Re: cascading python executions only if return code is 0

Date	2013-12-23 04:45 -0800
From	Ethan Furman <ethan@stoneleaf.us>
Subject	Re: cascading python executions only if return code is 0
References	<mailman.4500.1387739297.18130.python-list@python.org> <52b782db$0$6599$c3e8da3$5496439d@news.astraweb.com> <roy-5F73A5.20241022122013@news.panix.com> <52b7a0e4$0$29994$c3e8da3$5496439d@news.astraweb.com> <roy-3D1D2D.23572922122013@news.panix.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.4553.1387804133.18130.python-list@python.org> (permalink)

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On 12/22/2013 08:57 PM, Roy Smith wrote:
> In article <52b7a0e4$0$29994$c3e8da3$5496439d@news.astraweb.com>,
>   Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:
>
>> Anyway, I may be completely misinterpreting what I'm reading. Perhaps the
>> assertion is checking a function invariant ("one of the strategies will
>> always succeed") in which case you're doing it exactly right and I should
>> shut up now :-)
>
> Yes :-)
>
> More specifically, the assertion exception will get caught way up in
> some django middleware which will log a stack trace and return a HTTP
> 50-something.  This will typically be followed by somebody like me
> noticing the stack dump and trying to figure out WTF happened.

This is completely misusing what assertions are for.  I hope this bit of middleware (or django itself) is very clear 
about never running with assertions turned off.


> Assertions are great tools.

Only when used properly.

>People should use them more often.

I see them being (mis)used too much as it is.

>In a
> sense, they're executable comments.  They're a programmer's way of
> standing on a hilltop and shouting to all the world, "I swear to you,
> this is true.  There may be a gazillion lines of code out there and
> GBytes of program state, but right here, right now, within this circle
> I've drawn in the sand,

Considering how easy it is to disable assertions, a circle in the sand is an amazingly appropriate metaphor.  :)

--
~Ethan~

Thread

cascading python executions only if return code is 0 Frank Cui <ycui@outlook.com> - 2013-12-22 15:37 -0300
  Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-22 14:17 -0500
    Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-22 19:31 +0000
      Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-22 15:05 -0500
        Re: cascading python executions only if return code is 0 Cameron Simpson <cs@zip.com.au> - 2013-12-23 08:39 +1100
          Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-22 16:53 -0500
            Re: cascading python executions only if return code is 0 Cameron Simpson <cs@zip.com.au> - 2013-12-23 09:11 +1100
            Re: cascading python executions only if return code is 0 Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-22 22:10 -0500
            Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 14:22 +1100
            Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-23 03:43 +0000
            Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 14:45 +1100
            Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-23 03:54 +0000
            Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 14:59 +1100
    RE: cascading python executions only if return code is 0 Frank Cui <ycui@outlook.com> - 2013-12-22 16:10 -0300
    Re: cascading python executions only if return code is 0 Ned Batchelder <ned@nedbatchelder.com> - 2013-12-22 14:49 -0500
      Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-23 00:08 +0000
    RE: cascading python executions only if return code is 0 Frank Cui <ycui@outlook.com> - 2013-12-22 16:35 -0300
      Re: cascading python executions only if return code is 0 Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-23 13:30 +1300
  Re: cascading python executions only if return code is 0 Rick Johnson <rantingrickjohnson@gmail.com> - 2013-12-22 14:27 -0800
    RE: cascading python executions only if return code is 0 Frank Cui <ycui@outlook.com> - 2013-12-22 19:14 -0300
    Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 09:51 +1100
    Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-22 23:02 +0000
      Re: cascading python executions only if return code is 0 Rick Johnson <rantingrickjohnson@gmail.com> - 2013-12-22 15:57 -0800
        Re: cascading python executions only if return code is 0 Ned Batchelder <ned@nedbatchelder.com> - 2013-12-23 07:27 -0500
        Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-23 12:44 +0000
  Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-23 00:25 +0000
    Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-22 20:24 -0500
      Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 12:35 +1100
      Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-23 13:33 +1100
        Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 14:09 +1100
        Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-22 23:57 -0500
          Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-23 16:09 +1100
          Re: cascading python executions only if return code is 0 Ethan Furman <ethan@stoneleaf.us> - 2013-12-23 04:45 -0800
            Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-23 10:10 -0500
              Re: cascading python executions only if return code is 0 Ethan Furman <ethan@stoneleaf.us> - 2013-12-23 08:00 -0800
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-26 20:37 -0500
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-27 12:44 +1100
                Re: cascading python executions only if return code is 0 Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-26 21:20 -0500
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-27 13:27 +1100
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-26 23:29 -0500
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-27 15:40 +1100
                Re: cascading python executions only if return code is 0 Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-27 11:15 -0500
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-27 11:42 -0500
                Re: cascading python executions only if return code is 0 Rustom Mody <rustompmody@gmail.com> - 2013-12-27 22:39 +0530
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-28 08:24 +1100
                Re: cascading python executions only if return code is 0 pecore@pascolo.net - 2013-12-28 00:59 +0100
                Re: cascading python executions only if return code is 0 Gene Heskett <gheskett@wdtv.com> - 2013-12-27 19:12 -0500
                Re: cascading python executions only if return code is 0 Tim Chase <python.list@tim.thechases.com> - 2013-12-26 20:50 -0600
                Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-27 15:39 +1100
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-27 15:45 +1100
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-27 00:05 -0500
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-27 16:15 +1100
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-27 00:41 -0500
                Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-27 18:00 +0000
                Re: cascading python executions only if return code is 0 Grant Edwards <invalid@invalid.invalid> - 2013-12-30 17:36 +0000
              Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-24 04:05 +1100
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-23 11:03 -0800
                Re: cascading python executions only if return code is 0 Chris Angelico <rosuav@gmail.com> - 2013-12-24 06:12 +1100
                RE: cascading python executions only if return code is 0 Nick Cash <nick.cash@npcinternational.com> - 2013-12-23 19:31 +0000
                Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-24 14:41 +1100
                Re: cascading python executions only if return code is 0 Roy Smith <roy@panix.com> - 2013-12-23 22:58 -0500
              Re: cascading python executions only if return code is 0 Peter Otten <__peter__@web.de> - 2013-12-23 18:45 +0100
          Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-23 13:20 +0000
        Re: cascading python executions only if return code is 0 Ethan Furman <ethan@stoneleaf.us> - 2013-12-23 04:38 -0800
        Re: cascading python executions only if return code is 0 Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-23 10:12 -0500
          Re: cascading python executions only if return code is 0 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-24 04:13 +1100
        Re: cascading python executions only if return code is 0 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-23 15:22 +0000

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