From a5edf3a31184543cffae0fe0045323915b88ce62 Mon Sep 17 00:00:00 2001
From: ryanwyler <ryan@bridgetone.com>
Date: Fri, 9 Jan 2026 10:42:55 -0700
Subject: [PATCH] fix: resolve broken forked sessions with compactions due to
 missing parent-child message references (#6445)

---
 packages/opencode/src/session/index.ts | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index 0776590d6..a204913f7 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -151,12 +151,19 @@ export namespace Session {
         directory: Instance.directory,
       })
       const msgs = await messages({ sessionID: input.sessionID })
+      const idMap = new Map<string, string>()
+
       for (const msg of msgs) {
         if (input.messageID && msg.info.id >= input.messageID) break
+        const newID = Identifier.ascending("message")
+        idMap.set(msg.info.id, newID)
+
+        const parentID = msg.info.role === "assistant" && msg.info.parentID ? idMap.get(msg.info.parentID) : undefined
         const cloned = await updateMessage({
           ...msg.info,
           sessionID: session.id,
-          id: Identifier.ascending("message"),
+          id: newID,
+          ...(parentID && { parentID }),
         })
 
         for (const part of msg.parts) {