Commit 4c4ca5b18 for llama.cpp

commit 4c4ca5b18854c973655a62a6164a3ae930ee76b0
Author: Georgi Gerganov <ggerganov@gmail.com>
Date:   Wed Nov 4 10:32:45 2026 +0200

    common : do not allow `_` in sidecar (#31639)

diff --git a/common/download.cpp b/common/download.cpp
index 4de93f30d..979dd6326 100644
--- a/common/download.cpp
+++ b/common/download.cpp
@@ -749,7 +749,7 @@ static hf_cache::hf_file find_best_model(const hf_cache::hf_files & files,

     for (const auto & t : tags) {
         // match the tag as a full token, so ":F16" does not match a BF16 file
-        std::regex pattern("(^|[-./_])" + t + "[.-]", std::regex::icase);
+        std::regex pattern("(^|[-./])" + t + "[.-]", std::regex::icase);
         for (const auto & f : files) {
             if (gguf_filename_is_model(f.path) &&
                 std::regex_search(f.path, pattern)) {
diff --git a/tests/test-model-resolution.cpp b/tests/test-model-resolution.cpp
index 73a87482d..e2576a1c9 100644
--- a/tests/test-model-resolution.cpp
+++ b/tests/test-model-resolution.cpp
@@ -161,12 +161,6 @@ static const std::vector<std::string> twins = {
     "model-Q4_XS.gguf",
 };

-// an underscore separates the quant like a dash, as in step3p5_flash_Q4_K_S.gguf
-static const std::vector<std::string> underscore = {
-    "model_Q4_K_S.gguf",
-    "model_Q8_0.gguf",
-};
-
 // every speculative sidecar type at the same quant
 static const std::vector<std::string> quad = {
     "model-Q8_0.gguf",
@@ -301,15 +295,6 @@ static const plan_case plan_cases[] = {
      "model-IQ4_XS.gguf", {"model-IQ4_XS.gguf"},
      "", "", "", "", ""},

-    // the token boundary accepts an underscore, for the tag and the default lookup
-    {"underscore tag", underscore, "test/repo:Q4_K_S", "", false, false,
-     "model_Q4_K_S.gguf", {"model_Q4_K_S.gguf"},
-     "", "", "", "", ""},
-
-    {"underscore default", underscore, "test/repo", "", false, false,
-     "model_Q8_0.gguf", {"model_Q8_0.gguf"},
-     "", "", "", "", ""},
-
     // every sidecar type resolves at the tag
     {"quad exact tag", quad, "test/repo:Q8_0", "", true, false,
      "model-Q8_0.gguf", {"model-Q8_0.gguf"},