Environment is not recreated when install_requires in setup.py is changed

[pytoxbot]

• Bitbucket: https://bitbucket.org/hpk42/tox/issue/93
• Originally reported by: @tkf
• Originally created at: 2013-04-15T22:07:44.806

Here is a recipe to reproduce this problem.

1. Run tox in some project.
2. Add a new package to install_requires in setup.py
3. Run tox again.

I can write dependency in tox.ini to force recreate, but I think it is simpler if tox reinstall package. I think it is as easy as removing --no-deps flag so I wonder why --no-deps is used in the first place. Is there any drawbacks? Wouldn't it be nice if we can disable this flag optionally?

[pytoxbot]

Original comment by @graingert

pull request #64 should help with this:

simply configure your setup.py to pull install_requires out of requirements.txt, and set the deps to -r{toxinidir}requirements.txt

[pytoxbot]

Original comment by @graingert

You also get the same problem if -r{toxinidir}requirements.txt is used

[pytoxbot]

Original comment by @graingert

Might be an idea to use https://pypi.python.org/pypi/pip-accel

[pytoxbot]

Original comment by @tkf

@lukaszb If you are running tox manually then --recreate is perfect. But how about when you are using it in Jenkins, for example?

@hpk42 I think that's more accurate solution and I like that.

[pytoxbot]

Original comment by @hpk42

Maybe we could do a "setup.py egg_info" if "setuptools" appears in setup.py and then fish for *.egg-info/requirements.txt to get to know the deps. This would still allow changing other aspects of setup.py without recreating automatically the venv.

[pytoxbot]

Original comment by @lukaszb

I would vote against it.

Passing --recreate flag seems good enough. I often tinker setup.py file without touching deps at all and if I do, I actually know about it most of the time.

[pytoxbot]

Original comment by @hpk42

we could probably do a checksum of the setup.py and run a full (no --no-deps) install if it changes. There is no direct general way to just get the install_requires content out of it.

[pytoxbot]

Original comment by @tkf

Can't we detect requirements before running pip? Or how about caching setup.py (or compare timestamp or checksum) and reinstall it without --no-deps when it is changed?

[pytoxbot]

Original comment by @hpk42

Some time ago someone else complained that reinstalling a package would always re-install the dependencies, increasing overall run time. Changing install_requires is a relatively rare event -- can you not issue --recreate on this occassion?

[pytoxbot]

Original comment by @tkf

I guess a simple solution is to put the following in the first entry of commands

pip install --quiet --use-mirrors {toxinidir} --log {envtmpdir}/pip.log

[obestwalter]

Reading through this my impression is that the existing functionality is already enough and the opinions differ if and how this should be solved.

I would tend to close this as wontfix soonish - any objections?

[graingert]

Actually it's not too hard to inspect the requirements of a package via setuptools

[RonnyPfannschmidt]

@graingert actually its nondetermistic and broken to try and do so with just setuptools ^^

the amount of logic, sandboxing &more pip adds around to keep things sane is hard to copy

[Varriount]

@obestwalter I just ran into this issue recently, and it strikes me as very unexpected behavior.
When I run tox, I expect all my changes - documentation, code, etc - to be incorporated in the environments managed by tox. I tend to think of setup.py as just another python file in the project.

At the very least, the documentation needs to explicitly mention this behavior. Ideally python setup.py --requires would also print out the install_requires input, but it prints out packages fed into requires instead (is requires even used anymore?).

[obestwalter]

At the very least, the documentation needs to explicitly mention this behavior.

I agree, that is the least we can do.