From ee1c55a625b30f6481415b4325a39a7fda30a30a Mon Sep 17 00:00:00 2001
From: nimec01 <24428341+nimec01@users.noreply.github.com>
Date: Mon, 20 Apr 2026 10:53:51 +0200
Subject: [PATCH] Log errors to stderr

---
 codeworld-server/src/Main.hs | 11 ++++++++---
 run.sh                       |  2 --
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/codeworld-server/src/Main.hs b/codeworld-server/src/Main.hs
index 0368a739..9ffd3a57 100644
--- a/codeworld-server/src/Main.hs
+++ b/codeworld-server/src/Main.hs
@@ -55,13 +55,14 @@ import Model
 import Network.HTTP.Simple
 import Ormolu (OrmoluException, defaultConfig, ormolu)
 import Snap.Core
-import Snap.Http.Server (httpServe)
-import qualified Snap.Http.Server.Config as S (commandLineConfig, defaultConfig, setPort)
+import Snap.Http.Server (httpServe, ConfigLog (ConfigIoLog))
+import qualified Snap.Http.Server.Config as S (commandLineConfig, defaultConfig, setPort, setErrorLog)
 import Snap.Util.FileServe
 import Snap.Util.FileUploads
 import System.Directory
 import System.FileLock
 import System.FilePath
+import System.IO (stderr)
 import System.IO.Temp
 import System.Environment (lookupEnv)
 import Util
@@ -75,12 +76,16 @@ data Context = Context
     config :: Config
   }
 
+customErrorLog :: ConfigLog
+customErrorLog = ConfigIoLog $ B.hPutStr stderr
+
 main :: IO ()
 main = do
   cfg <- loadConfig
   ctx <- makeContext cfg
   port <- maybe Nothing readMaybe <$> lookupEnv "PORT" :: IO (Maybe Int)
-  cfg <- S.commandLineConfig ((maybe id (\p -> S.setPort p) port) S.defaultConfig)
+  let customDefaultConfig = S.setErrorLog customErrorLog ((maybe id (\p -> S.setPort p) port) S.defaultConfig)
+  cfg <- S.commandLineConfig customDefaultConfig
   forkIO $ baseVersion >>= buildBaseIfNeeded ctx >> return ()
   httpServe cfg $ (processBody >> site ctx) <|> site ctx
 
diff --git a/run.sh b/run.sh
index 519aa457..1fbcda23 100755
--- a/run.sh
+++ b/run.sh
@@ -26,7 +26,5 @@ rm -rf $(for fn in $(find data/base -atime +20 -regex .*\\.js$ ); do dirname $fn
 
 fuser -k -n tcp "${PORT}"
 
-mkdir -p log
-
 export CONFIG_PATH=$(pwd)/config.yaml
 run . ./build/bin/codeworld-server -p $PORT --no-access-log