From e5eb53adceaa5ba6e0a9e3e897e5b8dde053a703 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sat, 18 Jul 2026 13:34:31 +0200
Subject: [PATCH 1/9] Add spec for newline detection

---
 test/Core/NewlineSpec.hs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 test/Core/NewlineSpec.hs

diff --git a/test/Core/NewlineSpec.hs b/test/Core/NewlineSpec.hs
new file mode 100644
index 00000000..59bb68fd
--- /dev/null
+++ b/test/Core/NewlineSpec.hs
@@ -0,0 +1,17 @@
+module Core.NewlineSpec (spec) where
+
+import JbeamEdit.Core.Newline (detectNewline)
+import System.IO (Newline (..))
+import Test.Hspec
+
+spec :: Spec
+spec =
+  describe "detectNewline" $ do
+    it "detects LF for unix line endings" $
+      detectNewline "a\nb\n" `shouldBe` LF
+    it "detects CRLF for windows line endings" $
+      detectNewline "a\r\nb\r\n" `shouldBe` CRLF
+    it "detects CRLF when line endings are mixed" $
+      detectNewline "a\r\nb\n" `shouldBe` CRLF
+    it "defaults to LF when there is no line ending" $
+      detectNewline "abc" `shouldBe` LF

From 37078edbed219c0ddd7f6ce574f5e9f5977e9309 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sat, 8 Aug 2026 23:49:15 +0200
Subject: [PATCH 2/9] Implemented newline detection support

---
 jbeam-edit.cabal              |  2 ++
 src/JbeamEdit/Core/Newline.hs | 14 ++++++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 src/JbeamEdit/Core/Newline.hs

diff --git a/jbeam-edit.cabal b/jbeam-edit.cabal
index a60dfd62..2bcb3ec6 100644
--- a/jbeam-edit.cabal
+++ b/jbeam-edit.cabal
@@ -63,6 +63,7 @@ flag windows-example-paths
 
 library
     exposed-modules:
+        JbeamEdit.Core.Newline
         JbeamEdit.Core.Node
         JbeamEdit.Core.NodeCursor
         JbeamEdit.Core.NodePath
@@ -262,6 +263,7 @@ test-suite jbeam-edit-test
     build-tool-depends: hspec-discover:hspec-discover
     hs-source-dirs:     test
     other-modules:
+        Core.NewlineSpec
         Core.NodeCursorSpec
         Core.NodePathSpec
         Core.NodeSpec
diff --git a/src/JbeamEdit/Core/Newline.hs b/src/JbeamEdit/Core/Newline.hs
new file mode 100644
index 00000000..6071d102
--- /dev/null
+++ b/src/JbeamEdit/Core/Newline.hs
@@ -0,0 +1,14 @@
+module JbeamEdit.Core.Newline (detectNewline) where
+
+import Data.ByteString.Lazy as LBS
+import Data.ByteString.Lazy.Char8 as LBS8 (elemIndex)
+import System.IO (Newline (..))
+
+detectNewline :: LBS.ByteString -> Newline
+detectNewline content =
+  case LBS8.elemIndex '\r' content of
+    Nothing -> LF
+    Just idx ->
+      case LBS.index content (idx + 1) of
+        10 -> CRLF  -- '\n'
+        _  -> detectNewline (LBS.drop (idx + 1) content)

From 44349fb13ec78f90bb26bef565dfb70d585a160e Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sat, 8 Aug 2026 23:51:14 +0200
Subject: [PATCH 3/9] Added GHC 9.8.4 to ghc list

---
 jbeam-edit.cabal                                                | 2 +-
 package.yaml                                                    | 2 +-
 src-extra/transformation/JbeamEdit/Transformation.hs            | 2 +-
 .../transformation/JbeamEdit/Transformation/BeamValidation.hs   | 1 +
 4 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/jbeam-edit.cabal b/jbeam-edit.cabal
index 2bcb3ec6..aaeb4bd4 100644
--- a/jbeam-edit.cabal
+++ b/jbeam-edit.cabal
@@ -11,7 +11,7 @@ license-file:       LICENSE
 copyright:          2025 webdevred
 maintainer:         example@example.com
 author:             webdevred
-tested-with:        ghc ==9.10.3 ghc ==9.14.1
+tested-with:        ghc ==9.8.4 ghc ==9.10.3 ghc ==9.14.1
 homepage:           https://github.com/webdevred/jbeam-edit#readme
 bug-reports:        https://github.com/webdevred/jbeam-edit/issues
 synopsis:
diff --git a/package.yaml b/package.yaml
index e07ccea6..0ea56827 100644
--- a/package.yaml
+++ b/package.yaml
@@ -25,7 +25,7 @@ description: >-
   and can automatically rename nodes and update references. Custom formatting rules
   are supported via JBFL (JBeam Formatting Language). See the README for usage instructions
   and examples: https://github.com/webdevred/jbeam-edit#readme
-tested-with: [GHC == 9.10.3, GHC == 9.14.1]
+tested-with: [GHC == 9.8.4, GHC == 9.10.3, GHC == 9.14.1]
 
 dependencies:
   - base >= 4.19
diff --git a/src-extra/transformation/JbeamEdit/Transformation.hs b/src-extra/transformation/JbeamEdit/Transformation.hs
index 8e043502..34681f0e 100644
--- a/src-extra/transformation/JbeamEdit/Transformation.hs
+++ b/src-extra/transformation/JbeamEdit/Transformation.hs
@@ -5,7 +5,7 @@ import Data.Bifunctor (first)
 import Data.Bool (bool)
 import Data.Foldable.Extra (notNull)
 import Data.Function (on)
-import Data.List (partition)
+import Data.List (foldl', partition)
 import Data.List.NonEmpty (NonEmpty)
 import Data.List.NonEmpty qualified as NE
 import Data.Map (Map)
diff --git a/src-extra/transformation/JbeamEdit/Transformation/BeamValidation.hs b/src-extra/transformation/JbeamEdit/Transformation/BeamValidation.hs
index f0c3aee3..e4e34df3 100644
--- a/src-extra/transformation/JbeamEdit/Transformation/BeamValidation.hs
+++ b/src-extra/transformation/JbeamEdit/Transformation/BeamValidation.hs
@@ -7,6 +7,7 @@ module JbeamEdit.Transformation.BeamValidation (
 ) where
 
 import Control.Monad (forM_, unless)
+import Data.List (foldl')
 import Data.List.NonEmpty (toList)
 import Data.Map qualified as M
 import Data.Set (Set)

From 5b28fb07819041c775998c91a80300c10c710417 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sat, 8 Aug 2026 23:55:47 +0200
Subject: [PATCH 4/9] Ran fourmolu

---
 src/JbeamEdit/Core/Newline.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/JbeamEdit/Core/Newline.hs b/src/JbeamEdit/Core/Newline.hs
index 6071d102..15c21338 100644
--- a/src/JbeamEdit/Core/Newline.hs
+++ b/src/JbeamEdit/Core/Newline.hs
@@ -10,5 +10,5 @@ detectNewline content =
     Nothing -> LF
     Just idx ->
       case LBS.index content (idx + 1) of
-        10 -> CRLF  -- '\n'
-        _  -> detectNewline (LBS.drop (idx + 1) content)
+        10 -> CRLF -- '\n'
+        _ -> detectNewline (LBS.drop (idx + 1) content)

From 96637779f800314022305b6eb755806f2250f844 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sun, 9 Aug 2026 00:04:52 +0200
Subject: [PATCH 5/9] Fixed impartial function call

---
 src/JbeamEdit/Core/Newline.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/JbeamEdit/Core/Newline.hs b/src/JbeamEdit/Core/Newline.hs
index 15c21338..9c402f4d 100644
--- a/src/JbeamEdit/Core/Newline.hs
+++ b/src/JbeamEdit/Core/Newline.hs
@@ -9,6 +9,6 @@ detectNewline content =
   case LBS8.elemIndex '\r' content of
     Nothing -> LF
     Just idx ->
-      case LBS.index content (idx + 1) of
-        10 -> CRLF -- '\n'
+      case LBS.uncons (LBS.drop (idx+1) content) of
+        Just (10, _) -> CRLF -- '\n'
         _ -> detectNewline (LBS.drop (idx + 1) content)

From 76038e7da8a2619f6a3c0f61b9228fd344d7b231 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sun, 9 Aug 2026 00:36:33 +0200
Subject: [PATCH 6/9] Wire the new newline detection into the IO code

---
 exe/jbeam-edit/Main.hs      |  9 +++++----
 src/JbeamEdit/Formatting.hs | 19 ++++++++++++-------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/exe/jbeam-edit/Main.hs b/exe/jbeam-edit/Main.hs
index c65c9e25..b19b15b2 100644
--- a/exe/jbeam-edit/Main.hs
+++ b/exe/jbeam-edit/Main.hs
@@ -12,6 +12,7 @@ import JbeamEdit.IOUtils
 import JbeamEdit.Parsing.Jbeam (parseNodes)
 import System.Directory.OsPath
 import System.Environment (getArgs)
+import System.IO (Newline)
 import System.OsPath
 
 #ifdef ENABLE_WINDOWS_NEWLINES
@@ -49,15 +50,15 @@ editFile opts = do
       createBackupFile filename opts
       contents <- tryReadFile [] filename
       case contents >>= parseNodes of
-        Right ns -> processNodes opts filename ns formattingConfig
+        Right ns -> processNodes (detectNewline contents) opts filename ns formattingConfig
         Left err -> putErrorLine err
     Nothing -> putErrorLine "missing arg filename"
 
-processNodes :: Options -> OsPath -> Node -> RuleSet -> IO ()
-processNodes opts outFile nodes formattingConfig = do
+processNodes :: Newline -> Options -> OsPath -> Node -> RuleSet -> IO ()
+processNodes newline opts outFile nodes formattingConfig = do
   transformedNode <- applyTransform formattingConfig opts nodes
   case transformedNode of
-    Right transformedNode' -> formatNodeAndWrite formattingConfig outFile transformedNode'
+    Right transformedNode' -> formatNodeAndWrite newline formattingConfig outFile transformedNode'
     Left err -> putErrorLine err
 
 applyTransform :: RuleSet -> Options -> Node -> IO (Either Text Node)
diff --git a/src/JbeamEdit/Formatting.hs b/src/JbeamEdit/Formatting.hs
index 320f0a06..b5a51c1c 100644
--- a/src/JbeamEdit/Formatting.hs
+++ b/src/JbeamEdit/Formatting.hs
@@ -10,8 +10,9 @@ module JbeamEdit.Formatting (
   emptyState,
 ) where
 
+import System.IO
 import Data.Bool (bool)
-import Data.ByteString.Lazy qualified as LBS (fromStrict)
+import Data.ByteString.Lazy qualified as LBS (fromStrict,hPutStr)
 import Data.Char (isSpace)
 import Data.Foldable.Extra (notNull)
 import Data.Map.Strict (Map)
@@ -51,7 +52,7 @@ import JbeamEdit.Formatting.Rules (
  )
 import JbeamEdit.Formatting.Rules.ComplexNewLine qualified as CNL
 import JbeamEdit.Formatting.Rules.TrailingComma qualified as TC
-import System.File.OsPath qualified as OS (writeFile)
+import System.File.OsPath qualified as OS
 import System.OsPath (OsPath)
 
 data FormattingState = FormattingState
@@ -468,13 +469,17 @@ replaceNewlines = id
 #endif
 
 formatNodeAndWrite
-  :: RuleSet
+  :: Newline
+  -> RuleSet
   -> OsPath
   -> Node
   -> IO ()
-formatNodeAndWrite rs outFile =
-  OS.writeFile outFile
-    . LBS.fromStrict
+formatNodeAndWrite newline rs outFile node = do
+  handle <- OS.openFile outFile WriteMode
+  hSetNewlineMode handle (NewlineMode LF newline)
+  LBS.hPutStr handle .
+    LBS.fromStrict
     . encodeUtf8
     . replaceNewlines
-    . formatNode rs
+    $ formatNode rs node
+  hClose handle

From de26d4b03d4eb78aad054235c0ea160d397cc385 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sun, 9 Aug 2026 00:45:22 +0200
Subject: [PATCH 7/9] Use the the newline detection in cross file update code

---
 .../transformation/JbeamEdit/Transformation.hs   | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src-extra/transformation/JbeamEdit/Transformation.hs b/src-extra/transformation/JbeamEdit/Transformation.hs
index 34681f0e..081e5142 100644
--- a/src-extra/transformation/JbeamEdit/Transformation.hs
+++ b/src-extra/transformation/JbeamEdit/Transformation.hs
@@ -24,6 +24,7 @@ import Data.Traversable (mapAccumL)
 import Data.Vector (Vector, (!), (!?), (//))
 import Data.Vector qualified as V
 import GHC.IsList
+import JbeamEdit.Core.Newline
 import JbeamEdit.Core.Node
 import JbeamEdit.Core.NodeCursor (newCursor)
 import JbeamEdit.Core.NodeCursor qualified as NC
@@ -492,12 +493,15 @@ filterJbeamFiles excludedFilenames = filter go
 updateOtherFiles :: RuleSet -> UpdateNamesMap -> OsPath -> IO ()
 updateOtherFiles formattingConfig updatedNames filepath = do
   contents <- tryReadFile [] filepath
-  case contents >>= parseNodes of
-    Right node ->
-      let node' = findAndUpdateTextInNode updatedNames newCursor node
-       in when
-            (node /= node')
-            (formatNodeAndWrite formattingConfig filepath node')
+  case contents of
+    Right contents' ->
+      case parseNodes contents' of
+        Right node ->
+          let node' = findAndUpdateTextInNode updatedNames newCursor node
+           in when
+                (node /= node')
+                (formatNodeAndWrite (detectNewline contents') formattingConfig filepath node')
+        Left err -> putErrorLine err
     Left err -> putErrorLine err
 
 transform

From 1e38334543e9847d0bf1bd04150cc83c0e5b9464 Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sun, 9 Aug 2026 00:47:10 +0200
Subject: [PATCH 8/9] Ran fourmolu

---
 src/JbeamEdit/Core/Newline.hs | 2 +-
 src/JbeamEdit/Formatting.hs   | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/JbeamEdit/Core/Newline.hs b/src/JbeamEdit/Core/Newline.hs
index 9c402f4d..fb11267f 100644
--- a/src/JbeamEdit/Core/Newline.hs
+++ b/src/JbeamEdit/Core/Newline.hs
@@ -9,6 +9,6 @@ detectNewline content =
   case LBS8.elemIndex '\r' content of
     Nothing -> LF
     Just idx ->
-      case LBS.uncons (LBS.drop (idx+1) content) of
+      case LBS.uncons (LBS.drop (idx + 1) content) of
         Just (10, _) -> CRLF -- '\n'
         _ -> detectNewline (LBS.drop (idx + 1) content)
diff --git a/src/JbeamEdit/Formatting.hs b/src/JbeamEdit/Formatting.hs
index b5a51c1c..42151fe1 100644
--- a/src/JbeamEdit/Formatting.hs
+++ b/src/JbeamEdit/Formatting.hs
@@ -10,9 +10,8 @@ module JbeamEdit.Formatting (
   emptyState,
 ) where
 
-import System.IO
 import Data.Bool (bool)
-import Data.ByteString.Lazy qualified as LBS (fromStrict,hPutStr)
+import Data.ByteString.Lazy qualified as LBS (fromStrict, hPutStr)
 import Data.Char (isSpace)
 import Data.Foldable.Extra (notNull)
 import Data.Map.Strict (Map)
@@ -53,6 +52,7 @@ import JbeamEdit.Formatting.Rules (
 import JbeamEdit.Formatting.Rules.ComplexNewLine qualified as CNL
 import JbeamEdit.Formatting.Rules.TrailingComma qualified as TC
 import System.File.OsPath qualified as OS
+import System.IO
 import System.OsPath (OsPath)
 
 data FormattingState = FormattingState
@@ -477,8 +477,8 @@ formatNodeAndWrite
 formatNodeAndWrite newline rs outFile node = do
   handle <- OS.openFile outFile WriteMode
   hSetNewlineMode handle (NewlineMode LF newline)
-  LBS.hPutStr handle .
-    LBS.fromStrict
+  LBS.hPutStr handle
+    . LBS.fromStrict
     . encodeUtf8
     . replaceNewlines
     $ formatNode rs node

From da50ecd0526d5b006fdfb20f828ae4d9db184b3c Mon Sep 17 00:00:00 2001
From: webdevred <148627186+webdevred@users.noreply.github.com>
Date: Sun, 9 Aug 2026 00:53:08 +0200
Subject: [PATCH 9/9] Fix

---
 exe/jbeam-edit/Main.hs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/exe/jbeam-edit/Main.hs b/exe/jbeam-edit/Main.hs
index b19b15b2..e131583c 100644
--- a/exe/jbeam-edit/Main.hs
+++ b/exe/jbeam-edit/Main.hs
@@ -5,6 +5,7 @@ module Main (
 import CommandLineOptions
 import Control.Monad (when)
 import Data.Text (Text)
+import JbeamEdit.Core.Newline
 import JbeamEdit.Core.Node (Node)
 import JbeamEdit.Formatting (RuleSet, formatNodeAndWrite)
 import JbeamEdit.Formatting.Config
@@ -49,8 +50,11 @@ editFile opts = do
     Just filename -> do
       createBackupFile filename opts
       contents <- tryReadFile [] filename
-      case contents >>= parseNodes of
-        Right ns -> processNodes (detectNewline contents) opts filename ns formattingConfig
+      case contents of
+        Right contents' ->
+          case parseNodes contents' of
+            Right ns -> processNodes (detectNewline contents') opts filename ns formattingConfig
+            Left err -> putErrorLine err
         Left err -> putErrorLine err
     Nothing -> putErrorLine "missing arg filename"