inifile: add missing attributes (#10273)

And make many attributes read-only. The primary entry point to this module in `IniFile` (or its subclass
`AppIniFile`). Since the config file is read (from `filename`) and
parsed (using the `dialect`) in the `IniFile` constructor, modifying
attributes like `IniFile.filename` or `IniFile.dialect` after
construction is likely to cause problems.

stubs/inifile/@tests/stubtest_allowlist.txt

@@ -6,3 +6,18 @@ inifile.iter_from_file
 inifile.iteritems
 inifile.reraise
 inifile.string_types
+
+# Attributes that should be treated as read-only and thus are annotated
+# with @property
+inifile.Dialect.ns_sep
+inifile.Dialect.kv_sep
+inifile.Dialect.quotes
+inifile.Dialect.true
+inifile.Dialect.false
+inifile.Dialect.comments
+inifile.Dialect.allow_escaping
+inifile.Dialect.linesep
+inifile.IniData.dialect
+inifile.IniFile.filename
+inifile.IniFile.encoding
+inifile.IniFile.is_new

stubs/inifile/inifile.pyi

@@ -1,4 +1,4 @@
-from _typeshed import StrOrBytesPath, StrPath, SupportsKeysAndGetItem
+from _typeshed import StrPath, SupportsKeysAndGetItem
 from collections.abc import Container, Iterable, Iterator, Mapping, MutableMapping, Sequence
 from typing import TypeVar, overload
 from typing_extensions import Literal, TypeAlias
@@ -16,14 +16,6 @@ _Token: TypeAlias = (
 def get_app_dir(app_name: str, roaming: bool = ..., force_posix: bool = ...) -> str: ...
 
 class Dialect:
-    ns_sep: str
-    kv_sep: str
-    quotes: Sequence[str]
-    true: Sequence[str]
-    false: Sequence[str]
-    comments: Container[str]
-    allow_escaping: bool
-    linesep: str | None
     def __init__(
         self,
         ns_sep: str = ...,
@@ -35,6 +27,22 @@ class Dialect:
         allow_escaping: bool = ...,
         linesep: str | None = ...,
     ) -> None: ...
+    @property
+    def ns_sep(self) -> str: ...
+    @property
+    def kv_sep(self) -> str: ...
+    @property
+    def quotes(self) -> Sequence[str]: ...
+    @property
+    def true(self) -> Sequence[str]: ...
+    @property
+    def false(self) -> Sequence[str]: ...
+    @property
+    def comments(self) -> Container[str]: ...
+    @property
+    def allow_escaping(self) -> bool: ...
+    @property
+    def linesep(self) -> str | None: ...
     def get_actual_linesep(self) -> str: ...
     def get_strippable_lineseps(self) -> str: ...
     def kv_serialize(self, key, val: str | None) -> str | None: ...
@@ -52,6 +60,8 @@ default_dialect: Dialect
 class IniData(MutableMapping[str, str]):
     def __init__(self, mapping: Mapping[str, str] | None = ..., dialect: Dialect | None = ...) -> None: ...
     @property
+    def dialect(self) -> Dialect: ...
+    @property
     def is_dirty(self) -> bool: ...
     def get_updated_lines(self, line_iter: Iterable[_Token] | None = ...) -> list[_Token]: ...
     def discard(self) -> None: ...
@@ -99,7 +109,13 @@ class IniData(MutableMapping[str, str]):
     def __delitem__(self, name: str) -> None: ...
 
 class IniFile(IniData):
-    def __init__(self, filename: StrOrBytesPath | int, encoding: str | None = ..., dialect: Dialect | None = ...) -> None: ...
+    def __init__(self, filename: StrPath, encoding: str | None = ..., dialect: Dialect | None = ...) -> None: ...
+    @property
+    def filename(self) -> str: ...
+    @property
+    def encoding(self) -> str | None: ...
+    @property
+    def is_new(self) -> bool: ...
     def save(self, create_folder: bool = ...) -> None: ...
 
 class AppIniFile(IniFile):