From 6fce4a9c3dac5704eeba2e17b4bf023f930542c2 Mon Sep 17 00:00:00 2001
From: fabios <fabios@nationalfibre.net>
Date: Thu, 25 Dec 2014 14:14:01 -0500
Subject: [PATCH 1/4] handle list of list for python-apt < 0.7.9 compatibility

---
 packaging/os/apt.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packaging/os/apt.py b/packaging/os/apt.py
index 43a7d6b390b..7eba3432e60 100644
--- a/packaging/os/apt.py
+++ b/packaging/os/apt.py
@@ -180,7 +180,8 @@ def package_versions(pkgname, pkg, pkg_cache):
         # assume older version of python-apt is installed
         # apt.package.Package#versions require python-apt >= 0.7.9.
         pkg_cache_list = (p for p in pkg_cache.Packages if p.Name == pkgname)
-        pkg_versions = (p.VersionList for p in pkg_cache_list)
+        pkg_list_of_lists = (p.VersionList for p in pkg_cache_list)
+        pkg_versions = (p for l in pkg_list_of_lists for p in l)
         versions = set(p.VerStr for p in pkg_versions)
 
     return versions

From d19f7c702613b73154c40b40ebf6bdcd06745615 Mon Sep 17 00:00:00 2001
From: fabios <fabios@nationalfibre.net>
Date: Sat, 27 Dec 2014 15:30:56 -0500
Subject: [PATCH 2/4] older python-apt compatibility

---
 packaging/os/apt.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/packaging/os/apt.py b/packaging/os/apt.py
index 7eba3432e60..d1101bc7b8b 100644
--- a/packaging/os/apt.py
+++ b/packaging/os/apt.py
@@ -202,8 +202,12 @@ def package_status(m, pkgname, version, cache, state):
         ll_pkg = cache._cache[pkgname] # the low-level package object
     except KeyError:
         if state == 'install':
-            if cache.get_providing_packages(pkgname):
-                return False, True, False
+            try:
+                if cache.get_providing_packages(pkgname):
+                    return False, True, False
+            except AttributeError:
+                # older python-apt providing packages cannot be used
+                pass
             m.fail_json(msg="No package matching '%s' is available" % pkgname)
         else:
             return False, False, False

From b747d9411ac346835c4a38dbe3997c72c0e78137 Mon Sep 17 00:00:00 2001
From: fabios <fabios@nationalfibre.net>
Date: Sat, 27 Dec 2014 21:19:00 -0500
Subject: [PATCH 3/4] improve fail message and use itertools chain

---
 packaging/os/apt.py | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/packaging/os/apt.py b/packaging/os/apt.py
index d1101bc7b8b..77f1e431b2f 100644
--- a/packaging/os/apt.py
+++ b/packaging/os/apt.py
@@ -144,6 +144,7 @@
 import os
 import datetime
 import fnmatch
+import itertools
 
 # APT related constants
 APT_ENV_VARS = dict(
@@ -180,9 +181,8 @@ def package_versions(pkgname, pkg, pkg_cache):
         # assume older version of python-apt is installed
         # apt.package.Package#versions require python-apt >= 0.7.9.
         pkg_cache_list = (p for p in pkg_cache.Packages if p.Name == pkgname)
-        pkg_list_of_lists = (p.VersionList for p in pkg_cache_list)
-        pkg_versions = (p for l in pkg_list_of_lists for p in l)
-        versions = set(p.VerStr for p in pkg_versions)
+        pkg_versions = (p.VersionList for p in pkg_cache_list)
+        versions = set(p.VerStr for p in itertools.chain(*pkg_versions))
 
     return versions
 
@@ -205,10 +205,10 @@ def package_status(m, pkgname, version, cache, state):
             try:
                 if cache.get_providing_packages(pkgname):
                     return False, True, False
+                m.fail_json(msg="No package matching '%s' is available" % pkgname)
             except AttributeError:
-                # older python-apt providing packages cannot be used
-                pass
-            m.fail_json(msg="No package matching '%s' is available" % pkgname)
+                # python-apt version too old to detect virtual packages
+                m.fail_json(msg="No package matching '%s' is available (python-apt version too old to detect virtual packages)" % pkgname)
         else:
             return False, False, False
     try:

From 9ed842e2d0442112f3674dd4ab063e33d70c0254 Mon Sep 17 00:00:00 2001
From: fabios <fabios@nationalfibre.net>
Date: Sun, 28 Dec 2014 12:52:48 -0500
Subject: [PATCH 4/4] mark as upgradable and let apt-get install deal with it

---
 packaging/os/apt.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packaging/os/apt.py b/packaging/os/apt.py
index 77f1e431b2f..ad1807f9c20 100644
--- a/packaging/os/apt.py
+++ b/packaging/os/apt.py
@@ -208,7 +208,8 @@ def package_status(m, pkgname, version, cache, state):
                 m.fail_json(msg="No package matching '%s' is available" % pkgname)
             except AttributeError:
                 # python-apt version too old to detect virtual packages
-                m.fail_json(msg="No package matching '%s' is available (python-apt version too old to detect virtual packages)" % pkgname)
+                # mark as upgradable and let apt-get install deal with it
+                return False, True, False
         else:
             return False, False, False
     try: