Typeshed cherry-pick: stdlib/xml: fix return types for toxml/topretty…

…xml methods (#10061)

mypy/typeshed/stdlib/xml/dom/minidom.pyi

@@ -1,7 +1,7 @@
 import sys
 import xml.dom
 from _typeshed import Incomplete, ReadableBuffer, SupportsRead, SupportsWrite
-from typing import NoReturn, TypeVar
+from typing import NoReturn, TypeVar, overload
 from typing_extensions import Literal, Self
 from xml.dom.minicompat import NodeList
 from xml.dom.xmlbuilder import DocumentLS, DOMImplementationLS
@@ -30,13 +30,69 @@ class Node(xml.dom.Node):
  def localName(self) -> str | None: ...
  def __bool__(self) -> Literal[True]: ...
  if sys.version_info >= (3, 9):
- def toxml(self, encoding: str | None = None, standalone: bool | None = None) -> str: ...
+ @overload
+ def toxml(self, encoding: str, standalone: bool | None = None) -> bytes: ...
+ @overload
+ def toxml(self, encoding: None = None, standalone: bool | None = None) -> str: ...
+ @overload
  def toprettyxml(
- self, indent: str = "\t", newl: str = "\n", encoding: str | None = None, standalone: bool | None = None
+ self,
+ indent: str = "\t",
+ newl: str = "\n",
+ # Handle any case where encoding is not provided or where it is passed with None
+ encoding: None = None,
+ standalone: bool | None = None,
  ) -> str: ...
+ @overload
+ def toprettyxml(
+ self,
+ indent: str,
+ newl: str,
+ # Handle cases where encoding is passed as str *positionally*
+ encoding: str,
+ standalone: bool | None = None,
+ ) -> bytes: ...
+ @overload
+ def toprettyxml(
+ self,
+ indent: str = "\t",
+ newl: str = "\n",
+ # Handle all cases where encoding is passed as a keyword argument; because standalone
+ # comes after, it will also have to be a keyword arg if encoding is
+ *,
+ encoding: str,
+ standalone: bool | None = None,
+ ) -> bytes: ...
  else:
- def toxml(self, encoding: str | None = None): ...
- def toprettyxml(self, indent: str = "\t", newl: str = "\n", encoding: str | None = None): ...
+ @overload
+ def toxml(self, encoding: str) -> bytes: ...
+ @overload
+ def toxml(self, encoding: None = None) -> str: ...
+ @overload
+ def toprettyxml(
+ self,
+ indent: str = "\t",
+ newl: str = "\n",
+ # Handle any case where encoding is not provided or where it is passed with None
+ encoding: None = None,
+ ) -> str: ...
+ @overload
+ def toprettyxml(
+ self,
+ indent: str,
+ newl: str,
+ # Handle cases where encoding is passed as str *positionally*
+ encoding: str,
+ ) -> bytes: ...
+ @overload
+ def toprettyxml(
+ self,
+ indent: str = "\t",
+ newl: str = "\n",
+ # Handle all cases where encoding is passed as a keyword argument
+ *,
+ encoding: str,
+ ) -> bytes: ...
 
  def hasChildNodes(self) -> bool: ...
  def insertBefore(self, newChild, refChild): ...

mypy/typeshed/test_cases/stdlib/check_xml.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+import sys
+from typing_extensions import assert_type
+from xml.dom.minidom import Document
+
+document = Document()
+
+assert_type(document.toxml(), str)
+assert_type(document.toxml(encoding=None), str)
+assert_type(document.toxml(encoding="UTF8"), bytes)
+assert_type(document.toxml("UTF8"), bytes)
+if sys.version_info >= (3, 9):
+ assert_type(document.toxml(standalone=True), str)
+ assert_type(document.toxml("UTF8", True), bytes)
+ assert_type(document.toxml(encoding="UTF8", standalone=True), bytes)
+
+
+# Because toprettyxml can mix positional and keyword variants of the "encoding" argument, which
+# determines the return type, the proper stub typing isn't immediately obvious. This is a basic
+# brute-force sanity check.
+# Test cases like toxml
+assert_type(document.toprettyxml(), str)
+assert_type(document.toprettyxml(encoding=None), str)
+assert_type(document.toprettyxml(encoding="UTF8"), bytes)
+if sys.version_info >= (3, 9):
+ assert_type(document.toprettyxml(standalone=True), str)
+ assert_type(document.toprettyxml(encoding="UTF8", standalone=True), bytes)
+# Test cases unique to toprettyxml
+assert_type(document.toprettyxml(" "), str)
+assert_type(document.toprettyxml(" ", "\r\n"), str)
+assert_type(document.toprettyxml(" ", "\r\n", "UTF8"), bytes)
+if sys.version_info >= (3, 9):
+ assert_type(document.toprettyxml(" ", "\r\n", "UTF8", True), bytes)
+ assert_type(document.toprettyxml(" ", "\r\n", standalone=True), str)