Iso8601 format

[ericmoritz]

This makes ISO8601 the default for DateTimeField, DateField and TimeField.

This is backwards compatible with version 0.5.0 because format was an required argument for date based fields.

[JNRowe]

Would you consider making this default to importing the system version of pyso8601 if it is available? I realise bundling packages makes life easier in some setups, but I know I'm going to hit a massive brick wall if I ask our admins to roll out micromodels updates that include bundled libraries.

[ericmoritz]

I can. I am just curious to why there would be an objection if the bundled package is namespaced at micromodels.packages. This is what the requests package does.

[JNRowe]

I am just curious to why there would be an objection if the bundled package is namespaced at micromodels.packages.

It means taking on the maintenance burden for a chunk of code twice(or more if it happened elsewhere too).

The funny thing is I looked at it entirely the other way, I can't understand why it would be bundled in the first place. Of course, that is your call but I just wanted to ask.

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The longer version...

Fedora helpfully have a really nice document about this and the Debian folks have a short policy note explaining the reasons to avoid bundling.

This is what the requests package does.

Oddly, you seem to have picked an example that I would probably have used as a counter argument ;)

The requests package gets special treatment in debian for its urllib3 bundling, see the changelog or the packaging tarball for details.

Debian also pull the six bundling out. Having just looked at the repo a new heap of libraries have been recently bundled, which one would expect means more patches to pile up soon.

[ericmoritz]

My motivation for bundling it is that I didn't want to force a certain version on people. I also felt like adding a new system dependency is a backwards-incompatible change that I didn't want to make for a minor version update.

By namespacing it under micromodels.packages, someone can install any version of PySO8601 and import that version using:

 import PySO8601

The two versions can live together within one python environment without conflict.

That being said, I am not married to the requests style bundling and can be swayed away from it.

[ericmoritz]

Ok, I see the benefit to non-bundling and I agree. I am going to create a 0.6.0 version that does not bundle PySO8601.

[JNRowe]

Excellent! And, thanks for looking in to this.