Bug#845153: new ifconfig has incompatible output, please revert

Marc MERLIN marc_soft at merlins.org
Wed Nov 23 16:38:57 UTC 2016

First, thanks for your answer.

On Wed, Nov 23, 2016 at 04:25:42PM +0100, Martín Ferrari wrote:
> > Well, never mind, that new ifconfig output is almost entirely different
> > from the old one, the one that's been around for 20 years and that
> > countless people rely on being that way.
> I am sorry these changes have caused you problems. What happens is that
> nettools has been unmaintained for a very long time, that's why nothing
> has changed in all these years.

Understood. It had become a de facto API though, whether that was desired,
or not.

> Now upstream is working again, fixing many issues and adding features.
> As part of that, they have changed some of the tools' output.

Needlessly so, just enough to break just about anyone parsing ifconfig
I'm specifically unhappy because the breakage was really "just because"

> These days, I'd recommend parsing the one-line format from iproute2:
> # ip -o addr list
Just looked at it
1) it's worse output to parse
3: wlan0    inet brd scope global wlan0\ valid_lft forever preferred_lft forever

2) if ifconfig output can be changed now, who says ip output (which quite
frankly is weird looking in comparison) will not change too?

This is madness....

> But this can change too, and has changed in the past. I had already to
> fix code that broke because of those changes.


> I understand you are frustrated. But I don't want to patch this in
> Debian, nor I want to try to convince upstream to revert the output
> format, as the old one had many problems. You are free to discuss this
> issue with them, though.

I hear that you don't want to unbreak ifconfig locally in debian, I was
hoping you'd be willing to relay to them, but if not, I will.

On your side, this is sadly a gravely incompatible update that will
break an unknown amount of users as it rolls out. At the very least, you
should have some pre-install warning because once you're hit by the problem
1) your machine is likely not to reboot and come back on the net, or your
networking related stuff will break
2) people will waste valueable time tyring to figure out what broke,
potentially in a stressful environment (server down, slow serial console,
possibly on call late at night).

If debian had at had least warned me this was a potentially dangerous
upgrade, I would have stopped it an looked at it later in a proper

"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/  

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