tests: allow exporting graph ops from HF file without downloading weights (#21182)

* tests: allow exporting graph ops from HF file without downloading weights

* use unique_ptr for llama_context in HF metadata case

* fix missing non-required tensors falling back to type f32

* use unique pointers where possible

* use no_alloc instead of fixing f32 fallback

* fix missing space

common/arg.cpp

@@ -537,9 +537,11 @@ static bool common_params_parse_ex(int argc, char ** argv, common_params_context
     } catch (const std::exception & e) {
         LOG_WRN("HF cache migration failed: %s\n", e.what());
     }
+    // export_graph_ops loads only metadata
+    const bool skip_model_download = ctx_arg.ex == LLAMA_EXAMPLE_EXPORT_GRAPH_OPS;
 
     // maybe handle remote preset
-    if (!params.model.hf_repo.empty()) {
+    if (!params.model.hf_repo.empty() && !skip_model_download) {
         std::string cli_hf_repo = params.model.hf_repo;
         bool has_preset = common_params_handle_remote_preset(params, ctx_arg.ex);
 
@@ -570,7 +572,7 @@ static bool common_params_parse_ex(int argc, char ** argv, common_params_context
     }
 
     // handle model and download
-    {
+    if (!skip_model_download) {
         auto res = common_params_handle_model(params.model, params.hf_token, params.offline);
         if (params.no_mmproj) {
             params.mmproj = {};
@@ -591,7 +593,7 @@ static bool common_params_parse_ex(int argc, char ** argv, common_params_context
 
     // model is required (except for server)
     // TODO @ngxson : maybe show a list of available models in CLI in this case
-    if (params.model.path.empty() && ctx_arg.ex != LLAMA_EXAMPLE_SERVER && !params.usage && !params.completion) {
+    if (params.model.path.empty() && ctx_arg.ex != LLAMA_EXAMPLE_SERVER && !skip_model_download && !params.usage && !params.completion) {
         throw std::invalid_argument("error: --model is required\n");
     }
 

common/common.cpp

@@ -1442,6 +1442,7 @@ struct llama_model_params common_model_params_to_llama(common_params & params) {
 
     mparams.progress_callback           = params.load_progress_callback;
     mparams.progress_callback_user_data = params.load_progress_callback_user_data;
+    mparams.no_alloc                    = params.no_alloc;
 
     return mparams;
 }

common/common.h

@@ -679,6 +679,7 @@ struct common_params {
     // return false from callback to abort model loading or true to continue
     llama_progress_callback load_progress_callback = NULL;
     void *                  load_progress_callback_user_data = NULL;
+    bool no_alloc = false; // Don't allocate model buffers
 };
 
 // call once at the start of a program if it uses libcommon