Build Rust extensions on demand in source checkouts (#34994)

scripts/ci/cuda/ci_install_dependency.sh

@@ -460,7 +460,7 @@ require_prebuilt_rust_exts() {
         return
     fi
 
-    # Exact EXT_SUFFIX rather than a _core*.so glob: no crate sets abi3, so a module
+    # Exact EXT_SUFFIX rather than an _*.so glob: no crate sets abi3, so a module
     # built for another minor version satisfies the glob while the import system
     # ignores it, leaving is_rust_server_built() false and the Rust-server tests
     # silently skipped. Stages have no setup-python, so the interpreter is whatever
@@ -469,13 +469,13 @@ require_prebuilt_rust_exts() {
     local suffix
     suffix=$(python3 -c 'import sysconfig; print(sysconfig.get_config_var("EXT_SUFFIX"))')
     local missing=()
-    local pkg
-    for pkg in server grpc multimodal; do
-        [ -f "python/sglang/srt/${pkg}/_core${suffix}" ] || missing+=("${pkg}")
+    local module
+    for module in server grpc multimodal; do
+        [ -f "python/sglang/srt/rust_extensions/_${module}${suffix}" ] || missing+=("${module}")
     done
     if [ ${#missing[@]} -gt 0 ]; then
-        echo "::warning::no prebuilt _core${suffix} for: ${missing[*]}; building from source"
-        ls -l python/sglang/srt/*/_core*.so 2>/dev/null || echo "(no extension modules at all)"
+        echo "::warning::no prebuilt Rust extension ${suffix} for: ${missing[*]}; building from source"
+        ls -l python/sglang/srt/rust_extensions/_*.so 2>/dev/null || echo "(no extension modules at all)"
         export SGLANG_BUILD_RUST_EXTS=
         mark_step_done "${FUNCNAME[0]}"
         return
@@ -812,7 +812,7 @@ print(f"sglang resolves to {spec.origin}")
 # so a .so that cannot load passes find_spec and only fails inside some suite.
 import importlib
 for mod in ("server", "grpc", "multimodal"):
-    name = f"sglang.srt.{mod}._core"
+    name = f"sglang.srt.rust_extensions._{mod}"
     try:
         importlib.import_module(name)
     except Exception as exc: