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Issue #20812: Add a short opener to the Python 2/3 porting HOWTO. 

Thanks to Nick Coghlan for the suggestion.
This commit is contained in:
Brett Cannon 2014-03-07 12:27:10 -05:00
parent 5ccca9516a
commit 6634e15d77
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Doc/howto/pyporting.rst
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@ -26,6 +26,32 @@ Porting Python 2 Code to Python 3
For help with porting, you can email the python-porting_ mailing list with
questions.
The Short Version
=================
* Decide what's the oldest version of Python 2 you want to support (if at all)
* Make sure you have a thorough test suite and use continuous integration
testing to make sure you stay compatible with the versions of Python you care
about
* If you have dependencies, check their Python 3 status using caniusepython3
(`command-line tool <https://pypi.python.org/pypi/caniusepython3>`__,
`web app <https://caniusepython3.com/>`__)
With that done, your options are:
* If you are dropping Python 2 support, use 2to3_ to port to Python 3
* If you are keeping Python 2 support, then start writing Python 2/3-compatible
code starting **TODAY**
+ If you have dependencies that have not been ported, reach out to them to port
their project while working to make your code compatible with Python 3 so
you're ready when your dependencies are all ported
+ If all your dependencies have been ported (or you have none), go ahead and
port to Python 3
* If you are creating a new project that wants to have 2/3 compatibility,
code in Python 3 and then backport to Python 2
Before You Begin
================
@ -548,7 +574,10 @@ Backporting Python 3 code to Python 2
If you have Python 3 code and have little interest in supporting Python 2 you
can use 3to2_ to translate from Python 3 code to Python 2 code. This is only
recommended if you don't plan to heavily support Python 2 users.
recommended if you don't plan to heavily support Python 2 users. Otherwise
write your code for Python 3 and then backport as far back as you want. This
is typically easier than going from Python 2 to 3 as you will have worked out
any difficulties with e.g. bytes/strings, etc.
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