TYP: type read_xml and deprecate passing positional arguments

doc/source/whatsnew/v1.4.0.rst

@@ -602,6 +602,7 @@ Other Deprecations
 - Deprecated the ``prefix`` keyword argument in :func:`read_csv` and :func:`read_table`, in a future version the argument will be removed (:issue:`43396`)
 - Deprecated passing non boolean argument to sort in :func:`concat` (:issue:`41518`)
 - Deprecated passing arguments as positional for :func:`read_fwf` other than ``filepath_or_buffer`` (:issue:`41485`):
+- Deprecated passing arguments as positional for :func:`read_xml` other than ``path_or_buffer`` (:issue:`45133`):
 - Deprecated passing ``skipna=None`` for :meth:`DataFrame.mad` and :meth:`Series.mad`, pass ``skipna=True`` instead (:issue:`44580`)
 - Deprecated :meth:`DateOffset.apply`, use ``offset + other`` instead (:issue:`44522`)
 - Deprecated parameter ``names`` in :meth:`Index.copy` (:issue:`44916`)

pandas/_typing.py

@@ -246,6 +246,7 @@ def closed(self) -> bool:
 CompressionOptions = Optional[
     Union[Literal["infer", "gzip", "bz2", "zip", "xz", "zstd"], CompressionDict]
 ]
+XMLParsers = Literal["lxml", "etree"]
 
 
 # types in DataFrameFormatter

pandas/io/xml.py

@@ -5,19 +5,24 @@
 from __future__ import annotations
 
 import io
+from typing import Sequence
 
 from pandas._typing import (
     CompressionOptions,
     FilePath,
     ReadBuffer,
     StorageOptions,
+    XMLParsers,
 )
 from pandas.compat._optional import import_optional_dependency
 from pandas.errors import (
     AbstractMethodError,
     ParserError,
 )
-from pandas.util._decorators import doc
+from pandas.util._decorators import (
+    deprecate_nonkeyword_arguments,
+    doc,
+)
 
 from pandas.core.dtypes.common import is_list_like
 
@@ -98,17 +103,17 @@ class _XMLFrameParser:
 
     def __init__(
         self,
-        path_or_buffer,
-        xpath,
-        namespaces,
-        elems_only,
-        attrs_only,
-        names,
-        encoding,
-        stylesheet,
+        path_or_buffer: FilePath | ReadBuffer[bytes] | ReadBuffer[str],
+        xpath: str,
+        namespaces: dict | None,
+        elems_only: bool,
+        attrs_only: bool,
+        names: Sequence[str] | None,
+        encoding: str | None,
+        stylesheet: FilePath | ReadBuffer[bytes] | ReadBuffer[str] | None,
         compression: CompressionOptions,
         storage_options: StorageOptions,
-    ) -> None:
+    ):
         self.path_or_buffer = path_or_buffer
         self.xpath = xpath
         self.namespaces = namespaces
@@ -371,9 +376,6 @@ class _LxmlFrameParser(_XMLFrameParser):
     XPath 1.0 and XSLT 1.0.
     """
 
-    def __init__(self, *args, **kwargs) -> None:
-        super().__init__(*args, **kwargs)
-
     def parse_data(self) -> list[dict[str, str | None]]:
         """
         Parse xml data.
@@ -544,6 +546,11 @@ def _parse_doc(self, raw_doc) -> bytes:
             curr_parser = XMLParser(encoding=self.encoding)
 
             if isinstance(xml_data, io.StringIO):
+                if self.encoding is None:
+                    raise TypeError(
+                        "Can not pass encoding None when input is StringIO."
+                    )
+
                 doc = fromstring(
                     xml_data.getvalue().encode(self.encoding), parser=curr_parser
                 )
@@ -570,7 +577,7 @@ def _transform_doc(self) -> bytes:
 
 def get_data_from_filepath(
     filepath_or_buffer: FilePath | bytes | ReadBuffer[bytes] | ReadBuffer[str],
-    encoding,
+    encoding: str | None,
     compression: CompressionOptions,
     storage_options: StorageOptions,
 ) -> str | bytes | ReadBuffer[bytes] | ReadBuffer[str]:
@@ -658,15 +665,15 @@ class that build Data Frame and infers specific dtypes.
 
 
 def _parse(
-    path_or_buffer,
-    xpath,
-    namespaces,
-    elems_only,
-    attrs_only,
-    names,
-    encoding,
-    parser,
-    stylesheet,
+    path_or_buffer: FilePath | ReadBuffer[bytes] | ReadBuffer[str],
+    xpath: str,
+    namespaces: dict | None,
+    elems_only: bool,
+    attrs_only: bool,
+    names: Sequence[str] | None,
+    encoding: str | None,
+    parser: XMLParsers,
+    stylesheet: FilePath | ReadBuffer[bytes] | ReadBuffer[str] | None,
     compression: CompressionOptions,
     storage_options: StorageOptions,
     **kwargs,
@@ -686,11 +693,11 @@ def _parse(
         * If parser is not lxml or etree.
     """
 
-    lxml = import_optional_dependency("lxml.etree", errors="ignore")
-
     p: _EtreeFrameParser | _LxmlFrameParser
 
     if parser == "lxml":
+        lxml = import_optional_dependency("lxml.etree", errors="ignore")
+
         if lxml is not None:
             p = _LxmlFrameParser(
                 path_or_buffer,
@@ -728,19 +735,23 @@ def _parse(
     return _data_to_frame(data=data_dicts, **kwargs)
 
 
+@deprecate_nonkeyword_arguments(
+    version=None, allowed_args=["path_or_buffer"], stacklevel=2
+)
 @doc(
     storage_options=_shared_docs["storage_options"],
     decompression_options=_shared_docs["decompression_options"] % "path_or_buffer",
 )
 def read_xml(
     path_or_buffer: FilePath | ReadBuffer[bytes] | ReadBuffer[str],
-    xpath: str | None = "./*",
-    namespaces: dict | list[dict] | None = None,
-    elems_only: bool | None = False,
-    attrs_only: bool | None = False,
-    names: list[str] | None = None,
+    xpath: str = "./*",
+    namespaces: dict | None = None,
+    elems_only: bool = False,
+    attrs_only: bool = False,
+    names: Sequence[str] | None = None,
+    # encoding can not be None for lxml and StringIO input
     encoding: str | None = "utf-8",
-    parser: str | None = "lxml",
+    parser: XMLParsers = "lxml",
     stylesheet: FilePath | ReadBuffer[bytes] | ReadBuffer[str] | None = None,
     compression: CompressionOptions = "infer",
     storage_options: StorageOptions = None,
@@ -765,7 +776,7 @@ def read_xml(
         expressions. For more complex XPath, use ``lxml`` which requires
         installation.
 
-    namespaces : dict, optional
+    namespaces : dict, list of dicts, optional
         The namespaces defined in XML document as dicts with key being
         namespace prefix and value the URI. There is no need to include all
         namespaces in XML, only the ones used in ``xpath`` expression.

pandas/tests/io/xml/test_xml.py

@@ -769,6 +769,18 @@ def test_stylesheet_file(datapath):
     tm.assert_frame_equal(df_kml, df_style)
 
 
+def test_read_xml_passing_as_positional_deprecated(datapath):
+    # GH#45133
+    kml = datapath("io", "data", "xml", "cta_rail_lines.kml")
+
+    with tm.assert_produces_warning(FutureWarning, match="keyword-only"):
+        read_xml(
+            kml,
+            ".//k:Placemark",
+            namespaces={"k": "http://www.opengis.net/kml/2.2"},
+        )
+
+
 @td.skip_if_no("lxml")
 def test_stylesheet_file_like(datapath, mode):
     kml = datapath("io", "data", "xml", "cta_rail_lines.kml")