Merge branch 'upstream' into concedo_experimental

# Conflicts:
#	.github/workflows/build.yml
#	.github/workflows/server.yml
#	CMakeLists.txt
#	Makefile
#	README.md
#	ci/run.sh
#	common/CMakeLists.txt
#	common/common.cpp
#	docs/backend/SYCL.md
#	examples/embedding/embedding.cpp
#	examples/imatrix/imatrix.cpp
#	examples/infill/infill.cpp
#	examples/llama-bench/llama-bench.cpp
#	examples/main/README.md
#	examples/parallel/parallel.cpp
#	examples/perplexity/perplexity.cpp
#	examples/server/CMakeLists.txt
#	examples/server/README.md
#	examples/server/bench/README.md
#	examples/server/tests/README.md
#	examples/speculative/speculative.cpp
#	flake.lock
#	ggml/CMakeLists.txt
#	ggml/src/CMakeLists.txt
#	grammars/README.md
#	scripts/compare-commits.sh
#	scripts/compare-llama-bench.py
#	tests/CMakeLists.txt

examples/gguf-split/gguf-split.cpp

@@ -153,7 +153,7 @@ static void split_params_parse_ex(int argc, const char ** argv, split_params & p
         throw std::invalid_argument("error: invalid parameter for argument: " + arg);
     }
 
-    if (argc - arg_idx < 2) {
+    if (argc - arg_idx != 2) {
         throw std::invalid_argument("error: bad arguments");
     }
 
@@ -390,10 +390,17 @@ static void gguf_merge(const split_params & split_params) {
     int n_split = 1;
     int total_tensors = 0;
 
-    auto * ctx_out = gguf_init_empty();
+    // avoid overwriting existing output file
+    if (std::ifstream(split_params.output.c_str())) {
+        fprintf(stderr, "%s: output file %s already exists\n", __func__, split_params.output.c_str());
+        exit(EXIT_FAILURE);
+    }
+
     std::ofstream fout(split_params.output.c_str(), std::ios::binary);
     fout.exceptions(std::ofstream::failbit); // fail fast on write errors
 
+    auto * ctx_out = gguf_init_empty();
+
     std::vector<uint8_t> read_data;
     std::vector<ggml_context *> ctx_metas;
     std::vector<gguf_context *> ctx_ggufs;