Provide --egg option to opt out --single-version-externally-managed

[k4ml]

Discussion here - #3 (comment)

[travisbot]

This pull request fails (merged 66ff8e0 into e0db44e).

[carljm]

The Travis CI failure is an unrelated intermittent failing test, ignore that, tests pass on this.

Re making this option work via config or env var, good news -- you don't have to do anything, it already works. All pip options automatically work as either env vars (in this case, set PIP_EGG=1) or config file options (egg=1).

I do notice though that there's error output later in the install method because pip can't find where to put its installed-files record. I think we should still include the installed-files record and place it at the top-level inside the unzipped egg. This also means we should use the always-unzip flag when installing as an egg, which I think we should do anyway; I'm not aware of any good justification for installing zipped eggs.

Other than those fixes, this looks ready for merge! Good work, thanks!

[k4ml]

I can't find a clean way to get the egg dir from list of files in record_filename. One I can think of right now:-

diff --git a/pip/req.py b/pip/req.py
index 0e50672..c86030e 100644
--- a/pip/req.py
+++ b/pip/req.py
@@ -595,6 +595,9 @@ exec(compile(open(__file__).read().replace('\\r\\n', '\\n'), _
                 if line.endswith('.egg-info'):
                     egg_info_dir = line
                     break
+                if line.endswith('EGG-INFO/PKG-INFO'):
+                    egg_info_dir = line[:-len('EGG-INFO/PKG-INFO')]
+                    break
             else:
                 logger.warn('Could not find .egg-info directory in install record
                 ## FIXME: put the record somewhere

But since pip now can properly uninstall packages installed by easy_install, do we really need to keep installed-files.txt ? Packages installed with pip install --egg should be no different than the one installed by easy_install.

[carljm]

I'm not totally opposed to just leaving out installed-files.txt, but I think it's better to have a full record of installed files than not, even though that makes the installation slightly different than what easy_install would do. Pip makes a best-effort to uninstall packages installed by easy_install, but without a proper uninstall log it depends on cobbling together various metadata to try to find installed scripts, data files, etc. A real installed-files log takes all the guessing out.

I think finding it should be just as easy as the current code to find the egg-info dir; directories are included too, so we can just look for a line.endswith('.egg') in addition to line.endswith('.egg-info'), right?

[k4ml]

There's no .egg dir in record_filename. Here's list of files that I get when iterating record_filename while installing argparse module:-

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/argparse.py

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/argparse.pyc

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/EGG-INFO/PKG-INFO

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/EGG-INFO/not-zip-safe

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/EGG-INFO/dependency_links.txt

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/EGG-INFO/SOURCES.txt

/home/kamal/python/env/pip/lib/python2.6/site-packages/argparse-1.2.1-py2.6.egg/EGG-INFO/top_level.txt

Also I found out that there's no always--unzip option to setup.py install command:-

http://python.6.n6.nabble.com/setuptools-zip-safe-as-command-line-option-td2003942.html

I've try the workaround setup.py easy_install -Z . as suggested in the thread. It work if I run it from command line but not through pip, it simply said no command easy_install.

[carljm]

Meh, that's unfortunate that there's no --always-unzip for setup.py install. In that case, I think it's just not worth worrying about installed-files.txt. But I would like to get rid of that error, so can you add the appropriate checks so pip doesn't try to look for a place for installed-files.txt when --egg is used?

[k4ml]

Sorry, the commit message a bit wrong. Should be "do not write installed-files.txt if using install --egg".

[travisbot]

This pull request passes (merged becfb83 into e0db44e).