feat: drop python 3.8 support

Author: pwwang

pyproject.toml

@@ -11,7 +11,7 @@ authors = [
 ]
 license = {text = "MIT"}
 readme = "README.md"
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
     "executing>=2.1",
     "typing_extensions>=4.13; python_version < '3.10'",
@@ -29,7 +29,7 @@ dev = [
     "pytest>=8",
     "pytest-cov>=5",
     "coverage[toml]>=7",
-    "ipykernel>=6.29.5",
+    "ipykernel>=6",
     "flake8>=5.0.4",
     "mypy>=1.14.1",
 ]
@@ -54,5 +54,5 @@ strict_optional = false
 
 [tool.black]
 line-length = 88
-target-version = ['py38', 'py39', 'py310', 'py311', 'py312', 'py313']
+target-version = ['py39', 'py310', 'py311', 'py312', 'py313']
 include = '\.pyi?$'

uv.lock

@@ -108,12 +108,8 @@
 ArgSourceType: TypeAlias = Union[ArgSourceType, Tuple[ArgSourceType, ...]]
 ArgSourceType: TypeAlias = Union[ArgSourceType, Mapping[str, ArgSourceType]]
 
-if sys.version_info >= (3, 8):
-    ASSIGN_TYPES = (ast.Assign, ast.AnnAssign, ast.NamedExpr)
-    AssignType: TypeAlias = Union[ASSIGN_TYPES]  # type: ignore
-else:  # pragma: no cover  # Python < 3.8
-    ASSIGN_TYPES = (ast.Assign, ast.AnnAssign)
-    AssignType: TypeAlias = Union[ASSIGN_TYPES]  # type: ignore
+ASSIGN_TYPES = (ast.Assign, ast.AnnAssign)
+AssignType: TypeAlias = Union[ASSIGN_TYPES]  # type: ignore
 
 PY311 = sys.version_info >= (3, 11)
 MODULE_IGNORE_ID_NAME = "__varname_ignore_id__"