[FIX] Catch syntax error of Regex Guide to avoid crash (#1521)

python/sglang/srt/constrained/fsm_cache.py

@@ -14,13 +14,17 @@ limitations under the License.
 """
 
 """Cache for the compressed finite state machine."""
+import logging
 
+from interegular import InvalidSyntax, parse_pattern
 from outlines.fsm.json_schema import build_regex_from_schema
 from transformers import AutoTokenizer
 
 from sglang.srt.constrained import RegexGuide, TransformerTokenizer
 from sglang.srt.constrained.base_tool_cache import BaseToolCache
 
+logger = logging.getLogger(__name__)
+
 
 class FSMCache(BaseToolCache):
     def __init__(
@@ -76,5 +80,9 @@ class FSMCache(BaseToolCache):
             regex = key_string
         else:
             raise ValueError(f"Invalid key_type: {key_type}")
-
+        try:
+            parse_pattern(regex)
+        except InvalidSyntax as e:
+            logger.warning(f"skip invalid regex guide: {regex=}, {e=}")
+            return None, regex
         return RegexGuide(regex, self.outlines_tokenizer), regex

python/sglang/srt/constrained/jump_forward.py

@@ -19,10 +19,12 @@ Reference: https://lmsys.org/blog/2024-02-05-compressed-fsm/
 """
 
 import dataclasses
+import logging
 from collections import defaultdict
 
 import interegular
 import outlines.caching
+from interegular import InvalidSyntax
 
 from sglang.srt.constrained import (
     FSMInfo,
@@ -34,6 +36,8 @@ from sglang.srt.constrained.base_tool_cache import BaseToolCache
 
 IP_REGEX = r"((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)"
 
+logger = logging.getLogger(__name__)
+
 
 @dataclasses.dataclass
 class JumpEdge:
@@ -47,7 +51,12 @@ class JumpForwardMap:
     def __init__(self, regex_string):
         @disk_cache()
         def _init_state_to_jump_forward(regex_string):
-            regex_pattern = interegular.parse_pattern(regex_string)
+            try:
+                regex_pattern = interegular.parse_pattern(regex_string)
+            except InvalidSyntax as e:
+                logger.warning(f"skip invalid regex: {regex_string}, {e=}")
+                self.state_to_jump_forward = None
+                return
 
             byte_fsm = make_byte_level_fsm(
                 regex_pattern.to_fsm().reduce(), keep_utf8=True
@@ -165,7 +174,11 @@ class JumpForwardCache(BaseToolCache):
         super().__init__()
 
     def init_value(self, regex):
-        return JumpForwardMap(regex)
+        forward_map = JumpForwardMap(regex)
+        if forward_map.state_to_jump_forward:
+            return forward_map
+        else:
+            return None
 
 
 def test_main(regex_string):