From 8800f5e62fa1c9f8a0744215db7fd3e7b7d47554 Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Thu, 15 Jan 2026 09:36:53 +0000
Subject: [PATCH] core: correctly handle errors in withLocalDisplayName for
 postgres (rollback to savepoint) (#6577)

---
 src/Simplex/Chat/Store/Shared.hs | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/Simplex/Chat/Store/Shared.hs b/src/Simplex/Chat/Store/Shared.hs
index 15ec3ec49d..c9dc87b5fa 100644
--- a/src/Simplex/Chat/Store/Shared.hs
+++ b/src/Simplex/Chat/Store/Shared.hs
@@ -581,7 +581,7 @@ withLocalDisplayName db userId displayName action = getLdnSuffix >>= (`tryCreate
     tryCreateName ldnSuffix attempts = do
       currentTs <- getCurrentTime
       let ldn = displayName <> (if ldnSuffix == 0 then "" else T.pack $ '_' : show ldnSuffix)
-      E.try (insertName ldn currentTs) >>= \case
+      withSavepoint db "ldn_insert" (insertName ldn currentTs) >>= \case
         Right () -> action ldn
         Left e
           | constraintError e -> tryCreateName (ldnSuffix + 1) (attempts - 1)
@@ -597,6 +597,25 @@ withLocalDisplayName db userId displayName action = getLdnSuffix >>= (`tryCreate
             |]
             (ldn, displayName, ldnSuffix, userId, ts, ts)
 
+-- Execute an action within a savepoint (PostgreSQL only).
+-- On success, releases the savepoint. On error, rolls back to the savepoint
+-- to restore the transaction to a usable state before returning the error.
+withSavepoint :: DB.Connection -> Query -> IO a -> IO (Either SQLError a)
+withSavepoint db name action =
+#if defined(dbPostgres)
+  do
+    DB.execute_ db $ "SAVEPOINT " <> name
+    E.try action >>= \case
+      Right r -> do
+        DB.execute_ db $ "RELEASE SAVEPOINT " <> name
+        pure $ Right r
+      Left e -> do
+        DB.execute_ db $ "ROLLBACK TO SAVEPOINT " <> name
+        pure $ Left e
+#else
+  E.try action
+#endif
+
 createWithRandomId :: forall a. TVar ChaChaDRG -> (ByteString -> IO a) -> ExceptT StoreError IO a
 createWithRandomId = createWithRandomBytes 12