[Piuparts-devel] Bug#648162: [PATCH v2] use apt-get remove; remove/purge all packages at once

[Andreas Beckmann]

this patch is available from 
  git://github.com/anbe42/piuparts.git feature/648162-apt-get-remove
------ 8< -----
Removing packages with dpkg one-by-one does not respect dependencies
and may fail e.g. when Pre-Depends are involved.  Therefore use
  apt-get remove   on all packages in one run to reorder them properly.
apt-get purge can't be used because it fails on unknown packages (i.e. not
in the archive and not in config-files-remaining state). See #637853.
Also apt-get in lenny is not able to properly purge packages in
config-files-remaining state.
But we can purge all packages in one dpkg call.

The remove_or_purge() method is replaced by two new methods
remove_packages() and purge_packages().

Signed-off-by: Andreas Beckmann <debian at abeckmann.de>
---
 piuparts.py |   25 ++++++++++++++-----------
 1 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/piuparts.py b/piuparts.py
index 4fffbd6..3f22d46 100644
--- a/piuparts.py
+++ b/piuparts.py
@@ -865,12 +865,15 @@ class Chroot:
             vdict[name] = status
         return vdict
 
-    def remove_or_purge(self, operation, packages):
-        """Remove or purge packages in a chroot."""
-        for name in packages:
-            self.run(["dpkg", "--" + operation, name], ignore_errors=True)
-        self.run(["dpkg", "--remove", "--pending"], ignore_errors=True)
+    def remove_packages(self, packages):
+        """Remove packages in a chroot."""
+        if packages:
+            self.run(["apt-get", "remove"] + packages, ignore_errors=True)
 
+    def purge_packages(self, packages):
+        """Purge packages in a chroot."""
+        if packages:
+            self.run(["dpkg", "--purge"] + packages, ignore_errors=True)
  
     def restore_selections(self, changes, packages):
         """Restore package selections in a chroot by applying 'changes'.
@@ -898,8 +901,8 @@ class Chroot:
             self.run_scripts("pre_remove")      
 
         # First remove all packages.
-        self.remove_or_purge("remove", deps_to_remove + deps_to_purge +
-                                        nondeps_to_remove + nondeps_to_purge)
+        self.remove_packages(deps_to_remove + deps_to_purge +
+                             nondeps_to_remove + nondeps_to_purge)
         # Run custom scripts after removing all packages. 
         if settings.scriptsdir is not None:
             self.run_scripts("post_remove")     
@@ -916,13 +919,13 @@ class Chroot:
         if not settings.skip_logrotatefiles_test and logrotatefiles:
             installed = self.install_logrotate()
             self.check_output_logrotatefiles(logrotatefiles_list)
-            self.remove_or_purge("purge", installed)
+            self.purge_packages(installed)
 
         # Then purge all packages being depended on.
-        self.remove_or_purge("purge", deps_to_purge)
+        self.purge_packages(deps_to_purge)
 
         # Finally, purge actual packages.
-        self.remove_or_purge("purge", nondeps_to_purge)
+        self.purge_packages(nondeps_to_purge)
 
         # Run custom scripts after purge all packages.
         if settings.scriptsdir is not None: 
@@ -1718,7 +1721,7 @@ def install_purge_test(chroot, root_info, selections, package_list, packages):
         chroot.install_package_files([metapackage])
         # Now remove it
         metapackagename = os.path.basename(metapackage)[:-4]
-        chroot.remove_or_purge("purge", [metapackagename])
+        chroot.purge_packages([metapackagename])
         shutil.rmtree(os.path.dirname(metapackage))
 
         # Save the file ownership information so we can tell which
-- 
1.7.7.1