Merge lp:~barry/ubuntu-release-upgrader/lp1485093 into lp:ubuntu-release-upgrader

[Barry Warsaw]

This fixes the imports to not be relative so that it's okay if the symlinks don't exist. Don't create the symlinks in the package install because if the dependent packages aren't installed, the symlinks will be dangling which breaks other packages, specifically pex's build.

Instead, just handle the ImportErrors that can happen if the dependent packages, imported via absolute path, don't exist.

[Brian Murray (brian-murray)]

This looks fine although, and I'll merge it at the start of X.

=== modified file 'DistUpgrade/DistUpgradeCache.py'
--- DistUpgrade/DistUpgradeCache.py	2015-01-20 22:30:06 +0000
+++ DistUpgrade/DistUpgradeCache.py	2015-10-20 20:08:36 +0000
@@ -501,7 +501,7 @@
         # if the free drivers would give us a equally hard time, we would
         # never be able to release
         try:
-            from .NvidiaDetector.nvidiadetector import NvidiaDetection
+            from NvidiaDetector.nvidiadetector import NvidiaDetection
         except (ImportError, SyntaxError) as e:
             # SyntaxError is temporary until the port of NvidiaDetector to
             # Python 3 is in the archive.
 
=== modified file 'DistUpgrade/DistUpgradeQuirks.py'
--- DistUpgrade/DistUpgradeQuirks.py	2015-01-20 22:44:02 +0000
+++ DistUpgrade/DistUpgradeQuirks.py	2015-10-20 20:08:36 +0000
@@ -32,7 +32,16 @@
 from .utils import get_arch
 
 from .DistUpgradeGettext import gettext as _
-from .janitor.plugincore.manager import PluginManager
+try:
+    from janitor.plugincore.manager import PluginManager
+except ImportError:
+    # janitor is not available, so create a no-op plugin manager.
+    class PluginManager(object):
+        def __init__(self, *args, **kws):
+            pass
+
+        def get_plugins(self, *args, **kws):
+            return []
 
 
 class DistUpgradeQuirks(object):
 
=== modified file 'debian/changelog'
--- debian/changelog	2015-10-20 15:56:29 +0000
+++ debian/changelog	2015-10-20 20:08:36 +0000
@@ -1,3 +1,13 @@
+ubuntu-release-upgrader (1:15.10.14) wily; urgency=medium
+
+  * Don't try to import janitor and NvidiaDetector in a package relative
+    to this one, to avoid the possibility of dangling symlinks when the
+    packages actually containing these modules is not installed.
+    (LP: #1485093)
+  * debian/python3-distupgrade.links: Removed.
+
+ -- Barry Warsaw <[e-mail]>  Fri, 16 Oct 2015 17:51:27 -0400
+
 ubuntu-release-upgrader (1:15.10.13) wily; urgency=medium
 
   * Revert change from 15.10.11, already rejected from wily-proposed
 
=== removed file 'debian/python3-distupgrade.links'
--- debian/python3-distupgrade.links	2012-07-13 17:51:44 +0000
+++ debian/python3-distupgrade.links	1970-01-01 00:00:00 +0000
@@ -1,2 +0,0 @@
-usr/lib/python3/dist-packages/janitor usr/lib/python3/dist-packages/DistUpgrade/janitor
-usr/lib/python3/dist-packages/NvidiaDetector usr/lib/python3/dist-packages/DistUpgrade/NvidiaDetector