setuptools without unexpected downloads

[Ben Finney]

Howdy all,

The Python distutils has been built upon by setuptools, providing
features asked for by many developers.

One of these is the ability for the 'setup.py' program to declare
package dependencies in a fairly standardised way, and determine if
they're met before attempting to install the package. This is good for
distributing one's software to folks whose operating system is stuck
somewhere in the mid-20th century by not providing such a dependency
system.

However, one of the areas where setuptools clashes with existing
package dependency systems is its default of *downloading* those
packages declared as dependencies, and installing them in its own way
getting in the way of the existing package dependency system.

How can I, as the distributor of a package using setuptools, gain the
benefits of dependency declaration and checking, without the drawback
of unexpected and potentially unwanted download and installation?

I know that a user can choose (if they've read the mass of setuptools
documentation) to disallow this download-and-install-dependencies
behaviour with a specific invocation of 'setup.py'. But how can I
disallow this from within the 'setup.py' program, so my users don't
have to be aware of this unexpected default behaviour?

-- 
 \       "I disapprove of what you say, but I will defend to the death |
  `\     your right to say it."  -- Evelyn Beatrice Hall, _The Friends |
_o__)                                               of Voltaire_, 1906 |
Ben Finney