Shorter file names completion (#4252)

Don't autocomplete `./` in cabal filepaths (e.g. `hs-source-dirs` or `main-is`), unless the user explicitly wrote `./`.

plugins/hls-cabal-plugin/src/Ide/Plugin/Cabal/Completion/Completer/Paths.hs

@@ -1,6 +1,7 @@
 module Ide.Plugin.Cabal.Completion.Completer.Paths where
 
 import qualified Data.List                         as List
+import           Data.List.Extra                   (dropPrefix)
 import qualified Data.Text                         as T
 import           Distribution.PackageDescription   (Benchmark (..),
                                                     BuildInfo (..),
@@ -45,6 +46,32 @@ data PathCompletionInfo = PathCompletionInfo
   }
   deriving (Eq, Show)
 
+
+{- | Posix.splitFileName modification, that drops trailing ./ if
+  if wasn't present in the original path.
+
+  Fix for the issue #3774
+  Examples:
+
+  >>> splitFileNameNoTrailingSlash ""
+  ("", "")
+  >>> splitFileNameNoTrailingSlash "./"
+  ("./", "")
+  >>> splitFileNameNoTrailingSlash "dir"
+  ("", "dir")
+  >>> splitFileNameNoTrailingSlash "./dir"
+  ("./", "dir")
+  >>> splitFileNameNoTrailingSlash "dir1/dir2"
+  ("dir1/","dir2")
+  >>> splitFileNameNoTrailingSlash "./dir1/dir2"
+  ("./dir1/","dir2")
+-}
+splitFileNameNoTrailingSlash :: FilePath -> (String, String)
+splitFileNameNoTrailingSlash prefix = rmTrailingSlash ("./" `List.isPrefixOf` prefix) (Posix.splitFileName prefix)
+  where rmTrailingSlash hadTrailingSlash (queryDirectory', pathSegment')
+                    | hadTrailingSlash = (queryDirectory', pathSegment')
+                    | otherwise        = ("./" `dropPrefix` queryDirectory', pathSegment')
+
 {- | Takes an optional source subdirectory and a prefix info
   and creates a path completion info accordingly.
 
@@ -64,7 +91,7 @@ pathCompletionInfoFromCabalPrefixInfo srcDir prefInfo =
     }
   where
     prefix = T.unpack $ completionPrefix prefInfo
-    (queryDirectory', pathSegment') = Posix.splitFileName prefix
+    (queryDirectory', pathSegment') = splitFileNameNoTrailingSlash prefix
 
 -- | Extracts the source directories of the library stanza.
 sourceDirsExtractionLibrary :: Maybe StanzaName -> GenericPackageDescription -> [FilePath]

plugins/hls-cabal-plugin/test/Completer.hs

@@ -55,8 +55,8 @@ basicCompleterTests =
         doc <- openDoc "main-is.cabal" "cabal"
         compls <- getCompletions doc (Position 10 12)
         let complTexts = getTextEditTexts compls
-        liftIO $ assertBool "suggests f2" $ "./f2.hs" `elem` complTexts
-        liftIO $ assertBool "does not suggest" $ "./Content.hs" `notElem` complTexts
+        liftIO $ assertBool "suggests f2" $ "f2.hs" `elem` complTexts
+        liftIO $ assertBool "does not suggest" $ "Content.hs" `notElem` complTexts
     ]
     where
       getTextEditTexts :: [CompletionItem] -> [T.Text]
@@ -66,21 +66,21 @@ fileCompleterTests :: TestTree
 fileCompleterTests =
   testGroup
     "File Completer Tests"
-    [ testCase "Current Directory" $ do
+    [ testCase "Current Directory - no leading ./ by default" $ do
         completions <- completeFilePath "" filePathComplTestDir
-        completions @?== ["./.hidden", "./Content.hs", "./dir1/", "./dir2/", "./textfile.txt", "./main-is.cabal"],
+        completions @?== [".hidden", "Content.hs", "dir1/", "dir2/", "textfile.txt", "main-is.cabal"],
       testCase "Current Directory - alternative writing" $ do
         completions <- completeFilePath "./" filePathComplTestDir
         completions @?== ["./.hidden", "./Content.hs", "./dir1/", "./dir2/", "./textfile.txt", "./main-is.cabal"],
       testCase "Current Directory - hidden file start" $ do
         completions <- completeFilePath "." filePathComplTestDir
-        completions @?== ["./Content.hs", "./.hidden", "./textfile.txt", "./main-is.cabal"],
+        completions @?== ["Content.hs", ".hidden", "textfile.txt", "main-is.cabal"],
       testCase "Current Directory - incomplete directory path written" $ do
         completions <- completeFilePath "di" filePathComplTestDir
-        completions @?== ["./dir1/", "./dir2/"],
+        completions @?== ["dir1/", "dir2/"],
       testCase "Current Directory - incomplete filepath written" $ do
         completions <- completeFilePath "te" filePathComplTestDir
-        completions @?== ["./Content.hs", "./textfile.txt"],
+        completions @?== ["Content.hs", "textfile.txt"],
       testCase "Subdirectory" $ do
         completions <- completeFilePath "dir1/" filePathComplTestDir
         completions @?== ["dir1/f1.txt", "dir1/f2.hs"],
@@ -165,15 +165,15 @@ directoryCompleterTests :: TestTree
 directoryCompleterTests =
   testGroup
     "Directory Completer Tests"
-    [ testCase "Current Directory" $ do
+    [ testCase "Current Directory - no leading ./ by default" $ do
         completions <- completeDirectory "" filePathComplTestDir
-        completions @?== ["./dir1/", "./dir2/"],
+        completions @?== ["dir1/", "dir2/"],
       testCase "Current Directory - alternative writing" $ do
         completions <- completeDirectory "./" filePathComplTestDir
         completions @?== ["./dir1/", "./dir2/"],
       testCase "Current Directory - incomplete directory path written" $ do
         completions <- completeDirectory "di" filePathComplTestDir
-        completions @?== ["./dir1/", "./dir2/"],
+        completions @?== ["dir1/", "dir2/"],
       testCase "Current Directory - incomplete filepath written" $ do
         completions <- completeDirectory "te" filePathComplTestDir
         completions @?== [],

plugins/hls-cabal-plugin/test/Context.hs

@@ -31,12 +31,12 @@ pathCompletionInfoFromCompletionContextTests :: TestTree
 pathCompletionInfoFromCompletionContextTests =
     testGroup
         "Completion Info to Completion Context Tests"
-        [ testCase "Current Directory" $ do
+        [ testCase "Current Directory - no leading ./ by default" $ do
             let complInfo = pathCompletionInfoFromCabalPrefixInfo "" $ simpleCabalPrefixInfoFromFp "" testDataDir
-            queryDirectory complInfo @?= "./"
+            queryDirectory complInfo @?= ""
         , testCase "Current Directory - partly written next" $ do
             let complInfo = pathCompletionInfoFromCabalPrefixInfo "" $ simpleCabalPrefixInfoFromFp "di" testDataDir
-            queryDirectory complInfo @?= "./"
+            queryDirectory complInfo @?= ""
             pathSegment complInfo @?= "di"
         , testCase "Current Directory - alternative writing" $ do
             let complInfo = pathCompletionInfoFromCabalPrefixInfo "" $ simpleCabalPrefixInfoFromFp "./" testDataDir