From cf57c85c096124e876945ad2f77f0bdedac0249a Mon Sep 17 00:00:00 2001
From: Marco Gorelli <marcogorelli@protonmail.com>
Date: Wed, 26 May 2021 21:04:05 +0100
Subject: [PATCH] deprecate positional args in read_csv

---
 doc/source/whatsnew/v1.3.0.rst                     |  2 ++
 pandas/io/parsers/readers.py                       |  8 +++++++-
 pandas/tests/io/parser/common/test_common_basic.py | 12 ++++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v1.3.0.rst b/doc/source/whatsnew/v1.3.0.rst
index fe88cf93886ce..963164528bba2 100644
--- a/doc/source/whatsnew/v1.3.0.rst
+++ b/doc/source/whatsnew/v1.3.0.rst
@@ -691,6 +691,8 @@ Deprecations
 - Deprecated passing arguments as positional in :meth:`DataFrame.reset_index` (other than ``"level"``) and :meth:`Series.reset_index` (:issue:`41485`)
 - Deprecated construction of :class:`Series` or :class:`DataFrame` with ``DatetimeTZDtype`` data and ``datetime64[ns]`` dtype.  Use ``Series(data).dt.tz_localize(None)`` instead (:issue:`41555`,:issue:`33401`)
 - Deprecated passing arguments as positional in :meth:`DataFrame.where` and :meth:`Series.where` (other than ``"cond"`` and ``"other"``) (:issue:`41485`)
+- Deprecated passing arguments as positional (other than ``filepath_or_buffer``) in :func:`read_csv` (:issue:`41485`)
+-
 
 .. _whatsnew_130.deprecations.nuisance_columns:
 
diff --git a/pandas/io/parsers/readers.py b/pandas/io/parsers/readers.py
index ad08b8d4b7097..d957a669351c1 100644
--- a/pandas/io/parsers/readers.py
+++ b/pandas/io/parsers/readers.py
@@ -30,7 +30,10 @@
     AbstractMethodError,
     ParserWarning,
 )
-from pandas.util._decorators import Appender
+from pandas.util._decorators import (
+    Appender,
+    deprecate_nonkeyword_arguments,
+)
 
 from pandas.core.dtypes.common import (
     is_file_like,
@@ -472,6 +475,9 @@ def _read(filepath_or_buffer: FilePathOrBuffer, kwds):
         return parser.read(nrows)
 
 
+@deprecate_nonkeyword_arguments(
+    version=None, allowed_args=["filepath_or_buffer"], stacklevel=3
+)
 @Appender(
     _doc_read_csv_and_table.format(
         func_name="read_csv",
diff --git a/pandas/tests/io/parser/common/test_common_basic.py b/pandas/tests/io/parser/common/test_common_basic.py
index adafbf38439d5..eba5e52516b4c 100644
--- a/pandas/tests/io/parser/common/test_common_basic.py
+++ b/pandas/tests/io/parser/common/test_common_basic.py
@@ -733,6 +733,18 @@ def test_read_csv_delimiter_and_sep_no_default(all_parsers):
         parser.read_csv(f, sep=" ", delimiter=".")
 
 
+def test_read_csv_posargs_deprecation(all_parsers):
+    # GH 41485
+    f = StringIO("a,b\n1,2")
+    parser = all_parsers
+    msg = (
+        "In a future version of pandas all arguments of read_csv "
+        "except for the argument 'filepath_or_buffer' will be keyword-only"
+    )
+    with tm.assert_produces_warning(FutureWarning, match=msg):
+        parser.read_csv(f, " ")
+
+
 @pytest.mark.parametrize("delimiter", [",", "\t"])
 def test_read_table_delim_whitespace_non_default_sep(all_parsers, delimiter):
     # GH: 35958