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Date: Wed, 18 Mar 2015 08:53:02 +1100
From: Cameron Simpson <cs@zip.com.au>
To: python-list@python.org
Subject: Re: Python 2 to 3 conversion - embrace the pain
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On 17Mar2015 05:30, Mario Figueiredo <marfig@gmail.com> wrote:
>On Tue, 17 Mar 2015 14:42:42 +1100, Ben Finney
><ben+python@benfinney.id.au> wrote:
>>Mario Figueiredo <marfig@gmail.com> writes:
>>> On Tue, 17 Mar 2015 09:02:38 +1100, Chris Angelico <rosuav@gmail.com>
>>> wrote:
>>> >Imagine you need a PostgreSQL database for your Python application -
>>> >which also means you need psycopg2, of course. How do you go about
>>> >writing installation instructions?
>>> >
>>> >* WINDOWS *
>>> >1) Install the latest Python 3 from https://www.python.org/downloads/w=
indows/
>>> >2) Install the appropriate version of psycopg2 from
>>> >http://www.stickpeople.com/projects/python/win-psycopg/
>>> >3) Install the latest PostgreSQL from
>>> >http://www.postgresql.org/download/windows/
>>> >4) Install my program from blah blah blah
>>> >
>>>
>>> Are you saying this is a problem for any developer?
>>
>>Yes. They need to write installation instructions, and the more complex
>>those instructions are the fewer prospective users will bother.
>
>The prospective users in this context are software developers. If
>software developers can't understand instructions and can't be
>bothered following linear procedures, they cannot write good code.

"Linear procedures" often only look that way because the list is shortened,=
=20
yea, even unto just headings.

There can be multiple ways to do each step, especially if one is juggling (=
or=20
considering juggling) multiple versions. If one has to iterate then each of=
=20
these steps can have internal loops and the whole process can require=20
backtracking to redo things. Possible issues include around buggy releases =
of=20
components, unfortunate decisions about the install regime, issues with the=
=20
local dev environment (eg compile steps requiring unmentioned or special=20
packages in the platform which may not be installed from the supplier), bui=
ld=20
options on/off, build tools requiring special (and ideally, badly or un-=20
documented) config options (I am looking at you, RHEL lib64 stuff with=20
autoconf).

I distribute an adzapping tool. It has two install modes, the default simpl=
e=20
one and the optional more configurable one. The simple one reads:

  - make sure you have squid installed
  - install the script (a single perl script) somewhere on your system
  - add a single line to your squid config

One recurring request from some users is separation of the zapping patterns=
=20
=66rom the script; as shipped it is a single file with the patterns embedde=
d. I=20
have resisted this _because_ it would make installs _much_ harder for users.

Alternative anecdote: long ago when escaping from CVS to a newer VCS, I loo=
ked=20
at SVN.  It was popular, etc. But the install/build chain was insane. Many=
=20
prerequisite libraries, none available from the OS supplier, all needing=20
special build/installs, and there were certainly buggy prerequisite library=
=20
releases to be tripped over and avoided. A nightmare.

Not worth the bother. And I bothered for a long time trying to get it=20
installed.

Compare Mercurial. Really easy, worked immediately, etc. Guess which I use.

IMO Mercurial is better anyway, but SVN shot itself in the foot with the=20
install requirements.

I'm capable of following linear procedures. But I'm also capable of decidin=
g=20
that procedures are unreasonably complex, especially when they have bugs.

Cheers,
Cameron Simpson <cs@zip.com.au>

Wagner's music is better than it sounds.        - Mark Twain