Add missing error logging in WheelBuilder

[sbidoul]

Further simplify WheelBuilder.build(), and add a missing error report.

[chrahunt]

The previous implementation had one important feature: it would fail before the wheel build (which can take some time). Maybe _build_one would be a good place to put this?

[pradyunsg]

feature: it would fail before the wheel build

That's a good thing IMO and we should add a test for this.

[sbidoul]

Note this particular directory is going to be inside the cache directory.

When trying pip wheel with a non-writable cache directory, one gets WARNING: The directory '/tmp/cache/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag..

So it looks like checking that the main conditions for this particular ensure_dir to succeed are checked beforehand and it would fail only in very rare situations. So I'd think this particular optimization and test is maybe not worth the additional code?

[sbidoul]

Hm, despite saying the cache is disabled, it attempts to use it nevertheless:

WARNING: The directory '/tmp/cache/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Collecting odoo-autodiscover
  Downloading odoo-autodiscover-2.0.0.tar.gz (16 kB)
Collecting wrapt
  Downloading wrapt-1.11.2.tar.gz (27 kB)
Building wheels for collected packages: odoo-autodiscover, wrapt
  Building wheel for odoo-autodiscover (setup.py) ... done
  WARNING: Building wheel for odoo-autodiscover failed: [Errno 13] Permission denied: 'cache/wheels'
  Running setup.py clean for odoo-autodiscover
  Building wheel for wrapt (setup.py) ... done
  WARNING: Building wheel for wrapt failed: [Errno 13] Permission denied: 'cache/wheels'
  Running setup.py clean for wrapt
Failed to build odoo-autodiscover wrapt
ERROR: Failed to build one or more wheels

[sbidoul]

Because the ownership/writeability check is done for the http cache and not the wheel cache.

[chrahunt]

Small comment, otherwise this LGTM.

[sbidoul]

Thanks!

[pradyunsg]

LGTM -- thanks @sbidoul and @chrahunt! ^>^