Fix GitHub CI.

* Add msgspec dep.
* Fix lint issues.
* Massage node.py.
* Change type annotations that aren't compatible with 3.8.

pytype/abstract/_classes.py

@@ -682,7 +682,8 @@ def __hash__(self):
         for name, val in self.formal_type_parameters.items():
           # The 'is not True' check is to prevent us from incorrectly caching
           # the hash when val.resolved == LateAnnotation._RESOLVING.
-          if val.is_late_annotation() and val.resolved is not True:  # pylint: disable=g-bool-id-comparison  # pytype: disable=attribute-error
+          if (val.is_late_annotation() and
+              val.resolved is not True):  # pylint: disable=g-bool-id-comparison  # pytype: disable=attribute-error
             cache = False
           items.append((name, val.full_name))
       hashval = hash((self.base_cls, tuple(items)))

pytype/imports/pickle_utils.py

@@ -29,15 +29,20 @@
 
 import gzip
 import os
+import sys
 from typing import Iterable, Optional, Tuple, TypeVar, Union
 
 import msgspec
 
 from pytype.pytd import pytd
 from pytype.pytd import serialize_ast
 
-
-Path = Union[str, os.PathLike[str]]
+# In Python 3.8 and below, os.PathLike isn't subscriptable.
+if sys.version_info[:2] >= (3, 9):
+  _StrPathLike = os.PathLike[str]
+else:
+  _StrPathLike = os.PathLike
+Path = Union[str, _StrPathLike]
 
 
 class LoadPickleError(Exception):
@@ -60,7 +65,8 @@ def __init__(self, filename: Path):
 
 
 def _Load(
-    dec: _Dec[_DecT], filename: Path, compress: bool = False, open_function=open
+    dec: "_Dec[_DecT]", filename: Path, compress: bool = False,
+    open_function=open,
 ) -> _DecT:
   """Loads a serialized file.
 

pytype/io.py

@@ -99,8 +99,8 @@ def check_py(src, options=None, loader=None):
 
 def generate_pyi_ast(
     src: str,
-    options: config.Options | None = None,
-    loader: load_pytd.Loader | None = None,
+    options: Optional[config.Options] = None,
+    loader: Optional[load_pytd.Loader] = None,
 ) -> analyze.Analysis:
   """Run the inferencer on a string of source code, producing output.
 

pytype/pytd/parse/node.py

@@ -12,13 +12,20 @@
 For examples of visitors, see pytd/visitors.py
 """
 
+from typing import Any, ClassVar, Type, TYPE_CHECKING
+
 import msgspec
 
 from pytype import metrics
 
+if TYPE_CHECKING:
+  _Struct: Type[Any]
+else:
+  _Struct = msgspec.Struct
+
 
 class Node(
-    msgspec.Struct,
+    _Struct,
     frozen=True,
     tag=True,
     tag_field="_struct_type",
@@ -28,7 +35,9 @@ class Node(
 ):
   """Base Node class."""
 
-  name: str = ""
+  # We pretend that `name` is a ClassVar so that msgspec treats it as a struct
+  # field only when it is defined in a subclass.
+  name: ClassVar[str] = ""
 
   def __iter__(self):
     for name in self.__struct_fields__:

pytype/pytd/pytd.py

@@ -88,7 +88,7 @@ def Get(self, name):
   def __contains__(self, name):
     return bool(self.Get(name))
 
-  def IterChildren(self) -> Generator[tuple[str, Any | None], None, None]:
+  def IterChildren(self) -> Generator[Tuple[str, Any | None], None, None]:
     for name, child in super().IterChildren():
       if name == '_name2item':
         continue
@@ -113,7 +113,7 @@ class Constant(Node):
   # (bytes is excluded because it serializes the same as str.)
   # We can't use just `value: Any` because msgspec isn't able to decode
   # AnythingType in that case, since it's indistinguishable from a dict.
-  value: Optional[Union[AnythingType, int, str, bool, tuple[str, ...]]] = None
+  value: Optional[Union[AnythingType, int, str, bool, Tuple[str, ...]]] = None
 
 
 class Alias(Node):
@@ -150,13 +150,13 @@ class Class(Node):
   """
   name: str
   keywords: Tuple[Tuple[str, TypeU], ...]
-  bases: Tuple[Union['Class', TypeU], ...]
-  methods: Tuple['Function', ...]
+  bases: Tuple[Union[Class, TypeU], ...]
+  methods: Tuple[Function, ...]
   constants: Tuple[Constant, ...]
-  classes: Tuple['Class', ...]
+  classes: Tuple[Class, ...]
   decorators: Tuple[Alias, ...]
   slots: Optional[Tuple[str, ...]]
-  template: Tuple['TemplateItem', ...]
+  template: Tuple[TemplateItem, ...]
   # _name2item is the lookup cache. It should not be treated as a child or used
   # in equality or hash operations.
   _name2item: Dict[str, Any] = {}
@@ -204,7 +204,7 @@ def __hash__(self):
     nohash = self.Replace(_name2item=None)
     return super(Class, nohash).__hash__()
 
-  def IterChildren(self) -> Generator[tuple[str, Any | None], None, None]:
+  def IterChildren(self) -> Generator[Tuple[str, Any | None], None, None]:
     for name, child in super().IterChildren():
       if name == '_name2item':
         continue
@@ -252,7 +252,7 @@ class Function(Node):
     flags: A bitfield of flags like is_abstract
   """
   name: str
-  signatures: Tuple['Signature', ...]
+  signatures: Tuple[Signature, ...]
   kind: MethodKind
   flags: MethodFlag = MethodFlag.NONE
   decorators: Tuple[Alias, ...] = ()
@@ -290,12 +290,12 @@ class Signature(Node):
     exceptions: List of exceptions for this function definition.
     template: names for bindings for bounded types in params/return_type
   """
-  params: Tuple['Parameter', ...]
-  starargs: Optional['Parameter']
-  starstarargs: Optional['Parameter']
+  params: Tuple[Parameter, ...]
+  starargs: Optional[Parameter]
+  starstarargs: Optional[Parameter]
   return_type: TypeU
   exceptions: Tuple[TypeU, ...]
-  template: Tuple['TemplateItem', ...]
+  template: Tuple[TemplateItem, ...]
 
   @property
   def has_optional(self):
@@ -462,7 +462,7 @@ class ClassType(Type, frozen=False, eq=False):
   # treated as if it doesn't exist.
   cls: Optional[Any] = None
 
-  def IterChildren(self) -> Generator[tuple[str, Any | None], None, None]:
+  def IterChildren(self) -> Generator[Tuple[str, Any | None], None, None]:
     # It is very important that visitors do not follow the cls pointer. To avoid
     # this, we claim that `name` is the only child.
     yield 'name', self.name

pytype/pytd/pytd_test.py

@@ -25,7 +25,7 @@ def test_class_type_equality(self):
 
   def test_iter(self):
     n = pytd.NamedType("int")
-    fields = [f for f in n]
+    fields = list(n)
     self.assertEqual(fields, [n.name])
 
   def test_union_type_eq(self):

requirements.txt

@@ -6,6 +6,7 @@ importlab>=0.8
 immutabledict>=4.1.0
 jinja2>=3.1.2
 libcst>=1.0.1
+msgspec>=0.18.6
 networkx<3.2
 ninja>=1.10.0.post2
 pybind11>=2.10.1

setup.cfg

@@ -36,6 +36,7 @@ install_requires =
     immutabledict>=4.1.0
     jinja2>=3.1.2
     libcst>=1.0.1
+    msgspec>=0.18.6
     networkx<3.2
     ninja>=1.10.0.post2
     pycnite>=2023.10.11