[Python-Dev] Proposal: go back to enabling DeprecationWarning by default

[Toshio Kuratomi]

On Nov 7, 2017 5:47 AM, "Paul Moore" <p.f.moore at gmail.com> wrote:

On 7 November 2017 at 13:35, Philipp A. <flying-sheep at web.de> wrote:
> Sorry, I still don’t understand how any of this is a problem.
>
> If you’re an application developer, google “python disable
> DeprecationWarning” and paste the code you found, so your users don’t see
> the warnings.
> If you’re a library developer, and a library you depend on raises
> DeprecationWarnings without it being your fault, file an issue/bug there.
>
> For super-increased convenience in case 2., we could also add a
convenience
> API that blocks deprecation warnings raised from certain module or its
> submodules.
> Best, Philipp

If you're a user and your application developer didn't do (1) or a
library developer developing one of the libraries your application
developer chose to use didn't do (2), you're hosed. If you're a user
who works in an environment where moving to a new version of the
application is administratively complex, you're hosed.

As I say, the proposal prioritises developer convenience over end user
experience.


I don't agree with this characterisation.  Even if we assume a user isn't
going to fix a DeprecationWarning they still benefit: (1) if they're a
sysadmin it will warn them that they need to be careful when upgrading a
dependency. (2) if the developer never hears about the DeprecationWarning
then it is ultimately the user who suffers when the tool they depend on
breaks without warning so seeing and reporting the DeprecationWarning helps
the end user. (3) if DeprecationWarnings are allowed to linger through
multiple releases, it may tell the user about the quality of the software
they're using.

More information is helpful to end users.  Developers are actually the ones
that it inconveniences as we'll be the ones grumbling when an end user who
hasn't evaluated the deprecation cycles of upstream projects as we have
demand immediate changes for deprecations that are still years away from
causing problems.  But unlike end users, we do have the ability to solve
that by turning those deprecations off in our code if we've done our due
diligence (or even if we haven't done our due diligence).

-Toshio
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