Turn @config into a dataclass_transform (#31541)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/engine/test_arg_utils.py

@@ -3,11 +3,11 @@
 
 import json
 from argparse import ArgumentError
-from contextlib import nullcontext
-from dataclasses import dataclass, field
+from contextlib import AbstractContextManager, nullcontext
 from typing import Annotated, Literal
 
 import pytest
+from pydantic import Field
 
 from vllm.config import AttentionConfig, CompilationConfig, config
 from vllm.engine.arg_utils import (
@@ -96,7 +96,7 @@ def test_get_type(type_hints, type, expected):
     ],
 )
 def test_literal_to_kwargs(type_hints, expected):
-    context = nullcontext()
+    context: AbstractContextManager[object] = nullcontext()
     if expected is Exception:
         context = pytest.raises(expected)
     with context:
@@ -104,14 +104,12 @@ def test_literal_to_kwargs(type_hints, expected):
 
 
 @config
-@dataclass
 class NestedConfig:
     field: int = 1
     """field"""
 
 
 @config
-@dataclass
 class DummyConfig:
     regular_bool: bool = True
     """Regular bool with default True"""
@@ -119,23 +117,23 @@ class DummyConfig:
     """Optional bool with default None"""
     optional_literal: Literal["x", "y"] | None = None
     """Optional literal with default None"""
-    tuple_n: tuple[int, ...] = field(default_factory=lambda: (1, 2, 3))
+    tuple_n: tuple[int, ...] = Field(default_factory=lambda: (1, 2, 3))
     """Tuple with variable length"""
-    tuple_2: tuple[int, int] = field(default_factory=lambda: (1, 2))
+    tuple_2: tuple[int, int] = Field(default_factory=lambda: (1, 2))
     """Tuple with fixed length"""
-    list_n: list[int] = field(default_factory=lambda: [1, 2, 3])
+    list_n: list[int] = Field(default_factory=lambda: [1, 2, 3])
     """List with variable length"""
-    list_literal: list[Literal[1, 2]] = field(default_factory=list)
+    list_literal: list[Literal[1, 2]] = Field(default_factory=list)
     """List with literal choices"""
-    list_union: list[str | type[object]] = field(default_factory=list)
+    list_union: list[str | type[object]] = Field(default_factory=list)
     """List with union type"""
-    set_n: set[int] = field(default_factory=lambda: {1, 2, 3})
+    set_n: set[int] = Field(default_factory=lambda: {1, 2, 3})
     """Set with variable length"""
     literal_literal: Literal[Literal[1], Literal[2]] = 1
     """Literal of literals with default 1"""
-    json_tip: dict = field(default_factory=dict)
+    json_tip: dict = Field(default_factory=dict)
     """Dict which will be JSON in CLI"""
-    nested_config: NestedConfig = field(default_factory=NestedConfig)
+    nested_config: NestedConfig = Field(default_factory=NestedConfig)
     """Nested config"""
 
 
@@ -195,7 +193,7 @@ def test_get_kwargs():
     json_tip = "Should either be a valid JSON string or JSON keys"
     assert json_tip in kwargs["json_tip"]["help"]
     # nested config should construct the nested config
-    assert kwargs["nested_config"]["type"]('{"field": 2}') == NestedConfig(2)
+    assert kwargs["nested_config"]["type"]('{"field": 2}') == NestedConfig(2)  # type: ignore[call-arg]
 
 
 @pytest.mark.parametrize(