Change 3affcaa2b8 attempts to reset
purelib & platlib to any "install-dir" specified by the user in
setup.cfg. This code is used when we are installing wheels.
The problem with this is that distutils is *always* setting
"i.install_lib" -- even when the user specifies nothing. This has the
result of unconditionally setting purelib == platlib.
On some systems this results in .so's from the wheel getting installed
into /usr/lib/python2.7 (purelib) rather than /usr/lib64/python
(platlib). Because distribution-packaged libraries have installed
their .so into platlib, we can now have a situation where the new
pip-installed library is picking up an old .so from the distro package
... with predictably bad results.
This takes the approach of checking the configuration to see if the
user has overridden install-dir and only resetting the paths if they
have. The override case is covered by existing test-cases.
Closes#2940
before building wheels. Warning is copied from http cache check.
HTTP cache has a similar check and warning,
but wheels would still try and fail to build.
Fixes bug #2683
There are two changes here; one to fix the using-wheels codepath and one
to fix the no-wheels codepath. Two tests are introduced, one to test
each codepath.
Previously we attempt to do some crazy things with import hooks
in order to attempt to automatically alias normally installed
dependencies as our vendored dependencies. This turned out to be
fairly fragile, so instead we'll manually patch sys.modules to
trigger the aliasing.
As part of this, we also drop support for the
PIP_NO_VENDOR_FOR_DOWNSTREAM environment variable because it was
never fully supported and now that we have wheel caching, actually
using it could possibly trigger a bad wheel to be cached. The new
mechanism requires some light patching by downstream to opt into
the mechanism, so they can also easily remove all of the files
in pip/_vendor/ except for __init__.py.
If a single package is listed as a constraint; is a dependency of a
package being installed; *and* is already installed, we end up
processing it multiple times. This change adds a new "prepared" flag
which we set the first time the package is processed, to prevent
multiple handling.
Fixes bug #2888
