chat : fix multiple tool_calls on hermes-2-pro (#14962)

common/chat.cpp

@@ -1646,7 +1646,7 @@ static void common_chat_parse_hermes_2_pro(common_chat_msg_parser & builder) {
         "|<function name=\"([^\"]+)\">"  // match 5 (function name again)
     );
 
-    if (auto res = builder.try_find_regex(open_regex)) {
+    while (auto res = builder.try_find_regex(open_regex)) {
         const auto & block_start = res->groups[1];
         std::string block_end = block_start.empty() ? "" : "```";
 
@@ -1668,7 +1668,6 @@ static void common_chat_parse_hermes_2_pro(common_chat_msg_parser & builder) {
                     builder.consume_literal(block_end);
                     builder.consume_spaces();
                 }
-                builder.add_content(builder.consume_rest());
             } else {
                 throw common_chat_msg_partial_exception("failed to parse tool call");
             }
@@ -1693,11 +1692,10 @@ static void common_chat_parse_hermes_2_pro(common_chat_msg_parser & builder) {
                     builder.consume_spaces();
                 }
             }
-            builder.add_content(builder.consume_rest());
         }
-    } else {
-        builder.add_content(builder.consume_rest());
     }
+
+    builder.add_content(builder.consume_rest());
 }
 
 static common_chat_params common_chat_params_init_without_tools(const common_chat_template & tmpl, const struct templates_params & inputs) {

tests/test-chat.cpp

@@ -953,6 +953,33 @@ static void test_template_output_parsers() {
                 /* is_partial= */ false,
                 {COMMON_CHAT_FORMAT_HERMES_2_PRO}));
 
+        // Test multiple tool calls
+        common_chat_msg message_assist_multiple_calls;
+        message_assist_multiple_calls.role = "assistant";
+        message_assist_multiple_calls.content = "";
+        message_assist_multiple_calls.tool_calls.push_back({"special_function", "{\"arg1\": 1}", ""});
+        message_assist_multiple_calls.tool_calls.push_back({"python", "{\"code\":\"print('hello')\"}", ""});
+
+        assert_msg_equals(
+            message_assist_multiple_calls,
+            common_chat_parse(
+                "<tool_call>\n"
+                "{\"name\": \"special_function\", \"arguments\": {\"arg1\": 1}}\n"
+                "</tool_call>\n"
+                "<tool_call>\n"
+                "{\"name\": \"python\", \"arguments\": {\"code\":\"print('hello')\"}}\n"
+                "</tool_call>",
+                /* is_partial= */ false,
+                {COMMON_CHAT_FORMAT_HERMES_2_PRO}));
+
+        assert_msg_equals(
+            message_assist_multiple_calls,
+            common_chat_parse(
+                "<function=special_function>{\"arg1\": 1}</function>\n"
+                "<function=python>{\"code\":\"print('hello')\"}</function>",
+                /* is_partial= */ false,
+                {COMMON_CHAT_FORMAT_HERMES_2_PRO}));
+
         assert_msg_equals(
             simple_assist_msg(
                 "This is not a tool call:",
@@ -1039,6 +1066,22 @@ static void test_template_output_parsers() {
                       "<tool_call>\n"
                       "{\"name\": \"special_function\", \"arguments\": {\"arg1\": 1}}\n"
                       "</tool_call>");
+
+        // Test multiple tool calls with template
+        common_chat_msg message_assist_multiple_calls_template;
+        message_assist_multiple_calls_template.role = "assistant";
+        message_assist_multiple_calls_template.content = "";
+        message_assist_multiple_calls_template.tool_calls.push_back({"special_function", "{\"arg1\": 1}", ""});
+        message_assist_multiple_calls_template.tool_calls.push_back({"python", "{\"code\":\"print('test')\"}", ""});
+
+        test_templates(tmpls.get(), end_tokens, message_assist_multiple_calls_template, tools,
+                      "<tool_call>\n"
+                      "{\"name\": \"special_function\", \"arguments\": {\"arg1\": 1}}\n"
+                      "</tool_call>\n"
+                      "<tool_call>\n"
+                      "{\"name\": \"python\", \"arguments\": {\"code\":\"print('test')\"}}\n"
+                      "</tool_call>");
+
         test_templates(tmpls.get(), end_tokens, message_assist_call_python_lines, tools,
                       "<tool_call>\n"
                       "{\"name\": \"python\", \"arguments\": {\"code\":\"# This is a program:\\nprint('hey')\"}}\n"