fix: DSML token leakage in DeepSeek-V4 and 3.2 (#1647)

Signed-off-by: AlpinDale <alpindale@gmail.com>

Author: AlpinDale

aphrodite/tool_parsers/deepseekv32_tool_parser.py

@@ -26,6 +26,7 @@
     Tool,
     ToolParser,
 )
+from aphrodite.tool_parsers.utils import partial_tag_overlap
 
 logger = init_logger(__name__)
 
@@ -54,8 +55,8 @@ def __init__(self, tokenizer: TokenizerLike, tools: list[Tool] | None = None):
         self.tool_call_start_token: str = "<｜DSML｜function_calls>"
 
         # Streaming state
-        self.is_tool_call_started: bool = False
         self.current_tool_index: int = 0
+        self._sent_content_idx: int = 0
 
         # Regex patterns for complete parsing
         self.tool_call_complete_regex = re.compile(r"<｜DSML｜function_calls>(.*?)</｜DSML｜function_calls>", re.DOTALL)
@@ -202,7 +203,7 @@ def extract_tool_calls(
     def _reset_streaming_state(self):
         """Reset all streaming state."""
         self.current_tool_index = 0
-        self.is_tool_call_started = False
+        self._sent_content_idx = 0
         self.prev_tool_call_arr.clear()
         self.streamed_args_for_tool.clear()
 
@@ -245,6 +246,24 @@ def _extract_delta_tool_calls(
 
         return delta_tool_calls
 
+    def _extract_content(self, current_text: str) -> str | None:
+        """Return unsent non-tool-call text, or None.
+
+        Holds back any suffix that could be a partial start marker
+        so that split markers are never leaked as content.
+        """
+        if self.tool_call_start_token not in current_text:
+            overlap = partial_tag_overlap(current_text, self.tool_call_start_token)
+            sendable_idx = len(current_text) - overlap
+        else:
+            sendable_idx = current_text.index(self.tool_call_start_token)
+
+        if sendable_idx > self._sent_content_idx:
+            content = current_text[self._sent_content_idx : sendable_idx]
+            self._sent_content_idx = sendable_idx
+            return content
+        return None
+
     def extract_tool_calls_streaming(
         self,
         previous_text: str,
@@ -266,29 +285,11 @@ def extract_tool_calls_streaming(
         if not previous_text:
             self._reset_streaming_state()
 
-        # Detect whether we've entered the tool-call region.
-        # Use current_text (not delta_text) since the start token may
-        # be split across chunks.
-        content_before = None
-        if self.is_tool_call_started:
-            pass
-        elif self.tool_call_start_token in current_text:
-            # Tool-call region found, capture any plain text before it.
-            self.is_tool_call_started = True
-            start_idx = current_text.index(self.tool_call_start_token)
-            content_before = current_text[len(previous_text) : start_idx] or None
-        else:
-            # Still in plain-text region, forward as content.
-            return DeltaMessage(content=delta_text) if delta_text else None
-
-        # Inside tool-call region: emit any newly completed invokes.
+        content = self._extract_content(current_text)
         delta_tool_calls = self._extract_delta_tool_calls(current_text, request)
 
-        if delta_tool_calls or content_before:
-            return DeltaMessage(
-                content=content_before,
-                tool_calls=delta_tool_calls,
-            )
+        if delta_tool_calls or content:
+            return DeltaMessage(content=content, tool_calls=delta_tool_calls)
 
         # Empty delta with token ids means EOS or closing tag; return
         # non-None so the serving framework can finalize finish_reason.