When llama_chat_apply_template doesn't work

Try minja. With granite-code if we fall back to jinja on failure,
it's fine.

Co-authored-by: Michael Engel <mengel@redhat.com>
Signed-off-by: Eric Curtin <ecurtin@redhat.com>

examples/run/run.cpp

@@ -837,37 +837,50 @@ static void add_message(const char * role, const std::string & text, LlamaData &
     llama_data.messages.push_back({ role, llama_data.msg_strs.back().c_str() });
 }
 
+// Function to handle Jinja template application
+static int handle_jinja_template(const common_chat_template & tmpl, LlamaData & llama_data, const bool append) {
+    json messages = json::array();
+    for (const auto & msg : llama_data.messages) {
+        messages.push_back({
+            { "role",    msg.role    },
+            { "content", msg.content },
+        });
+    }
+
+    try {
+        minja::chat_template_inputs tmpl_inputs;
+        tmpl_inputs.messages              = messages;
+        tmpl_inputs.add_generation_prompt = append;
+
+        minja::chat_template_options tmpl_opts;
+        tmpl_opts.use_bos_token = false;
+        tmpl_opts.use_eos_token = false;
+
+        auto result = tmpl.apply(tmpl_inputs, tmpl_opts);
+        llama_data.fmtted.resize(result.size() + 1);
+        memcpy(llama_data.fmtted.data(), result.c_str(), result.size() + 1);
+        return result.size();
+    } catch (const std::exception & e) {
+        printe("failed to render the chat template: %s\n", e.what());
+    }
+
+    return -1;
+}
+
 // Function to apply the chat template and resize `formatted` if needed
 static int apply_chat_template(const common_chat_template & tmpl, LlamaData & llama_data, const bool append, bool use_jinja) {
     if (use_jinja) {
-        json messages = json::array();
+        return handle_jinja_template(tmpl, llama_data, append);
-        for (const auto & msg : llama_data.messages) {
-            messages.push_back({
-                {"role", msg.role},
-                {"content", msg.content},
-            });
-        }
-        try {
-            minja::chat_template_inputs tmpl_inputs;
-            tmpl_inputs.messages = messages;
-            tmpl_inputs.add_generation_prompt = append;
-
-            minja::chat_template_options tmpl_opts;
-            tmpl_opts.use_bos_token = false;
-            tmpl_opts.use_eos_token = false;
-
-            auto result = tmpl.apply(tmpl_inputs, tmpl_opts);
-            llama_data.fmtted.resize(result.size() + 1);
-            memcpy(llama_data.fmtted.data(), result.c_str(), result.size() + 1);
-            return result.size();
-        } catch (const std::exception & e) {
-            printe("failed to render the chat template: %s\n", e.what());
-            return -1;
-        }
     }
+
     int result = llama_chat_apply_template(
         tmpl.source().c_str(), llama_data.messages.data(), llama_data.messages.size(), append,
         append ? llama_data.fmtted.data() : nullptr, append ? llama_data.fmtted.size() : 0);
+    // If llama_chat_apply_template fails to apply template, fallback to using jinja
+    if (result < 0) {
+        return handle_jinja_template(tmpl, llama_data, append);
+    }
+
     if (append && result > static_cast<int>(llama_data.fmtted.size())) {
         llama_data.fmtted.resize(result);
         result = llama_chat_apply_template(tmpl.source().c_str(), llama_data.messages.data(),

examples/server/server.cpp

@@ -1895,30 +1895,44 @@ struct server_context {
         return true;
     }
 
+    bool apply_jinja_templates() const {
+        auto               templates = common_chat_templates_from_model(model, "");
+        common_chat_inputs inputs;
+        inputs.messages = json::array({
+            {
+             { "role", "user" },
+             { "content", "test" },
+             }
+        });
+        GGML_ASSERT(templates.template_default);
+        try {
+            common_chat_params_init(*templates.template_default, inputs);
+            if (templates.template_tool_use) {
+                common_chat_params_init(*templates.template_tool_use, inputs);
+            }
+
+            return true;
+        } catch (const std::exception & e) {
+            SRV_ERR("failed to apply template: %s\n", e.what());
+
+            return false;
+        }
+    }
+
     bool validate_builtin_chat_template(bool use_jinja) const {
-        llama_chat_message chat[] = {{"user", "test"}};
+        llama_chat_message chat[] = {
+            { "user", "test" }
+        };
 
         if (use_jinja) {
-            auto templates = common_chat_templates_from_model(model, "");
+            return apply_jinja_templates();
-            common_chat_inputs inputs;
-            inputs.messages = json::array({{
-                {"role", "user"},
-                {"content", "test"},
-            }});
-            GGML_ASSERT(templates.template_default);
-            try {
-                common_chat_params_init(*templates.template_default, inputs);
-                if (templates.template_tool_use) {
-                    common_chat_params_init(*templates.template_tool_use, inputs);
-                }
-                return true;
-            } catch (const std::exception & e) {
-                SRV_ERR("failed to apply template: %s\n", e.what());
-                return false;
-            }
         } else {
-            const char * tmpl = llama_model_chat_template(model, /* name */ nullptr);
+            const char *  tmpl     = llama_model_chat_template(model, /* name */ nullptr);
             const int32_t chat_res = llama_chat_apply_template(tmpl, chat, 1, true, nullptr, 0);
+            if (chat_res < 0) {
+                return apply_jinja_templates();
+            }
+
             return chat_res > 0;
         }
     }