Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Clarify execution order in init #488

Merged
merged 5 commits into from
Feb 9, 2019
+17 −0
Merged

Clarify execution order in init #488

Changes from 1 commit
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
a09ea0e
Clarify execution order in init
hynek Jan 22, 2019
7fb18bc
Clarify attributes are processed in the order of declaration
hynek Jan 23, 2019
8861a32
Simple past is good enough
hynek Jan 23, 2019
dbfa392
Merge branch 'master' into validators-order
hynek Feb 1, 2019
374d991
Merge branch 'master' into validators-order
hynek Feb 8, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 17 additions & 0 deletions docs/init.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -350,6 +350,23 @@ If you need to set attributes on a frozen class, you'll have to resort to the :r

Note that you *must not* access the hash code of the object in ``__attrs_post__init__`` if ``cache_hash=True``.


Order of Execution
------------------

If present, the hooks are executed in the following order:

1. For each attribute:
hynek marked this conversation as resolved.
Show resolved Hide resolved

a. default factory
b. converter

2. *all* validators
3. ``__attrs_post_init__``

Notably this means, that you can access all attributes from within your validators, but your converters have to deal with invalid values and have to return a valid value.


.. _`Wiki page`: https://github.com/python-attrs/attrs/wiki/Extensions-to-attrs
.. _`get confused`: https://github.com/python-attrs/attrs/issues/289
.. _`there is no such thing as a private argument`: https://github.com/hynek/characteristic/issues/6