fix(trtllm): handle single eos_token_id in generation_config

The type of `eos_token_id` in `transformers.GenerationConfig` is
`Union[int, list[int]]` (as of transformers 4.57.0).

The original code only parses this field when the value is an array, so
the stop_words is not populated for some models.
Add code to handle the `int` case as well.

Author: leejuyuu

backends/trtllm/csrc/backend.hpp

@@ -69,14 +69,23 @@ namespace huggingface::tgi::backends::trtllm {
 
         constexpr explicit generation_config_t(const json &config) :
                 top_p(config.value("top_p", 1.0f)), temperature(config.value("temperature", 1.0f)), stop_words(0) {
-            if (config.contains("/eos_token_id"_json_pointer) && config["/eos_token_id"_json_pointer].is_array()) {
+            if (!config.contains("/eos_token_id"_json_pointer)) {
+                return;
+            }
+            if (config["/eos_token_id"_json_pointer].is_array()) {
+                SPDLOG_DEBUG("generation config eos_token_id is array");
                 const auto &eos_token_id = config["/eos_token_id"_json_pointer];
                 std::for_each(eos_token_id.begin(), eos_token_id.end(), [this](const auto token_id) {
                     stop_words.emplace_back(1, token_id.template get<int32_t>());
                 });
+            }
 
-                SPDLOG_DEBUG("Detected {:d} predefined stop_words from generation_config.json", stop_words.size());
+            if (config["/eos_token_id"_json_pointer].is_number()) {
+                SPDLOG_DEBUG("generation config eos_token_id is number");
+                stop_words.emplace_back(1, config["/eos_token_id"_json_pointer].get<int32_t>());
             }
+
+            SPDLOG_DEBUG("Detected {:d} predefined stop_words from generation_config.json", stop_words.size());
         }
     };