[Refactor] Move sampling tokenizer validation helper (#32694)

python/sglang/srt/sampling/sampling_params.py

@@ -42,36 +42,6 @@ TOP_K_ALL = 1 << 30
 logger = logging.getLogger(__name__)
 
 
-def raise_if_tokenizer_required(
-    tokenizer, stop_strs, stop_regex_strs, min_new_tokens=0
-):
-    """Raise ValueError if tokenizer-dependent features are used without a tokenizer.
-
-    String-based stop conditions (stop_strs, stop_regex_strs) require tokenizer.decode()
-    to convert output token IDs to text for matching. min_new_tokens requires the
-    tokenizer's eos_token_id to penalize. When skip_tokenizer_init=True, these cannot
-    be used.
-    """
-    if tokenizer is not None:
-        return
-
-    if stop_strs:
-        raise ValueError(
-            f"stop={stop_strs!r} is unavailable when skip_tokenizer_init=True "
-            "(requires tokenizer to decode tokens to text for matching)."
-        )
-    if stop_regex_strs:
-        raise ValueError(
-            f"stop_regex={stop_regex_strs!r} is unavailable when skip_tokenizer_init=True "
-            "(requires tokenizer to decode tokens to text for matching)."
-        )
-    if min_new_tokens > 0:
-        raise ValueError(
-            f"min_new_tokens={min_new_tokens} is unavailable when skip_tokenizer_init=True "
-            "(requires tokenizer for eos_token_id)."
-        )
-
-
 class SamplingParams(msgspec.Struct, kw_only=True, array_like=True):
     """
     The sampling parameters.
@@ -321,3 +291,33 @@ def _max_length_from_subpattern(subpattern: sre_parse.SubPattern):
             total += MAX_LEN
 
     return total
+
+
+def raise_if_tokenizer_required(
+    tokenizer, stop_strs, stop_regex_strs, min_new_tokens=0
+):
+    """Raise ValueError if tokenizer-dependent features are used without a tokenizer.
+
+    String-based stop conditions (stop_strs, stop_regex_strs) require tokenizer.decode()
+    to convert output token IDs to text for matching. min_new_tokens requires the
+    tokenizer's eos_token_id to penalize. When skip_tokenizer_init=True, these cannot
+    be used.
+    """
+    if tokenizer is not None:
+        return
+
+    if stop_strs:
+        raise ValueError(
+            f"stop={stop_strs!r} is unavailable when skip_tokenizer_init=True "
+            "(requires tokenizer to decode tokens to text for matching)."
+        )
+    if stop_regex_strs:
+        raise ValueError(
+            f"stop_regex={stop_regex_strs!r} is unavailable when skip_tokenizer_init=True "
+            "(requires tokenizer to decode tokens to text for matching)."
+        )
+    if min_new_tokens > 0:
+        raise ValueError(
+            f"min_new_tokens={min_new_tokens} is unavailable when skip_tokenizer_init=True "
+            "(requires tokenizer for eos_token_id)."
+        )