hermes-agent/tests/cli/test_surrogate_sanitization.py
Teknium 2ff1ef6ae6
fix(surrogates): sanitize reasoning/reasoning_content/reasoning_details fields (#11628)
Byte-level reasoning models (xiaomi/mimo-v2-pro, kimi, glm) can emit lone
surrogates in reasoning output. The proactive sanitizer walked content/
name/tool_calls but not extra fields like reasoning or the nested
reasoning_details array. Surrogates in those fields survived the
proactive pass, crashed json.dumps() in the OpenAI SDK, and the recovery
block's _sanitize_messages_surrogates(messages) call also didn't check
those fields — so 'found' was False, no retry happened, and after 3
attempts the user saw:

  API call failed after 3 retries. 'utf-8' codec can't encode characters
  in position N-M: surrogates not allowed

Changes:
- _sanitize_messages_surrogates: walk any extra string fields (reasoning,
  reasoning_content, etc.) and recurse into nested dict/list values
  (reasoning_details). Mirrors _sanitize_messages_non_ascii coverage
  added in PR #10537.
- _sanitize_structure_surrogates: new recursive walker, mirror of
  _sanitize_structure_non_ascii but for surrogate recovery.
- UnicodeEncodeError recovery block: also sanitize api_messages,
  api_kwargs, and prefill_messages (not just the canonical messages
  list — the API-copy carries reasoning_content transformed from
  reasoning and that's what the SDK actually serializes). Always
  retry on detected surrogate errors, not only when we found
  something to strip — gate on error type per PR #10537's pattern.

Tests: extended tests/cli/test_surrogate_sanitization.py with
coverage for reasoning, reasoning_content, reasoning_details (flat
and deeply nested), structure walker, and an integration case that
reproduces the exact api_messages shape that was crashing.
2026-04-17 13:30:47 -07:00

336 lines
13 KiB
Python

"""Tests for surrogate character sanitization in user input.
Surrogates (U+D800..U+DFFF) are invalid in UTF-8 and crash json.dumps()
inside the OpenAI SDK. They can appear via clipboard paste from rich-text
editors like Google Docs, OR from byte-level reasoning models (xiaomi/mimo,
kimi, glm) emitting lone halves in reasoning output.
"""
import json
import pytest
from unittest.mock import MagicMock, patch
from run_agent import (
_sanitize_surrogates,
_sanitize_messages_surrogates,
_sanitize_structure_surrogates,
_SURROGATE_RE,
)
class TestSanitizeSurrogates:
"""Test the _sanitize_surrogates() helper."""
def test_normal_text_unchanged(self):
text = "Hello, this is normal text with unicode: café ñ 日本語 🎉"
assert _sanitize_surrogates(text) == text
def test_empty_string(self):
assert _sanitize_surrogates("") == ""
def test_single_surrogate_replaced(self):
result = _sanitize_surrogates("Hello \udce2 world")
assert result == "Hello \ufffd world"
def test_multiple_surrogates_replaced(self):
result = _sanitize_surrogates("a\ud800b\udc00c\udfff")
assert result == "a\ufffdb\ufffdc\ufffd"
def test_all_surrogate_range(self):
"""Verify the regex catches the full surrogate range."""
for cp in [0xD800, 0xD900, 0xDA00, 0xDB00, 0xDC00, 0xDD00, 0xDE00, 0xDF00, 0xDFFF]:
text = f"test{chr(cp)}end"
result = _sanitize_surrogates(text)
assert '\ufffd' in result, f"Surrogate U+{cp:04X} not caught"
def test_result_is_json_serializable(self):
"""Sanitized text must survive json.dumps + utf-8 encoding."""
dirty = "data \udce2\udcb0 from clipboard"
clean = _sanitize_surrogates(dirty)
serialized = json.dumps({"content": clean}, ensure_ascii=False)
# Must not raise UnicodeEncodeError
serialized.encode("utf-8")
def test_original_surrogates_fail_encoding(self):
"""Confirm the original bug: surrogates crash utf-8 encoding."""
dirty = "data \udce2 from clipboard"
serialized = json.dumps({"content": dirty}, ensure_ascii=False)
with pytest.raises(UnicodeEncodeError):
serialized.encode("utf-8")
class TestSanitizeMessagesSurrogates:
"""Test the _sanitize_messages_surrogates() helper for message lists."""
def test_clean_messages_returns_false(self):
msgs = [
{"role": "user", "content": "all clean"},
{"role": "assistant", "content": "me too"},
]
assert _sanitize_messages_surrogates(msgs) is False
def test_dirty_string_content_sanitized(self):
msgs = [
{"role": "user", "content": "text with \udce2 surrogate"},
]
assert _sanitize_messages_surrogates(msgs) is True
assert "\ufffd" in msgs[0]["content"]
assert "\udce2" not in msgs[0]["content"]
def test_dirty_multimodal_content_sanitized(self):
msgs = [
{"role": "user", "content": [
{"type": "text", "text": "multimodal \udce2 content"},
{"type": "image_url", "image_url": {"url": "http://example.com"}},
]},
]
assert _sanitize_messages_surrogates(msgs) is True
assert "\ufffd" in msgs[0]["content"][0]["text"]
assert "\udce2" not in msgs[0]["content"][0]["text"]
def test_mixed_clean_and_dirty(self):
msgs = [
{"role": "user", "content": "clean text"},
{"role": "user", "content": "dirty \udce2 text"},
{"role": "assistant", "content": "clean response"},
]
assert _sanitize_messages_surrogates(msgs) is True
assert msgs[0]["content"] == "clean text"
assert "\ufffd" in msgs[1]["content"]
assert msgs[2]["content"] == "clean response"
def test_non_dict_items_skipped(self):
msgs = ["not a dict", {"role": "user", "content": "ok"}]
assert _sanitize_messages_surrogates(msgs) is False
def test_tool_messages_sanitized(self):
"""Tool results could also contain surrogates from file reads etc."""
msgs = [
{"role": "tool", "content": "result with \udce2 data", "tool_call_id": "x"},
]
assert _sanitize_messages_surrogates(msgs) is True
assert "\ufffd" in msgs[0]["content"]
class TestReasoningFieldSurrogates:
"""Surrogates in reasoning fields (byte-level reasoning models).
xiaomi/mimo, kimi, glm and similar byte-level tokenizers can emit lone
surrogates in reasoning output. These fields are carried through to the
API as `reasoning_content` on assistant messages, and must be sanitized
or json.dumps() crashes with 'utf-8' codec can't encode surrogates.
"""
def test_reasoning_field_sanitized(self):
msgs = [
{"role": "assistant", "content": "ok", "reasoning": "thought \udce2 here"},
]
assert _sanitize_messages_surrogates(msgs) is True
assert "\udce2" not in msgs[0]["reasoning"]
assert "\ufffd" in msgs[0]["reasoning"]
def test_reasoning_content_field_sanitized(self):
"""api_messages carry `reasoning_content` built from `reasoning`."""
msgs = [
{"role": "assistant", "content": "ok", "reasoning_content": "thought \udce2 here"},
]
assert _sanitize_messages_surrogates(msgs) is True
assert "\udce2" not in msgs[0]["reasoning_content"]
assert "\ufffd" in msgs[0]["reasoning_content"]
def test_reasoning_details_nested_sanitized(self):
"""reasoning_details is a list of dicts with nested string fields."""
msgs = [
{
"role": "assistant",
"content": "ok",
"reasoning_details": [
{"type": "reasoning.summary", "summary": "summary \udce2 text"},
{"type": "reasoning.text", "text": "chain \udc00 of thought"},
],
},
]
assert _sanitize_messages_surrogates(msgs) is True
assert "\udce2" not in msgs[0]["reasoning_details"][0]["summary"]
assert "\ufffd" in msgs[0]["reasoning_details"][0]["summary"]
assert "\udc00" not in msgs[0]["reasoning_details"][1]["text"]
assert "\ufffd" in msgs[0]["reasoning_details"][1]["text"]
def test_deeply_nested_reasoning_sanitized(self):
"""Nested dicts / lists inside extra fields are recursed into."""
msgs = [
{
"role": "assistant",
"content": "ok",
"reasoning_details": [
{
"type": "reasoning.encrypted",
"content": {
"encrypted_content": "opaque",
"text_parts": ["part1", "part2 \udce2 part"],
},
},
],
},
]
assert _sanitize_messages_surrogates(msgs) is True
assert (
msgs[0]["reasoning_details"][0]["content"]["text_parts"][1]
== "part2 \ufffd part"
)
def test_reasoning_end_to_end_json_serialization(self):
"""After sanitization, the full message dict must serialize clean."""
msgs = [
{
"role": "assistant",
"content": "answer",
"reasoning_content": "reasoning with \udce2 surrogate",
"reasoning_details": [
{"summary": "nested \udcb0 surrogate"},
],
},
]
_sanitize_messages_surrogates(msgs)
# Must round-trip through json + utf-8 encoding without error
payload = json.dumps(msgs, ensure_ascii=False).encode("utf-8")
assert b"\\" not in payload[:0] # sanity — just ensure we got bytes
assert len(payload) > 0
def test_no_surrogates_returns_false(self):
"""Clean reasoning fields don't trigger a modification."""
msgs = [
{
"role": "assistant",
"content": "ok",
"reasoning": "clean thought",
"reasoning_content": "also clean",
"reasoning_details": [{"summary": "clean summary"}],
},
]
assert _sanitize_messages_surrogates(msgs) is False
class TestSanitizeStructureSurrogates:
"""Test the _sanitize_structure_surrogates() helper for nested payloads."""
def test_empty_payload(self):
assert _sanitize_structure_surrogates({}) is False
assert _sanitize_structure_surrogates([]) is False
def test_flat_dict(self):
payload = {"a": "clean", "b": "dirty \udce2 text"}
assert _sanitize_structure_surrogates(payload) is True
assert payload["a"] == "clean"
assert "\ufffd" in payload["b"]
def test_flat_list(self):
payload = ["clean", "dirty \udce2"]
assert _sanitize_structure_surrogates(payload) is True
assert payload[0] == "clean"
assert "\ufffd" in payload[1]
def test_nested_dict_in_list(self):
payload = [{"x": "dirty \udce2"}, {"x": "clean"}]
assert _sanitize_structure_surrogates(payload) is True
assert "\ufffd" in payload[0]["x"]
assert payload[1]["x"] == "clean"
def test_deeply_nested(self):
payload = {
"level1": {
"level2": [
{"level3": "deep \udce2 surrogate"},
],
},
}
assert _sanitize_structure_surrogates(payload) is True
assert "\ufffd" in payload["level1"]["level2"][0]["level3"]
def test_clean_payload_returns_false(self):
payload = {"a": "clean", "b": [{"c": "also clean"}]}
assert _sanitize_structure_surrogates(payload) is False
def test_non_string_values_ignored(self):
payload = {"int": 42, "list": [1, 2, 3], "dict": {"none": None}, "bool": True}
assert _sanitize_structure_surrogates(payload) is False
# Non-string values survive unchanged
assert payload["int"] == 42
assert payload["list"] == [1, 2, 3]
class TestApiMessagesSurrogateRecovery:
"""Integration: verify the recovery block sanitizes api_messages.
The bug this guards against: a surrogate in `reasoning_content` on
api_messages (transformed from `reasoning` during build) crashes the
OpenAI SDK's json.dumps(), and the recovery block previously only
sanitized the canonical `messages` list — not `api_messages` — so the
next retry would send the same broken payload and fail 3 times.
"""
def test_api_messages_reasoning_content_sanitized(self):
"""The extended sanitizer catches reasoning_content in api_messages."""
api_messages = [
{"role": "system", "content": "sys"},
{
"role": "assistant",
"content": "response",
"reasoning_content": "thought \udce2 trail",
"tool_calls": [
{
"id": "call_1",
"function": {"name": "tool", "arguments": "{}"},
}
],
},
{"role": "tool", "content": "result", "tool_call_id": "call_1"},
]
assert _sanitize_messages_surrogates(api_messages) is True
assert "\udce2" not in api_messages[1]["reasoning_content"]
# Full payload must now serialize clean
json.dumps(api_messages, ensure_ascii=False).encode("utf-8")
class TestRunConversationSurrogateSanitization:
"""Integration: verify run_conversation sanitizes user_message."""
@patch("run_agent.AIAgent._build_system_prompt")
@patch("run_agent.AIAgent._interruptible_streaming_api_call")
@patch("run_agent.AIAgent._interruptible_api_call")
def test_user_message_surrogates_sanitized(self, mock_api, mock_stream, mock_sys):
"""Surrogates in user_message are stripped before API call."""
from run_agent import AIAgent
mock_sys.return_value = "system prompt"
# Mock streaming to return a simple response
mock_choice = MagicMock()
mock_choice.message.content = "response"
mock_choice.message.tool_calls = None
mock_choice.message.refusal = None
mock_choice.finish_reason = "stop"
mock_choice.message.reasoning_content = None
mock_response = MagicMock()
mock_response.choices = [mock_choice]
mock_response.usage = MagicMock(prompt_tokens=10, completion_tokens=5, total_tokens=15)
mock_response.model = "test-model"
mock_response.id = "test-id"
mock_stream.return_value = mock_response
mock_api.return_value = mock_response
agent = AIAgent(model="test/model", api_key="test-key", base_url="http://localhost:1234/v1", quiet_mode=True, skip_memory=True, skip_context_files=True)
agent.client = MagicMock()
# Pass a message with surrogates
result = agent.run_conversation(
user_message="test \udce2 message",
conversation_history=[],
)
# The message stored in history should have surrogates replaced
for msg in result.get("messages", []):
if msg.get("role") == "user":
assert "\udce2" not in msg["content"], "Surrogate leaked into stored message"
assert "\ufffd" in msg["content"], "Replacement char not in stored message"