[Catalog-sig] pre-PEP: transition to release-file hosting at pypi site

[PJ Eby]

On Tue, Mar 12, 2013 at 2:18 PM, Carl Meyer <carl at oddbird.net> wrote:
> It seems to me that there's a remarkable level of consensus developing
> here (though it may not look like it), and a small set of remaining open
> questions.
>
> The consensus (as I see it):
>
> - Migrate away from scraping external HTML pages, with package owners in
> control of the migration but a deadline for a forced switch, as outlined
> in Holger's PEP (with all appropriate caution and testing).
>
> - In some way, migrate to a situation where the popular installer tools
> install only release files from PyPI by default, but are capable of
> installing from other locations if the user provides an option.

Perhaps I'm confused, but ISTM that every time I've said this, Donald
and Lennart argue that it should not be possible to provide such an
option -- or to be more specific, that PyPI should not publish the
information that makes that option possible.

If that's *not* the position they're taking, it'd be good to know,
because we could totally stop arguing about it in that case.


> A) Leave external links in the PyPI simple index, but migrate the major
> tools to not use external links by default (i.e. Philip's plan to make
> allow-hosts=pypi the default in a future setuptools), with an option to
> turn them back on.

I don't know who has proposed this option, but it's not me.  You seem
to be confusing external links and HTML-scraped links (rel=""
attributed links in /simple).

I was the first person to propose disabling HTML-scraped links from
PyPI *ASAP*.  I still want them gone.  That won't require tool
changes, it just requires a rollout plan.  Holger has one, let's work
on that.

The second thing I proposed is that new tools be developed to *assist*
package authors in moving their files onto PyPI, so that future tool
changes wouldn't result in widespread instances of people needing to
set their tools to insecure settings just to get anything done.  We
need to get people's files moving onto PyPI *first*, in order to make
changing the tool defaults practical.

The *only* thing I object to is the part where some people want to ban
external links from /simple, always and forever, regardless of the
package authors' choice in the matter.


> B) Do a second PyPI migration, again with a per-package toggle and
> package owners in control, to a "no external links in simple index" setting.
>
> Consider for a moment how similar the end state here is with either A or
> B. In either case, by default users install only from PyPI, but by
> providing a special option they can install from some external source.
> (In B, that special option would be something like --find-links with a
> URL). In either case, we can continue to allow packages to register
> themselves on PyPI, be found in searches, etc, without uploading release
> files to PyPI if they prefer not to; they'll just have to provide
> special installation instructions to their users in that case.

Not true: approach B means that you won't know what values to pass to
the option.

It's also confused about an important point.  All the links that
appear in /simple are *already* completely under the package author's
control.  No new switches are required to remove external links - you
can simply remove them from your releases' descriptions.  This process
could be made more transparent or easy, sure -- but it's a mistake to
say that this is granting the package owners control that they don't
already have.

What they lack control over is the rel="" attributes, short of
removing those links entirely.  That's why I've proposed having a
switch for that , as reflected in Holger's pre-PEP.


> 1) With B, we can provide a gentler migration for package owners, where
> they are in control of when the switch happens.
>
> 2) With B, all end users benefit from the new defaults, not only end
> users who update to the latest and greatest tools.
>
> 3) With B (and probably some forms of A as well), end users clearly
> state which external sources they would like to trust and install from,
> rather than having a global "trust everything!" flag, which is less
> secure and less sensible.

These 3 statements all mischaracterize things substantially, because
none of those benefits are exclusive to A, and nobody has proposed a
"trust everything" flag.  Removing rel="" attributes also benefits
everyone right away, *without* new tools.