From 3d9f9a2889aca53ea8d477d036002729ec851c89 Mon Sep 17 00:00:00 2001
From: George Thomas <georgefsthomas@gmail.com>
Date: Sun, 12 Jun 2022 15:59:49 +0200
Subject: [PATCH 1/3] Support Fourmolu 0.7 in CLI mode

Fourmolu 0.7 (due to Ormolu 0.5) removes the `--cabal-default-extensions` flag, instead looking for Cabal files by default. If input is taken from stdin and `--stdin-input-file` isn't specified, it therefore fails.

We don't need to make any changes in non-CLI mode because the Cabal file handling logic occurs at a higher level outside the entry point we use to the library (the `ormolu` function).
---
 plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs b/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs
index d981c3b09f..c5cc358ba0 100644
--- a/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs
+++ b/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs
@@ -66,7 +66,7 @@ provider plId ideState typ contents fp fo = withIndefiniteProgress title Cancell
                 (exitCode, out, err) <-
                     readCreateProcessWithExitCode
                         ( proc "fourmolu" $
-                            ["-d"]
+                            ["-d", "--no-cabal"]
                                 <> catMaybes
                                     [ ("--start-line=" <>) . show <$> regionStartLine region
                                     , ("--end-line=" <>) . show <$> regionEndLine region

From 0bbc545300eb014186e48f879394f9ca6d7ed3c8 Mon Sep 17 00:00:00 2001
From: George Thomas <georgefsthomas@gmail.com>
Date: Sun, 12 Jun 2022 16:47:06 +0200
Subject: [PATCH 2/3] Bump index state

Allows us to use Fourmolu 0.7.
---
 cabal.project | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cabal.project b/cabal.project
index 6a392d90ef..6ba4800c5a 100644
--- a/cabal.project
+++ b/cabal.project
@@ -44,7 +44,7 @@ package *
 
 write-ghc-environment-files: never
 
-index-state: 2022-04-30T21:02:45Z
+index-state: 2022-06-12T00:00:00Z
 
 constraints:
   hyphenation +embed,

From 581686c4729f9ce2dd6ca42a7842701ffa165d9a Mon Sep 17 00:00:00 2001
From: George Thomas <georgefsthomas@gmail.com>
Date: Mon, 13 Jun 2022 12:25:21 +0200
Subject: [PATCH 3/3] Only use Fourmolu `--no-cabal` flag on recent versions

---
 .../src/Ide/Plugin/Fourmolu.hs                | 28 +++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs b/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs
index c5cc358ba0..d3d8c59cea 100644
--- a/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs
+++ b/plugins/hls-fourmolu-plugin/src/Ide/Plugin/Fourmolu.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE DataKinds                #-}
 {-# LANGUAGE DisambiguateRecordFields #-}
 {-# LANGUAGE LambdaCase               #-}
+{-# LANGUAGE NamedFieldPuns           #-}
 {-# LANGUAGE OverloadedLabels         #-}
 {-# LANGUAGE OverloadedStrings        #-}
 {-# LANGUAGE TypeApplications         #-}
@@ -63,10 +64,26 @@ provider plId ideState typ contents fp fo = withIndefiniteProgress title Cancell
             . fmap (join . first (mkError . show))
             . try @IOException
             $ do
-                (exitCode, out, err) <-
+                CLIVersionInfo{noCabal} <- do -- check Fourmolu version so that we know which flags to use
+                    (exitCode, out, _err) <- readCreateProcessWithExitCode ( proc "fourmolu" ["-v"] ) ""
+                    let version = do
+                            guard $ exitCode == ExitSuccess
+                            "fourmolu" : v : _ <- pure $ T.words out
+                            pure $ T.splitOn "." v
+                    case version of
+                        Just v -> pure CLIVersionInfo
+                            { noCabal = v >= ["0", "7"]
+                            }
+                        Nothing -> do
+                            T.hPutStrLn stderr "couldn't get Fourmolu version"
+                            pure CLIVersionInfo
+                                { noCabal = True
+                                }
+                (exitCode, out, err) <- -- run Fourmolu
                     readCreateProcessWithExitCode
                         ( proc "fourmolu" $
-                            ["-d", "--no-cabal"]
+                            ["-d"]
+                                <> mwhen noCabal ["--no-cabal"]
                                 <> catMaybes
                                     [ ("--start-line=" <>) . show <$> regionStartLine region
                                     , ("--end-line=" <>) . show <$> regionEndLine region
@@ -163,3 +180,10 @@ convertDynFlags df =
             Cpp -> "-XCPP"
             x   -> "-X" ++ show x
      in pp <> pm <> ex
+
+newtype CLIVersionInfo = CLIVersionInfo
+    { noCabal :: Bool
+    }
+
+mwhen :: Monoid a => Bool -> a -> a
+mwhen b x = if b then x else mempty