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Re: Two stages of debugging

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On Tuesday, 18 September 2018 16:19:23 UTC+2, Wouter Verhelst  wrote:
> On 9/18/18 1:43 PM, Julio Di Egidio wrote:
> > On Tuesday, 18 September 2018 13:08:25 UTC+2, Wouter Verhelst  wrote:
> >> On 9/18/18 12:46 PM, Julio Di Egidio wrote:
<snipped>

> > Yet I'd argue that, even at that level, 100% coverage, now of the
> > requirements, is a rather counter-productive myth.
> 
> I agree that it's difficult to reach .

It's *impossible* *in principle*, and, as for all these myths, aiming for
it cannot but be a recipe for disaster under all respects: from the useless
extra effort, to expectations never fulfilled, finally to, which is the real
underlying fraud (talking about the whole arena now), the misunderstanding and
misrepresentation of the very state of the art.

> >> less bugs, not more, and that way you will eventually converge on a
> >> version of the program which is almost perfectly correct.
> > 
> > That's another myth: the solution landscape is (nearly?) chaotic, so all you
> > converge to with a local approach is a local minimum, and a very suboptimal
> > one with probability (nearly?) one.  Indeed, that's one of the two or three
> > reasons why TDD in particular is like shooting in one's own foot, twice...
> 
> The above statement assumed that the software is feature-complete. If it
> isn't, then yes, at some point you need to write new functionality, and
> that new functionality might be buggy (at least the first version of it
> could be), so you introduce new bugs.
> 
> However, if your test suite is sufficiently complete, adding that new
> functionality shouldn't introduce major new bugs in the already existing
> code.

Nope, even assuming that by some unspoken magic you get to the point of having
correct enough code and tests, adding any new features or changing existing
ones is still *not* a "local" change and does *not* guarantee any "continuity".
You change a random character in a million lines code and it won't even compile
in the general case, let alone remain correct.  --  And TDD is worse than
nonsense not just under that respect, more could be said, about the mythical
direct mapping of requirements (the problem domain) to specifications (the
solution domain)...

> However, it
> is important to set your expectations right; as with many things, there
> is no silver bullet

Which really is the self-apologetics of those myths: the denial of an actual
discipline and of an actual knowledge of what there is to know.  That stuff
is not simply not a silver bullet, that stuff is badly broken and badly
damaging, the entire category and the entire market...

Anyway, I might give more details if anybody asks, but I won't insist.

HTH,

Julio

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Two stages of debugging Victor Porton <porton@narod.ru> - 2018-09-17 23:31 +0300
  Re: Two stages of debugging David Brown <david.brown@hesbynett.no> - 2018-09-18 09:13 +0200
    Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-18 03:39 -0700
  Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-18 03:34 -0700
  Re: Two stages of debugging Wouter Verhelst <w@uter.be> - 2018-09-18 12:40 +0200
    Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-18 03:46 -0700
      Re: Two stages of debugging Wouter Verhelst <w@uter.be> - 2018-09-18 13:08 +0200
        Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-18 04:43 -0700
          Re: Two stages of debugging Wouter Verhelst <w@uter.be> - 2018-09-18 16:00 +0200
            Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-18 10:36 -0700
              Re: Two stages of debugging Jacob Sparre Andersen <jacob@jacob-sparre.dk> - 2018-09-19 07:51 +0200
                Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-19 03:43 -0700
              On the usefulness of testing coverage (was: Re: Two stages of debugging) Wouter Verhelst <w@uter.be> - 2018-09-19 13:46 +0200
                Re: On the usefulness of testing coverage (was: Re: Two stages of debugging) Julio Di Egidio <julio@diegidio.name> - 2018-09-19 08:20 -0700
            Re: Two stages of debugging Ed Prochak <edprochak@gmail.com> - 2018-09-18 12:02 -0700
              Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-19 03:39 -0700
  Re: Two stages of debugging Victor Porton <porton@narod.ru> - 2018-09-20 22:37 +0300
    Re: Two stages of debugging Julio Di Egidio <julio@diegidio.name> - 2018-09-20 12:53 -0700

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