Author tanzer@swing.co.at
Recipients r.david.murray, tanzer@swing.co.at
Date 2015-11-05.09:58:19
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In-reply-to Your message of "Wed, 04 Nov 2015 18:29:00 +0000" <1446661740.5.0.2692128738.issue25545@psf.upfronthosting.co.za>
Content
> Yes, the port from python2 to python3 of the email package
> was...suboptimal.
> ...
> The whole concept of using unicode as a 7bit data channel only is
> just...weird.

+100 to both.

> But, we are now stuck with maintaining that API for backward
> compatibility reasons.

That's a weird definition of backward compatibility, though. The API
breaks backward compatibility to Python 2. Any Python 3 user shouldn't
use the broken API anyway, IMHO.

> To fix it, I rewrote significant parts of the email package, which
> is the new API.

Which unfortunately isn't any help if one needs to stay compatible to
2.7.

> It also is...fraught with the danger of bugs...to talk about
> serializing an email message as a string, transforming it, and then
> trying to re-parse it as an email message.  If your transformations
> are simple, it will probably work, but anything at all complex runs
> the risk of breaking the message.

One of Python's mottos used to be:

   We are all consenting adults here.

But there are other uses for converting a message instance to a
unicode string. Display, printing, and grepping come to mind.

> And having non-ascii bodies counts as non-trivial.

For anybody living in a non-ascii country that statement sounds
**very strange**.

To start with, I have many friends with names that contain non-ascii
characters.

> You do have to conditionalize your 2/3 code to use the bytes parser
> and generator if you are dealing with 8-bit messages. There's just no
> way around that.

I did that yesterday. There are problems with that though:

* Recognizing the problem for what it is.

  Trying to run Python 2.7 code that *should* run under 3.5 but breaks
  with weird errors wastes a lot of time.

  Multiply with the number of Python programmers that want to migrate
  and you get a problem.

  If `message_as_string` and `as_string` just weren't there in 3.x it
  would be much less of a problem (clear documentation would also help
  but not as much).

* Lots of ugly workarounds for the same problem.

  Most of them (mine certainly included) are done quick and ad-hoc and
  probably break in many ways.

  The question then arises: why should one use the email package at
  all. But of course that way lies madness.

Just more roadblocks for the move to Python 3.
History
Date User Action Args
2015-11-05 09:58:20tanzer@swing.co.atsetrecipients: + tanzer@swing.co.at, r.david.murray
2015-11-05 09:58:19tanzer@swing.co.atlinkissue25545 messages
2015-11-05 09:58:19tanzer@swing.co.atcreate