[Bugfix] Remove unsupported comma-separated detailed trace values (#55702)

Signed-off-by: git-jxj <65210887+git-jxj@users.noreply.github.com>
Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

vllm/config/observability.py

@@ -2,7 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from functools import cached_property
-from typing import Any, Literal, cast
+from typing import Any, Literal
 
 from packaging.version import parse
 from pydantic import Field, field_validator, model_validator
@@ -150,17 +150,6 @@ class ObservabilityConfig:
                 )
         return value
 
-    @field_validator("collect_detailed_traces")
-    @classmethod
-    def _validate_collect_detailed_traces(
-        cls, value: list[DetailedTraceModules] | None
-    ) -> list[DetailedTraceModules] | None:
-        """Handle the legacy case where users might provide a comma-separated
-        string instead of a list of strings."""
-        if value is not None and len(value) == 1 and "," in value[0]:
-            value = cast(list[DetailedTraceModules], value[0].split(","))
-        return value
-
     @model_validator(mode="after")
     def _validate_tracing_config(self):
         if self.collect_detailed_traces and not self.otlp_traces_endpoint:

vllm/engine/arg_utils.py

@@ -10,7 +10,6 @@ import os
 import sys
 from collections.abc import Callable
 from dataclasses import MISSING, asdict, dataclass, fields, is_dataclass
-from itertools import permutations
 from types import UnionType
 from typing import (
     TYPE_CHECKING,
@@ -1523,13 +1522,6 @@ class EngineArgs:
         observability_group.add_argument(
             "--otlp-traces-endpoint", **observability_kwargs["otlp_traces_endpoint"]
         )
-        # TODO: generalise this special case
-        choices = observability_kwargs["collect_detailed_traces"]["choices"]
-        metavar = f"{{{','.join(str(c) for c in choices)}}}"
-        observability_kwargs["collect_detailed_traces"]["metavar"] = metavar
-        observability_kwargs["collect_detailed_traces"]["choices"] += [
-            ",".join(p) for p in permutations(get_args(DetailedTraceModules), r=2)
-        ]
         observability_group.add_argument(
             "--collect-detailed-traces",
             **observability_kwargs["collect_detailed_traces"],