Format returns 0 when file is not formatted (#2181)

`format` command now returns code `0` most of the time.

It will return `1` when:
* some error occur, so can not format
* file is unformatted and `--check` option is used
* One or more files are not formatted in a Juvix project.

- Fixes #2171

app/Commands/Format.hs

@@ -19,6 +19,7 @@ data FormatTarget
   = TargetFile
   | TargetDir
   | TargetStdin
+  deriving stock (Eq)
 
 runCommand :: forall r. Members '[Embed IO, App, Resource, Files] r => FormatOptions -> Sem r ()
 runCommand opts = do
@@ -44,7 +45,17 @@ runCommand opts = do
                       "Use the --help option to display more usage information."
                     ]
                 return FormatResultFail
-    when (res == FormatResultFail) (embed (exitWith (ExitFailure 1)))
+    let exitFail :: IO a
+        exitFail = exitWith (ExitFailure 1)
+    case res of
+      FormatResultFail -> embed exitFail
+      FormatResultNotFormatted ->
+        {- use exit code 1 for
+         * unformatted files when using --check
+         * when running the formatter on a Juvix project
+        -}
+        when (opts ^. formatCheck || target == TargetDir) (embed exitFail)
+      FormatResultOK -> pure ()
 
 renderModeFromOptions :: FormatTarget -> FormatOptions -> FormattedFileInfo -> FormatRenderMode
 renderModeFromOptions target opts formattedInfo

src/Juvix/Formatter.hs

@@ -24,13 +24,22 @@ makeSem ''ScopeEff
 
 data FormatResult
   = FormatResultOK
+  | FormatResultNotFormatted
   | FormatResultFail
   deriving stock (Eq)
 
+instance Semigroup FormatResult where
+  FormatResultFail <> _ = FormatResultFail
+  _ <> FormatResultFail = FormatResultFail
+  FormatResultNotFormatted <> _ = FormatResultNotFormatted
+  _ <> FormatResultNotFormatted = FormatResultNotFormatted
+  _ <> _ = FormatResultOK
+
+instance Monoid FormatResult where
+  mempty = FormatResultOK
+
 combineResults :: [FormatResult] -> FormatResult
-combineResults rs
-  | FormatResultFail `elem` rs = FormatResultFail
-  | otherwise = FormatResultOK
+combineResults = mconcat
 
 ansiPlainText :: NonEmpty AnsiText -> Text
 ansiPlainText = T.concat . toList . fmap toPlainText
@@ -43,11 +52,11 @@ formattedFileInfoContentsText = to infoToPlainText
 
 -- | Format a single Juvix file.
 --
--- If the file requires formatting then the function returns FormatResultFail
+-- If the file requires formatting then the function returns 'FormatResultNotFormatted'
 -- and outputs a FormattedFileInfo containing the formatted contents of the file.
 --
 -- If the file does not require formatting then the function returns
--- FormatResultOK and nothing is output.
+-- 'FormatResultOK' and nothing is output.
 format ::
   forall r.
   Members '[ScopeEff, Files, Output FormattedFileInfo] r =>
@@ -62,12 +71,12 @@ format p = do
 --
 -- Format all files in the Juvix project containing the passed directory.
 --
--- If any file requires formatting then the function returns FormatResultFail.
+-- If any file requires formatting then the function returns 'FormatResultNotFormatted'
 -- This function also outputs a FormattedFileInfo (containing the formatted
 -- contents of a file) for every file in the project that requires formatting.
 --
 -- If all files in the project are already formatted then the function returns
--- FormatResultOK and nothing is output.
+-- 'FormatResultOK' and nothing is output.
 --
 -- NB: This function does not traverse into Juvix sub-projects, i.e into
 -- subdirectories that contain a juvix.yaml file.
@@ -122,7 +131,7 @@ formatResultFromContents originalContents mfc filepath =
                   _formattedFileInfoContentsAnsi = formattedContents
                 }
             )
-          return FormatResultFail
+          return FormatResultNotFormatted
       | otherwise -> return FormatResultOK
     Nothing ->
       return FormatResultOK

test/Formatter/Positive.hs

@@ -25,7 +25,8 @@ makeFormatTest' Scope.PosTest {..} =
             d <- runM $ runError $ runOutputList @FormattedFileInfo $ runScopeEffIO $ runFilesIO $ format file'
             case d of
               Right (_, FormatResultOK) -> return ()
-              Right (_, FormatResultFail) -> assertFailure ("File: " <> show file' <> " is not formatted")
+              Right (_, FormatResultNotFormatted) -> assertFailure ("File: " <> show file' <> " is not formatted")
+              Right (_, FormatResultFail) -> assertFailure ("File: " <> show file' <> " is failed to format")
               Left {} -> assertFailure ("Error: ")
         }
 

tests/smoke/Commands/format.smoke.yaml

@@ -31,7 +31,7 @@ tests:
         juvix format Foo.juvix
     stdout:
       contains: module Foo;
-    exit-status: 1
+    exit-status: 0
 
   - name: format-unformatted-file-check-no-stdout
     command:
@@ -168,7 +168,7 @@ tests:
 
         main : Nat;
         main := 5;
-    exit-status: 1
+    exit-status: 0
 
   - name: format-stdin-file-does-not-exist
     command:
@@ -207,7 +207,7 @@ tests:
 
         main : Nat;
         main := 5;
-    exit-status: 1
+    exit-status: 0
 
   - name: format-no-stdin-no-file-name
     command: