From c35189d83c91aad780aba62b89f2830cb2916223 Mon Sep 17 00:00:00 2001
From: gapeleon <191471103+gapeleon@users.noreply.github.com>
Date: Mon, 18 May 2026 01:26:45 +1000
Subject: [PATCH] fix(server): reset chat parser on slot reuse to prevent crash
 (#1763) (#1794)

If a slot is reused for a standard completion (`/v1/completions`) after
being used for a chat completion (`/v1/chat/completions`), the previous
chat's PEG parser would remain active in the slot's parameters. This
caused standard text completions to throw on the raw text.
---
 examples/server/server-context.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/examples/server/server-context.cpp b/examples/server/server-context.cpp
index 69217ba2..b91149ce 100644
--- a/examples/server/server-context.cpp
+++ b/examples/server/server-context.cpp
@@ -1624,6 +1624,9 @@ bool server_context::launch_slot_with_task(server_slot& slot, server_task& task)
         slot.params.chat_parser_params.parse_tool_calls = json_value(data, "parse_tool_calls", false);
         if (data.contains("chat_parser")) {
             slot.params.chat_parser_params.parser.load(data.at("chat_parser").get<std::string>());
+        } else {
+            // Reset to default; otherwise a reused slot would apply the previous chat's PEG parser to non-chat outputs (e.g., /v1/completions).
+            slot.params.chat_parser_params.parser = defaults.chat_parser_params.parser;
         }
     }
     {