flaskr project (in dev docs and on github) needs to use relative import in __init__.py for Python 3

[toddjames]

Currently, while following the dev docs or cloning the existing flaskr project on GitHub, it will not run in a Python 3 virtualenv. The error when running the cloned flaskr application is:

Traceback (most recent call last): File "/home/todd/flaskr/flask/examples/flaskr/env/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise raise value File "/home/todd/flaskr/flask/examples/flaskr/flaskr/__init__.py", line 1, in <module> from flaskr import app ImportError: cannot import name 'app'

This is the same error when following the docs to recreate the flaskr application. By modifying flaskr/__init__.py to include a relative import when using a Python 3 virtualenv, everything works fine.

That is, in flaskr/__init__.py, change:
from flaskr import app
to:
from .flaskr import app

(note the period)

At this point, I am still not comfortable contributing, nor do I know if this is the correct solution or if this has any implications for Python 2. Hence the issue, hoping someone else can confirm this is correct, or provide a better solution.

[wgwz]

Good catch, this is my mistake. That line should be from flaskr.flaskr import app. Does this import statement fix it for you?

[toddjames]

Yes, that also fixes it.

[toddjames]

Thanks for the quick fix to the project itself. You may want to fix the documentation on this page, too:

http://flask.pocoo.org/docs/dev/tutorial/packaging/#tutorial-packaging

[untitaker]

That should eventually update automatically.

[wgwz]

@untitaker Are there tools available to link parts of a code example to documentation? That would be quite nice.

[untitaker]

What do you mean?

[untitaker]

Are you talking about the examples directory in the repo, or inline code examples?

[georgeberry]

I found this error as well. This is my (working) __init__.py file:

from flask import Flask
app = Flask(__name__)

from . import views # relative import to fix github issue #2058