Useless addition in PyTuple_New

[decibel]

BPO	25587
Nosy	@vstinner, @serhiy-storchaka, @decibel

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2015-11-09.12:44:33.638>
created_at = <Date 2015-11-09.05:44:35.035>
labels = ['performance']
title = 'Useless addition in PyTuple_New'
updated_at = <Date 2015-11-09.12:44:33.637>
user = 'https://github.com/decibel'

bugs.python.org fields:

activity = <Date 2015-11-09.12:44:33.637>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2015-11-09.12:44:33.638>
closer = 'vstinner'
components = []
creation = <Date 2015-11-09.05:44:35.035>
creator = 'Jim Nasby'
dependencies = []
files = []
hgrepos = []
issue_num = 25587
keywords = []
message_count = 3.0
messages = ['254367', '254372', '254385']
nosy_count = 3.0
nosy_names = ['vstinner', 'serhiy.storchaka', 'Jim Nasby']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'performance'
url = 'https://bugs.python.org/issue25587'
versions = ['Python 3.6']

[decibel]

In PyTuple_New, if the new tuple won't go on the free_list:

		/* Check for overflow */
		if (nbytes / sizeof(PyObject *) != (size_t)size ||
		    (nbytes > PY_SSIZE_T_MAX - sizeof(PyTupleObject) - sizeof(PyObject *)))
		{
			return PyErr_NoMemory();
		}
		nbytes += sizeof(PyTupleObject) - sizeof(PyObject *);

nbytes is never used after the overflow check, so the last addition is a waste.

[serhiy-storchaka]

There is no such code in current sources.

[vstinner]

The line "nbytes += " was removed 5 years ago by the changeset 7be8129ee0fd. It's maybe time to update your Python version? :-)

Only Python < 2.7 has the line, it was removed before Python 2.7.0 was tagged.