[Python-Dev] bytearray methods returning self...

Dino Viehland dinov at microsoft.com
Tue Nov 18 22:30:12 CET 2008

Sure, it's now bug 4348 - http://bugs.python.org/issue4348

-----Original Message-----
From: gvanrossum at gmail.com [mailto:gvanrossum at gmail.com] On Behalf Of Guido van Rossum
Sent: Tuesday, November 18, 2008 1:14 PM
To: Dino Viehland
Cc: python-dev at python.org dev
Subject: Re: [Python-Dev] bytearray methods returning self...

Good catch, this is a bug IMO and we should fix it in 2.6.1 and 3.0rc3.

Mind filing a bug so we can keep track of it?


On Tue, Nov 18, 2008 at 1:01 PM, Dino Viehland <dinov at microsoft.com> wrote:
> I've been implementing bytearray for IronPython and I noticed a couple of spots where the non-mutating methods of bytearray return self.
> In 2.6 but not in 3.0 RC2:
> x = bytearray(b'abc')
> y = x.replace(b'abc', b'bar', 0)
> id(x) == id(y)
> In 2.6 and in 3.0 RC2:
> t = bytearray()
> for i in range(256): t.append(i)
> x = bytearray(b'')
> y = x.translate(t)
> id(x) == id(y)
> Given that bytearray always returns a new instance on all of the other methods shouldn't it return a new instance here as well?  I'm just thinking someone could be planning on mutating the result here and not expecting their original bytearray to be mutated.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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