Use jsonschema to constrain required or specific tool choice (#10550)

python/sglang/srt/function_call/json_array_parser.py

@@ -0,0 +1,63 @@
+import json
+import re
+from typing import List
+
+from sglang.srt.entrypoints.openai.protocol import Tool
+from sglang.srt.function_call.base_format_detector import BaseFormatDetector
+from sglang.srt.function_call.core_types import StreamingParseResult
+
+
+class JsonArrayParser(BaseFormatDetector):
+    """
+    Parser for JSON array tool calls when JSON schema constraints are active.
+
+    This parser is used when tool_choice="required" or a specific tool is named,
+    bypassing model-specific parsers in favor of direct JSON array parsing.
+    """
+
+    def __init__(self):
+        super().__init__()
+        # Configure for JSON array parsing
+        self.bot_token = "["
+        self.eot_token = "]"
+        self.tool_call_separator = ","
+
+    def has_tool_call(self, text: str) -> bool:
+        """
+        Check if the given text contains a JSON tool call (array or single object).
+        """
+        return "[" in text or "{" in text
+
+    def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
+        """
+        Parse JSON tool calls using the base class implementation.
+        """
+        raise NotImplementedError(
+            "Detect and parse not supported for JSON schema constraints."
+        )
+
+    def build_ebnf(self, tools: List[Tool]) -> str:
+        """
+        Build an EBNF grammar for constrained generation.
+        This is not used for JSON schema constraints as they are handled
+        by the constraint backends directly.
+        """
+        raise NotImplementedError(
+            "EBNF generation is not supported for JSON schema constraints."
+        )
+
+    def parse_streaming_increment(
+        self, new_text: str, tools: List[Tool]
+    ) -> StreamingParseResult:
+        """
+        Streaming incremental parsing with tool validation.
+        """
+        return super().parse_streaming_increment(new_text, tools)
+
+    def structure_info(self) -> callable:
+        """
+        Return a function that creates StructureInfo for constrained generation.
+        This is not used for JSON schema constraints as they are handled
+        by the constraint backends directly.
+        """
+        raise NotImplementedError("structure_info not used for JSON schema constraints")