Flip dumper to disable by default and refactor environment handling (#18878)

python/sglang/srt/environ.py

@@ -7,11 +7,17 @@ from typing import Any
 
 
 @contextmanager
-def temp_set_env(**env_vars: dict[str, Any]):
-    """Temporarily set non-sglang environment variables, e.g. OPENAI_API_KEY"""
-    for key in env_vars:
-        if key.startswith("SGLANG_") or key.startswith("SGL_"):
-            raise ValueError("temp_set_env should not be used for sglang env vars")
+def temp_set_env(*, allow_sglang: bool = False, **env_vars: Any):
+    """Temporarily set environment variables, restoring originals on exit.
+
+    By default, SGLANG_*/SGL_* keys are rejected — use ``Envs`` descriptors
+    for those.  Pass ``allow_sglang=True`` only for special env vars that
+    intentionally bypass ``environ.py`` (e.g. ``SGLANG_DUMPER_*``).
+    """
+    if not allow_sglang:
+        for key in env_vars:
+            if key.startswith("SGLANG_") or key.startswith("SGL_"):
+                raise ValueError("temp_set_env should not be used for sglang env vars")
 
     backup = {key: os.environ.get(key) for key in env_vars}
     try: