print received contents on parse error

Author: aldehir

common/chat.cpp

@@ -5,7 +5,6 @@
 #include "json-schema-to-grammar.h"
 #include "log.h"
 #include "regex-partial.h"
-#include "parsers/harmony.h"
 
 #include <minja/chat-template.hpp>
 #include <minja/minja.hpp>
@@ -1366,6 +1365,15 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
     static const common_regex browser_tool_call_regex("browser\\.(search|open|find)[\\s\\S]*<\\|message\\|>");
     static const common_regex python_tool_call_regex("python\\s?(?:<|constrain|>code)?<\\|message\\|>");
 
+    auto consume_until_start = [&]() {
+        if (auto res = builder.try_find_regex(start_regex, std::string::npos, false)) {
+            auto begin = res->groups[0].begin;
+            builder.move_to(begin);
+            return res->prelude;
+        }
+        return builder.consume_rest();
+    };
+
     auto tool_call = [&]() {
         if (auto res = builder.try_consume_regex(user_tool_call_regex)) {
             auto name = builder.str(res->groups[1]);
@@ -1379,7 +1387,7 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
             auto args = builder.consume_rest();
             LOG_DBG("builtin tool call to browser.%s %s", name.c_str(), args.c_str());
         } else {
-            throw common_chat_msg_parse_exception("expected function call");
+            throw common_chat_msg_parse_exception("expected function call, got: " + consume_until_start());
         }
     };
 
@@ -1391,15 +1399,15 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
                 builder.add_content(builder.consume_rest());
             }
         } else {
-            throw common_chat_msg_parse_exception("expected: \" to=\" or <|message|>");
+            throw common_chat_msg_parse_exception("expected: \" to=\" or <|message|>, got: " + consume_until_start());
         }
     };
 
     auto final = [&]() {
         if (builder.try_consume_regex(message_regex)) {
             builder.add_content(builder.consume_rest());
         } else {
-            throw common_chat_msg_parse_exception("expected: <|message|>");
+            throw common_chat_msg_parse_exception("expected: <|message|>, got: " + consume_until_start());
         }
     };
 
@@ -1413,7 +1421,7 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
                 builder.add_reasoning_content(builder.consume_rest());
             }
         } else {
-            throw common_chat_msg_parse_exception("expected: <|message|>");
+            throw common_chat_msg_parse_exception("expected: <|message|>, got: " + consume_until_start());
         }
     };
 
@@ -1430,30 +1438,30 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
                 }
             }
         } else {
-            throw common_chat_msg_parse_exception("expected: <|channel|>");
+            throw common_chat_msg_parse_exception("expected: <|channel|>, got: " + consume_until_start());
         }
     };
 
     auto start = [&]() {
         if (builder.try_consume_regex(assistant_regex)) {
             channel();
         } else {
-            throw common_chat_msg_parse_exception("expected: <|assistant|>");
+            throw common_chat_msg_parse_exception("expected: <|assistant|>, got: " + consume_until_start());
         }
     };
 
     try {
         channel();
     } catch (const common_chat_msg_parse_exception & e) {
-        LOG_ERR("Parse error: %s", e.what());
+        LOG_ERR("Parse error: %s\n", e.what());
     }
 
     // Read in complete messages until done or partial exception raised
     while (builder.try_find_literal("<|start|>")) {
         try {
             start();
         } catch (const common_chat_msg_parse_exception & e) {
-            LOG_ERR("Parse error: %s", e.what());
+            LOG_ERR("Parse error: %s\n", e.what());
         }
     }