perf(logging): skip escaping plain request text and walk each request value once

A redacted failure built JSON and repr copies of every request text for each
error field, though printable ASCII without a double quote or backslash escapes
to itself, and walked the original messages a second time. The scrubbed output
is unchanged.

litellm/litellm_core_utils/redact_messages.py

@@ -448,6 +448,7 @@ def _redacted_responses_api_response(
 _REQUEST_TEXT_KEYS: Final = ("messages", "input", "prompt", "system", "instructions")
 _STRUCTURAL_KEYS: Final = frozenset({"role", "type", "id", "tool_call_id", "name"})
 _MIN_UNQUOTED_TEXT_LENGTH: Final = 4
+_ESCAPED_CHARACTERS: Final = ('"', "\\")
 # pydantic shows a long input value as its repr's first 25 and last 24 characters around "...", quotes and
 # container keys included, so each side of the cut shows at most 24 characters of a quoted text
 _CUT_SIDE_LENGTH: Final = 24
@@ -473,9 +474,12 @@ def _next_level(level: tuple[object, ...], _: None) -> tuple[object, ...]:
 def request_texts(*values: object) -> frozenset[str]:
     """
     The non-empty strings a request carries under ``values``, skipping structural fields such as ``role``
-    and ``type``.
+    and ``type``. A value passed more than once is walked once.
     """
-    levels: Final = itertools.takewhile(bool, itertools.accumulate(itertools.repeat(None), _next_level, initial=values))
+    distinct_values: Final = tuple({id(value): value for value in values}.values())
+    levels: Final = itertools.takewhile(
+        bool, itertools.accumulate(itertools.repeat(None), _next_level, initial=distinct_values)
+    )
     return frozenset(value for value in itertools.chain.from_iterable(levels) if isinstance(value, str) and value)
 
 
@@ -490,7 +494,10 @@ def failure_request_texts(model_call_details: Mapping[str, object], *originals:
 
 
 def _echo_forms(text: str) -> frozenset[str]:
-    """How an error can quote ``text``: verbatim, or JSON or repr escaped."""
+    """How an error can quote ``text``: verbatim, or JSON or repr escaped. Printable ASCII without a double quote
+    or a backslash escapes to itself."""
+    if text.isascii() and text.isprintable() and not any(character in text for character in _ESCAPED_CHARACTERS):
+        return frozenset((text,))
     return frozenset({text, json.dumps(text)[1:-1], json.dumps(text, ensure_ascii=False)[1:-1], repr(text)[1:-1]})
 
 

tests/unit/litellm_core_utils/test_redact_messages.py

@@ -12,7 +12,7 @@ import json
 import os
 import threading
 import tracemalloc
-from collections.abc import AsyncIterator, Mapping
+from collections.abc import AsyncIterator, Callable, Mapping
 from datetime import datetime
 from types import MappingProxyType, SimpleNamespace
 from typing import Final, Optional, Union
@@ -2101,6 +2101,20 @@ def test_scrub_request_text_replaces_each_way_an_error_quotes_the_prompt(quoted:
     assert scrubbed.startswith("Invalid content: <") and scrubbed.endswith("> rejected")
 
 
+@pytest.mark.parametrize(
+    "prompt",
+    ['say "hi" to Bob', "C:\\Users\\bob", "café for Bob", "tab\tfor Bob"],
+    ids=["double_quote", "backslash", "non_ascii", "control_character"],
+)
+@pytest.mark.parametrize("escaped", [json.dumps, repr], ids=["json", "repr"])
+def test_scrub_request_text_replaces_an_escaped_echo_of_a_prompt_that_escaping_changes(
+    prompt: str, escaped: Callable[[str], str]
+) -> None:
+    error: Final = f"Invalid content: <{escaped(prompt)[1:-1]}> rejected"
+
+    assert scrub_request_text(error, request_texts(prompt)) == "Invalid content: <redacted-by-litellm> rejected"
+
+
 @pytest.mark.parametrize(
     "value",
     [PROMPT, [PROMPT], {"content": PROMPT}, [{"content": PROMPT}], [{"content": LONG_PROMPT}], [LONG_PROMPT]],