Improve .wasp file checks and messages (#2418)

Author: komyg

waspc/ChangeLog.md

@@ -97,6 +97,8 @@ Read more about breaking changes in the migration guide: https://wasp.sh/docs/mi
 
 Big thanks to our community members who contributed to this release! @Bojun-Feng @dabrorius @komyg @NathanaelA @vblazenka @genyus
 
+- Improved the error message when the user has a top level *.wasp* file.
+
 ## 0.15.2
 
 ### 🐞 Bug fixes

waspc/src/Wasp/Project/WaspFile.hs

@@ -4,13 +4,11 @@ module Wasp.Project.WaspFile
   )
 where
 
-import Data.List (find, isSuffixOf)
 import StrongPath
   ( Abs,
     Dir,
     Path',
     castFile,
-    fromAbsDir,
     fromRelFile,
     (</>),
   )
@@ -25,27 +23,33 @@ import Wasp.Project.WaspFile.TypeScript (analyzeWaspTsFile)
 import Wasp.Project.WaspFile.WaspLang (analyzeWaspLangFile)
 import qualified Wasp.Psl.Ast.Schema as Psl.Schema
 import qualified Wasp.Util.IO as IOUtil
+import Wasp.Util.StrongPath (findAllFilesWithSuffix)
 
 findWaspFile :: Path' Abs (Dir WaspProjectDir) -> IO (Either String WaspFilePath)
-findWaspFile waspDir = do
-  files <- fst <$> IOUtil.listDirectory waspDir
-  return $ case (findWaspTsFile files, findWaspLangFile files) of
-    (Just _, Just _) -> Left bothFilesFoundMessage
-    (Nothing, Nothing) -> Left fileNotFoundMessage
-    (Just waspTsFile, Nothing) -> Right waspTsFile
-    (Nothing, Just waspLangFile) -> Right waspLangFile
+findWaspFile projectDir = do
+  filesInProjectDir <- fst <$> IOUtil.listDirectory projectDir
+  let filesEndingWithWasp = findAllFilesWithSuffix ".wasp" filesInProjectDir
+      filesEndingWithWaspTs = findAllFilesWithSuffix ".wasp.ts" filesInProjectDir
+  return $ case (filesEndingWithWasp, filesEndingWithWaspTs) of
+    ([], []) -> Left fileNotFoundMessage
+    (_ : _, _ : _) -> Left bothFilesFoundMessage
+    ([], waspTsFiles) -> case waspTsFiles of
+      [singleWaspTsFile]
+        | fromRelFile singleWaspTsFile == ".wasp.ts" -> Left (makeInvalidFileNameMessage ".wasp.ts")
+        | otherwise -> Right . WaspTs $ castFile (projectDir </> singleWaspTsFile)
+      multipleWaspTsFiles -> Left (makeMultipleFilesMessage "*.wasp.ts" (map fromRelFile multipleWaspTsFiles))
+    (waspLangFiles, []) -> case waspLangFiles of
+      [singleWaspLangFile]
+        | fromRelFile singleWaspLangFile == ".wasp" -> Left (makeInvalidFileNameMessage ".wasp")
+        | otherwise -> Right . WaspLang $ castFile (projectDir </> singleWaspLangFile)
+      multipleWaspFiles -> Left (makeMultipleFilesMessage "*.wasp" (map fromRelFile multipleWaspFiles))
   where
-    findWaspTsFile files = WaspTs <$> findFileThatEndsWith ".wasp.ts" files
-    findWaspLangFile files = WaspLang <$> findFileThatEndsWith ".wasp" files
-    findFileThatEndsWith suffix files =
-      castFile
-        . (waspDir </>)
-        <$> find ((suffix `isSuffixOf`) . fromRelFile) files
-
-    fileNotFoundMessage = "Couldn't find a *.wasp or a *.wasp.ts file in directory " ++ fromAbsDir waspDir ++ " ."
+    fileNotFoundMessage = "Couldn't find the *.wasp or a *.wasp.ts file in the project directory."
     bothFilesFoundMessage =
       "Found both *.wasp and *.wasp.ts files in the project directory. "
         ++ "You must choose how you want to define your app (using Wasp or TypeScript) and only keep one of them."
+    makeMultipleFilesMessage suffix files = "Found multiple " ++ suffix ++ " files in the project directory: " ++ show files ++ ". Please keep only one."
+    makeInvalidFileNameMessage suffix = "Your Wasp file can't be called '" ++ suffix ++ "'. Please rename it to something like [name]" ++ suffix ++ "."
 
 analyzeWaspFile ::
   Path' Abs (Dir WaspProjectDir) ->

waspc/src/Wasp/Util/StrongPath.hs

@@ -4,11 +4,13 @@ module Wasp.Util.StrongPath
     stripProperPrefix,
     splitAbsExtension,
     splitRelExtension,
+    findAllFilesWithSuffix,
   )
 where
 
 import Control.Arrow (first)
 import Control.Monad.Catch (MonadThrow)
+import Data.List (isSuffixOf)
 import qualified Path as P
 import qualified StrongPath as SP
 import qualified StrongPath.Path as SP
@@ -33,3 +35,6 @@ splitAbsExtension path =
 splitRelExtension :: MonadThrow m => SP.Path' (SP.Rel b) (SP.File a) -> m (SP.Path' (SP.Rel b) (SP.File c), String)
 splitRelExtension path =
   first SP.fromPathRelFile <$> P.splitExtension (SP.toPathRelFile path)
+
+findAllFilesWithSuffix :: String -> [SP.Path p r (SP.File f)] -> [SP.Path p r (SP.File f)]
+findAllFilesWithSuffix extension = filter ((extension `isSuffixOf`) . SP.toFilePath)