Add interpolate option

[David-Wobrock]

The argument is already documented but not implemented yet.
Fixes #415

[WTK]

I believe this doesn't solve the problem I see with the code: when using interpolation and cast together you'll get unexpected error. Minimal example:

# .env file contents:
# BAR=3.2
# FOO=$BAR

import environ
env = environ.Env(interpolate=True)
env.str('FOO') # -- outputs "3.2" as expected
env.float('FOO') # <- errores out, as it tries to make float out of not expanded string literal "BAR"

[David-Wobrock]

Hey @WTK

Thanks for the comment, I think it would be worth creating another PR to fix the issue you are mentioning.
The hereby PR is adding the logic to deactivate the interpolate option, whereas, from what I'm understanding, you are mentioning that interpolation doesn't work properly.

[ThalusA]

@sergeyklay I see you are now the main contributor with push access to this repository, would you mind merging this simple PR ? It just makes interpolate works like it is supposed to be. It doesn't create new errors or anything like that.

[David-Wobrock]

Rebased to fix the conflict.

[coveralls]

coverage: 92.5% (+0.2%) from 92.255% when pulling 8c1b1c1 on David-Wobrock:feat/add-interpolate-option into 2750dd5 on joke2k:develop.

[sergeyklay]

@David-Wobrock I've been looking through your pull request and in principle, everything looks good. However, there seem to be a few builds that failed, notably the code style checks and linters. Could you please make the necessary adjustments? It would greatly assist in maintaining our codebase's quality and readability. Also, I would appreciate it if you could add an entry in the changelog about these changes as well as update corresponding article https://github.com/joke2k/django-environ/blob/main/docs/tips.rst#proxy-value. This would save me some time and ensure that we keep our documentation up to date.

[David-Wobrock]

Hi @sergeyklay

Thanks for your input 👍

However, there seem to be a few builds that failed

I adapted the code ✔️ We should be good now (linting passes locally).
I forced-push, to keep one lean commit, but it seems that the PR requires new approval for running the CI 😕

add an entry in the changelog about these changes

Done ✔️

update corresponding article https://github.com/joke2k/django-environ/blob/main/docs/tips.rst#proxy-value

From my understanding, everything is already documented in the tips section.
That was one of the major reasons of the PR: the logic was documented, but not implemented 😄

[sergeyklay]

Thank you!

[sergeyklay]

@David-Wobrock Thank you for your contribution to the project. Unfortunately, after implementing your interpolation solution, we've encountered issues from our users. Due to this, we've decided to revert your changes and release a patch version.

This is not a reflection on the quality of your code or idea; it's just that it has caused some complications in this particular context.