Fixers find, rfind, etc in 'string' module

[bhy]

BPO	2899
Nosy	@birkenfeld, @benjaminp, @mitsuhiko, @yaseppochi

^{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 2010-08-22.00:18:24.557>
created_at = <Date 2008-05-17.12:30:16.037>
labels = ['type-feature', 'expert-2to3']
title = "Fixers find, rfind, etc in 'string' module"
updated_at = <Date 2010-08-22.00:18:24.535>
user = 'https://bugs.python.org/bhy'

bugs.python.org fields:

activity = <Date 2010-08-22.00:18:24.535>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = <Date 2010-08-22.00:18:24.557>
closer = 'georg.brandl'
components = ['2to3 (2.x to 3.x conversion tool)']
creation = <Date 2008-05-17.12:30:16.037>
creator = 'bhy'
dependencies = []
files = []
hgrepos = []
issue_num = 2899
keywords = []
message_count = 7.0
messages = ['66993', '77320', '77329', '77330', '81960', '81966', '114622']
nosy_count = 7.0
nosy_names = ['georg.brandl', 'collinwinter', 'benjamin.peterson', 'LambertDW', 'aronacher', 'bhy', 'sjt']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = None
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue2899'
versions = ['Python 3.0']

[bhy]

Functions like find() rfind() index() rindex() has been removed in
Python 3.0. So there should be a 2to3 fix for it.

Eg. fix
if string.find(s, "hello") >= 0:
to
if str.find(s, "hello") >= 0:

Thank you!

[lambertdw]

I expect the answer will be that 2to3 cannot know what sort of object
"string" names. Bell's theorem, or some such, as I understand it, tells
us that you must execute the algorithm to find out what it does, there
isn't a short cut.

It does seem like 2to3 could assume that you write code with honorable
intention, grace, and style and thereby offer a suggestive note. The
string module is not an isolated case for such notices. I made a
similar request to yours for "file" which is gone in version 3.

Unfortunately, code as follows is probably frequent, so we aren't likely
to get support for this feature. Maybe here is an opportunity for
venture capital!

def f(list):
    '''
        argument should be a list.
        "list" in this scope no longer names __builtins__.list
    '''

[mitsuhiko]

2to3 could handle it, but it would be a lot of work for something
unnecessary. You can use "s.replace(a, b)" instead of string.replace(s,
a, b) since at least 2.0.

[lambertdw]

I think the point is to get a message from 2to3 about possible use of
feature that is gone. Of course python3 raises an exception when trying
to execute the code, but it does leave the user wondering "why did 2to3
report that there are no changes necessary?".

[yaseppochi]

Maybe 2to3 could get a --pedantic or even an --annoying option? I agree
that it should be noisy about removed features even if actually fixing
this kind of thing would be hard to do reliably.

[benjaminp]

I disagree. That is the role of -3 warnings. Static analysis is too
limited to get into issuing warnings with.

[birkenfeld]

I guess this will not happen then.