Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!gegeweb.org!de-l.enfer-du-nord.net!feeder2.enfer-du-nord.net!newsfeed.eweka.nl!eweka.nl!feeder3.eweka.nl!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path: <rosuav@gmail.com>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.005
X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'python': 0.08; '>>>>': 0.09; 'beating': 0.09; 'valueerror:': 0.09; 'subject:error': 0.09; 'am,': 0.12; 'received:209.85.210.174': 0.13; 'received:mail- iy0-f174.google.com': 0.13; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'roy': 0.16; 'unpack': 0.16; 'worse.': 0.16; 'language': 0.17; 'wrote:': 0.18; '(most': 0.21; 'dec': 0.22; 'header:In-Reply-To:1': 0.22; 'though.': 0.23; 'string': 0.24; 'traceback': 0.24; 'language.': 0.28; 'message- id:@mail.gmail.com': 0.28; 'looks': 0.29; 'values': 0.32; 'wondering': 0.32; "isn't": 0.33; 'rather': 0.33; 'fri,': 0.34; 'to:addr:python-list': 0.34; 'too': 0.34; 'last):': 0.34; 'issue': 0.35; 'something': 0.35; 'received:google.com': 0.37; 'spent': 0.38; 'received:209.85': 0.38; 'received:209': 0.40; 'to:addr:python.org': 0.40; '2011': 0.61; 'your': 0.61; 'subject:day': 0.68; "'foo'": 0.84; 'facility,': 0.84
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=57SnyMvfvIN9MSCavBjuNCsHY2UdlGWGF1qqeHOmzNY=; b=JFNU9KM7DXibNhS9Py+5ladRKBXYD9KktMhfYP8jl7dcdE48dTaAuS3y8ZXcK3ZwPl GBKrKC0jcAQDch+TPkglYidLRxLsDihOGJO3i9jLNmKSBlEmBH7XOIHwSOe4ICjBJmu6 wVR3Tp5zCBcb1MYZLb4PJz4Z45YDwckPsHChU=
MIME-Version: 1.0
In-Reply-To: <roy-9DEDD9.09233308122011@news.panix.com>
References: <roy-9DEDD9.09233308122011@news.panix.com>
Date: Fri, 9 Dec 2011 01:40:53 +1100
Subject: Re: Misleading error message of the day
From: Chris Angelico <rosuav@gmail.com>
To: python-list@python.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.3413.1323355255.27778.python-list@python.org>
Lines: 26
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1323355255 news.xs4all.nl 6876 [2001:888:2000:d::a6]:51667
X-Complaints-To: abuse@xs4all.nl
Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:16831

On Fri, Dec 9, 2011 at 1:23 AM, Roy Smith <roy@panix.com> wrote:
> I just spent a while beating my head against this one.
>
> # Python 2.6
>>>> a, b =3D 'foo'
> Traceback (most recent call last):
> =A0File "<stdin>", line 1, in <module>
> ValueError: too many values to unpack

Definitely weird! I smell a job for a linter though. If you had just
happened to have a two-character string there, it would have quietly
succeeded, and left you wondering what was going on - imho rather
worse.

This isn't something for the language to solve; the same issue would
come up if you had something like:

a=3D[1,2,3]
b=3D[4,5,6]

c,d=3Da # oops, mucked up the "a,b" side

Or any other iterable. Looks to me like a chance for an informational
note from your lint facility, not a change to the language.

ChrisA