-parseProjectSkeleton cacheDir httpTransport verbosity projectDir source (ProjectConfigToParse bs) =
+parseProjectSkeleton cacheDir httpTransport verbosity importsBy projectDir source (ProjectConfigToParse bs) =
   (sanityWalkPCS False =<<) <$> liftPR (go []) (ParseUtils.readFields bs)
   where
     go :: [ParseUtils.Field] -> [ParseUtils.Field] -> IO (ParseResult ProjectConfigSkeleton)
     go acc (x : xs) = case x of
       (ParseUtils.F _ "import" importLoc) -> do
         let importLocPath = importLoc `consProjectConfigPath` source
 
-        -- Once we canonicalize the import path, we can check for cyclical imports
-        normLocPath <- canonicalizeConfigPath projectDir importLocPath
+        -- Once we canonicalize the import path, we can check for cyclical and duplicate imports
+        normLocPath@(ProjectConfigPath (uniqueImport :| _)) <- canonicalizeConfigPath projectDir importLocPath
+        seenImportsBy@(fmap fst -> seenImports) <- atomicModifyIORef' importsBy (\ibs -> (nub $ (uniqueImport, normLocPath) : ibs, ibs))
 
         debug verbosity $ "\nimport path, normalized\n=======================\n" ++ render (docProjectConfigPath normLocPath)
-
-        if isCyclicConfigPath normLocPath
-          then pure . parseFail $ ParseUtils.FromString (render $ cyclicalImportMsg normLocPath) Nothing
-          else do
-            normSource <- canonicalizeConfigPath projectDir source
-            let fs = (\z -> CondNode z [normLocPath] mempty) <$> fieldsToConfig normSource (reverse acc)
-            res <- parseProjectSkeleton cacheDir httpTransport verbosity projectDir importLocPath . ProjectConfigToParse =<< fetchImportConfig normLocPath
-            rest <- go [] xs
-            pure . fmap mconcat . sequence $ [fs, res, rest]
+        debug verbosity "\nseen unique paths\n================="
+        mapM_ (debug verbosity . fst) seenImportsBy
+        debug verbosity "\n"
+
+        if
+            | isCyclicConfigPath normLocPath ->
+                pure . parseFail $ ParseUtils.FromString (render $ cyclicalImportMsg normLocPath) Nothing
+            | uniqueImport `elem` seenImports -> do
+                let dupImportsBy = filter ((uniqueImport ==) . fst) seenImportsBy
+                pure . parseFail $ ParseUtils.FromString (render $ duplicateImportMsg uniqueImport normLocPath dupImportsBy) Nothing
+            | otherwise -> do
+                normSource <- canonicalizeConfigPath projectDir source
+                let fs = (\z -> CondNode z [normLocPath] mempty) <$> fieldsToConfig normSource (reverse acc)
+                res <- parseProjectSkeleton cacheDir httpTransport verbosity importsBy projectDir importLocPath . ProjectConfigToParse =<< fetchImportConfig normLocPath
+                rest <- go [] xs
+                pure . fmap mconcat . sequence $ [fs, res, rest]
       (ParseUtils.Section l "if" p xs') -> do
         subpcs <- go [] xs'
         let fs = singletonProjectConfigSkeleton <$> fieldsToConfig source (reverse acc)

cabal-testsuite/PackageTests/ConditionalAndImport/cabal.out

@@ -126,7 +126,15 @@ Could not resolve dependencies:
 After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: hashable (3), oops (2)
 # checking that we detect when the same config is imported via many different paths
 # cabal v2-build
-Up to date
+Error: [Cabal-7090]
+Error parsing project file <ROOT>/yops-0.project:
+duplicate import of yops/yops-3.config;
+  yops/yops-3.config
+    imported by: yops-0.project
+  yops/yops-3.config
+    imported by: yops-2.config
+    imported by: yops/yops-1.config
+    imported by: yops-0.project
 # checking bad conditional
 # cabal v2-build
 Error: [Cabal-7090]