Handle multiple requirements for one package

[aababilov]

Sometimes a developer needs to install dependencies for several packages, and each of them has its own requirements.txt file. A good example can be OpenStack - a Python project that has the largest open source community.

Often, the same package is referenced in several files, possibly with different version requirements:

$ cat a/requirements.txt
prettytable>=0.6
$ cat b/requirements.txt
prettytable<0.8

pip should install prettytable>=0.6,<0.8, but it will just complain:

$ pip install -r a/requirements.txt -r b/requirements.txt
Double requirement given: prettytable<0.8 (from -r b/requirements.txt (line 1)) (already in prettytable>=0.6 (from -r a/requirements.txt (line 1)), name='prettytable')

My patch fixes the problem:

pip install -r a/requirements.txt -r b/requirements.txt
Downloading/unpacking prettytable>=0.6,<0.8 (from aggregated requirements)
Downloading prettytable-0.7.2.zip
...

[pfmoore]

It looks like your patch does not work on Python 3 (I noticed a use of dict.iteritems, which is no longer available in Python 3).

[aababilov]

Ok, let's use six

[aababilov]

It seems that the test job is broken by itself.

[aababilov]

@carljm

[aababilov]

@gd-imelnikov

[dstufft]

I'll take a look at this later this week.

[piotr-dobrogost]

This is duplicate of issue #56

[msabramo]

Didn't review the code in detail but the feature sounds useful.

[xavfernandez]

From I quickly glanced, this PR also needs extra work to deal with the new PEP440 specifiers.
Using the packaging.specifiers could help.

[rbtcollins]

I don't like that this needs an option - pip should just adjust the proposed thing, probably needs a state saving backtracker to boot.

[dstufft]

Accidentally closed this, reopening. Sorry!

[BrownTruck]

Hello!

As part of an effort to ease the contribution process and adopt a more standard workflow pip has switched to doing development on the master branch. However, this Pull Request was made against the develop branch so it will need to be resubmitted against master. Unfortunately, this pull request does not cleanly merge against the current master branch.

If you do nothing, this Pull Request will be automatically closed by @BrownTruck since it cannot be merged.

If this pull request is still valid, please rebase it against master (or merge master into it) and resubmit it against the master branch, closing and referencing the original Pull Request.

If you choose to rebase/merge and resubmit this Pull Request, here is an example message that you can copy and paste:

Sometimes a developer needs to install dependencies for several packages, and each of them has its own requirements.txt file. A good example can be OpenStack - a Python project that has the largest open source community.

Often, the same package is referenced in several files, possibly with different version requirements:

$ cat a/requirements.txt
prettytable>=0.6
$ cat b/requirements.txt
prettytable<0.8

pip should install prettytable>=0.6,<0.8, but it will just complain:

$ pip install -r a/requirements.txt -r b/requirements.txt 
Double requirement given: prettytable<0.8 (from -r b/requirements.txt (line 1)) (already in prettytable>=0.6 (from -r a/requirements.txt (line 1)), name='prettytable')

My patch fixes the problem:

pip install -r a/requirements.txt -r b/requirements.txt 
Downloading/unpacking prettytable>=0.6,<0.8 (from aggregated requirements)
  Downloading prettytable-0.7.2.zip
...

---

*This was migrated from pypa/pip#1073 to reparent it to the ``master`` branch. Please see original pull request for any previous discussion.*

[BrownTruck]

This Pull Request was closed because it cannot be automatically reparented to the master branch and it appears to have bit rotted.

Please feel free to re-open it or re-submit it if it is still valid and you have rebased it onto master or merged master into it.