bpo-37330: open() no longer accept 'U' in file mode (GH-16959)

open(), io.open(), codecs.open() and fileinput.FileInput no longer
accept "U" ("universal newline") in the file mode. This flag was
deprecated since Python 3.3.
This commit is contained in:
Victor Stinner 2019-10-28 15:40:08 +01:00 committed by GitHub
parent 3bfc8e0fcc
commit e471e72977
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13 changed files with 57 additions and 96 deletions

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@ -71,7 +71,6 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None,
'b' binary mode
't' text mode (default)
'+' open a disk file for updating (reading and writing)
'U' universal newline mode (deprecated)
========= ===============================================================
The default mode is 'rt' (open for reading text). For binary random
@ -87,10 +86,6 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None,
returned as strings, the bytes having been first decoded using a
platform-dependent encoding or using the specified encoding if given.
'U' mode is deprecated and will raise an exception in future versions
of Python. It has no effect in Python 3. Use newline to control
universal newlines mode.
buffering is an optional integer used to set the buffering policy.
Pass 0 to switch buffering off (only allowed in binary mode), 1 to select
line buffering (only usable in text mode), and an integer > 1 to indicate
@ -176,7 +171,7 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None,
if errors is not None and not isinstance(errors, str):
raise TypeError("invalid errors: %r" % errors)
modes = set(mode)
if modes - set("axrwb+tU") or len(mode) > len(modes):
if modes - set("axrwb+t") or len(mode) > len(modes):
raise ValueError("invalid mode: %r" % mode)
creating = "x" in modes
reading = "r" in modes
@ -185,13 +180,6 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None,
updating = "+" in modes
text = "t" in modes
binary = "b" in modes
if "U" in modes:
if creating or writing or appending or updating:
raise ValueError("mode U cannot be combined with 'x', 'w', 'a', or '+'")
import warnings
warnings.warn("'U' mode is deprecated",
DeprecationWarning, 2)
reading = True
if text and binary:
raise ValueError("can't have text and binary mode at once")
if creating + reading + writing + appending > 1: