Merge lp:~jelmer/bzr-builddeb/opt-distro-info into lp:bzr-builddeb

[Jelmer Vernooij]

Drop python-distro-info from a hard dependency to a recommendation.

This makes porting a bit easier, since distro-info isn't available on e.g. lucid.

This change also defers the import, so that most operations that involved bzr-builddeb don't have to import distro_info and parse the relevant files.

=== modified file 'debian/changelog'
--- debian/changelog	2012-01-30 13:38:04 +0000
+++ debian/changelog	2012-02-01 12:38:21 +0000
@@ -1,8 +1,10 @@
 bzr-builddeb (2.8.3) UNRELEASED; urgency=low
 
   * Fix patch unapplying from DirStateRevisionTrees. LP: #923688
+  * Bump distro-info dependency back to a recommends, to ease
+    backporting.
 
- -- Jelmer Vernooij <[e-mail]>  Mon, 30 Jan 2012 14:37:51 +0100
+ -- Jelmer Vernooij <[e-mail]>  Wed, 01 Feb 2012 13:20:49 +0100
 
 bzr-builddeb (2.8.2) unstable; urgency=low
 
 
=== modified file 'debian/control'
--- debian/control	2012-01-16 02:08:24 +0000
+++ debian/control	2012-02-01 12:38:21 +0000
@@ -12,8 +12,8 @@
 
 Package: bzr-builddeb
 Architecture: all
-Depends: bzr (>= 2.1~), python-debian (>= 0.1.11), python-apt, ${python:Depends}, dpkg-dev, fakeroot, devscripts (>= 2.10.59), patchutils, pristine-tar, ${misc:Depends}, python-distro-info
-Recommends: python-launchpadlib, libalgorithm-merge-perl
+Depends: bzr (>= 2.1~), python-debian (>= 0.1.11), python-apt, ${python:Depends}, dpkg-dev, fakeroot, devscripts (>= 2.10.59), patchutils, pristine-tar, ${misc:Depends}
+Recommends: python-launchpadlib, libalgorithm-merge-perl, python-distro-info
 Suggests: bzr-svn (>= 0.4.10), python-lzma
 Provides: bzr-buildpackage
 Description: bzr plugin for Debian package management
 
=== modified file 'util.py'
--- util.py	2012-01-05 16:09:21 +0000
+++ util.py	2012-02-01 12:38:21 +0000
@@ -29,8 +29,6 @@
 import os
 import re
 
-from distro_info import DebianDistroInfo, UbuntuDistroInfo
-
 from bzrlib.trace import mutter
 
 try:
@@ -76,11 +74,36 @@
     UnparseableChangelog,
     )
 
-
-DEBIAN_RELEASES = DebianDistroInfo().all
-DEBIAN_RELEASES.extend(['stable', 'testing', 'unstable', 'frozen'])
+_DEBIAN_RELEASES = None
+_UBUNTU_RELEASES = None
+
+def _get_release_names():
+    try:
+        from distro_info import DebianDistroInfo, UbuntuDistroInfo
+    except ImportError:
+        warning("distro_info not available. Unable to retrieve current "
+            "list of releases.")
+        _DEBIAN_RELEASES = []
+        _UBUNTU_RELEASES = []
+    else:
+        # distro info is not available
+        _DEBIAN_RELEASES = DebianDistroInfo().all
+        _UBUNTU_RELEASES = UbuntuDistroInfo().all
+
+    _DEBIAN_RELEASES.extend(['stable', 'testing', 'unstable', 'frozen'])
+
+
+def debian_releases():
+    if _DEBIAN_RELEASES is None:
+        _get_release_names()
+    return _DEBIAN_RELEASES
+
+def ubuntu_releases():
+    if _UBUNTU_RELEASES is None:
+        _get_release_names()
+    return _UBUNTU_RELEASES
+
 DEBIAN_POCKETS = ('', '-security', '-proposed-updates', '-backports')
-UBUNTU_RELEASES = UbuntuDistroInfo().all
 UBUNTU_POCKETS = ('', '-proposed', '-updates', '-security', '-backports')
 
 
@@ -246,8 +269,8 @@
     :return: "debian", "ubuntu", or None if the distribution couldn't be
         inferred.
     """
-    all_debian = [r + t for r in DEBIAN_RELEASES for t in DEBIAN_POCKETS]
-    all_ubuntu = [r + t for r in UBUNTU_RELEASES for t in UBUNTU_POCKETS]
+    all_debian = [r + t for r in debian_releases() for t in DEBIAN_POCKETS]
+    all_ubuntu = [r + t for r in ubuntu_releases() for t in UBUNTU_POCKETS]
     if suite in all_debian:
         return "debian"
     if suite in all_ubuntu:
@@ -616,12 +639,12 @@
     :raise NoPreviousUpload: Raised when there is no previous upload
     """
     current_target = find_last_distribution(cl)
-    all_debian = [r + t for r in DEBIAN_RELEASES for t in DEBIAN_POCKETS]
-    all_ubuntu = [r + t for r in UBUNTU_RELEASES for t in UBUNTU_POCKETS]
+    all_debian = [r + t for r in debian_releases() for t in DEBIAN_POCKETS]
+    all_ubuntu = [r + t for r in ubuntu_releases() for t in UBUNTU_POCKETS]
     if current_target in all_debian:
         match_targets = (current_target,)
     elif current_target in all_ubuntu:
-        match_targets = UBUNTU_RELEASES
+        match_targets = ubuntu_releases()
         if "-" in current_target:
             match_targets += tuple([current_target.split("-", 1)[0]
                 + t for t in UBUNTU_POCKETS])