Software-Center crash at launch if apt-history gzip archives are corrupted

Thanks for the report. I can confirm the issue with S-C 3.0.7 in maverick.
The issue was fixed in the trunk at revision 1284, available in S-C ≥ 3.1.1.
We may want to backport the fix to Maverick though, as it is a crasher that renders S-C unusable.

Here is the traceback generated on Maverick:

Traceback (most recent call last):
  File "/usr/bin/software-center", line 90, in <module>
    app = SoftwareCenterApp(datadir, xapian_base_path, options, args)
  File "/usr/share/software-center/softwarecenter/app.py", line 149, in __init__
    self.history = get_apt_history()
  File "/usr/share/software-center/softwarecenter/apt/apthistory.py", line 178, in get_apt_history
    apt_history = AptHistory()
  File "/usr/share/software-center/softwarecenter/apt/apthistory.py", line 83, in __init__
    self.rescan()
  File "/usr/share/software-center/softwarecenter/apt/apthistory.py", line 98, in rescan
    self._scan(history_gz_file)
  File "/usr/share/software-center/softwarecenter/apt/apthistory.py", line 110, in _scan
    for stanza in deb822.Deb822.iter_paragraphs(f):
  File "/usr/lib/pymodules/python2.6/debian/deb822.py", line 287, in iter_paragraphs
    x = cls(iterable, fields, encoding=encoding)
  File "/usr/lib/pymodules/python2.6/debian/deb822.py", line 255, in __init__
    self._internal_parser(sequence, fields)
  File "/usr/lib/pymodules/python2.6/debian/deb822.py", line 308, in _internal_parser
    for line in self.gpg_stripped_paragraph(sequence):
  File "/usr/lib/pymodules/python2.6/debian/deb822.py", line 551, in gpg_stripped_paragraph
    return cls.split_gpg_and_payload(sequence)[1]
  File "/usr/lib/pymodules/python2.6/debian/deb822.py", line 503, in split_gpg_and_payload
    for line in sequence:
  File "/usr/lib/python2.6/gzip.py", line 438, in next
    line = self.readline()
  File "/usr/lib/python2.6/gzip.py", line 393, in readline
    c = self.read(readsize)
  File "/usr/lib/python2.6/gzip.py", line 219, in read
    self._read(readsize)
  File "/usr/lib/python2.6/gzip.py", line 271, in _read
    uncompress = self.decompress.decompress(buf)
zlib.error: Error -3 while decompressing: invalid distance too far back

I’m not sure how to mark the bug as affecting Maverick and fixed in Natty, and it seems I cannot change the bug status now that I’ve marked it 'Fix Released'…
Anyway, I’m attaching a patch against lp:ubuntu/maverick-updates/software-center that fixes the crash.

Heya Olivier! :) Thanks a lot for the patch. I applied it to a branch for 3.0 and nominated this bug for maverick. This is good timing as we have another fix that we need to cherrypick for an SRU as well (bug 684077).

Thanks again!
Gary

Awesome, thanks for your swiftness Gary!

Accepted software-center into maverick-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

I have verified this fix in software-center version 3.0.9 in maverick-proposed per the stated test procedure, and all seems fine. Thanks!

This bug was fixed in the package software-center - 3.0.9

---------------
software-center (3.0.9) maverick-proposed; urgency=low

  [ Gary Lasker ]
  * softwarecenter/db/update.py,
    test/test_appview.py,
    test/test_database.py:
    - track cataloged_time for items not in axi (e.g. for-purchase apps)
      so that they will show up in What's New, add/modify unit tests
      per the changes (LP: #684077)
    - fix icon display that have a "." in it (LP: #745942)
  * softwarecenter/db/update.py,
    softwarecenter/view/appdetailsview_gtk.py,
    test/test_downloader.py:
    - fix screenshot issues for apps for purchase and update unit
      test (LP: #791932)

  [ Olivier Tilloy ]
  * softwarecenter/apt/apthistory.py:
    - fix startup crash if the history file is corrupted (LP: #725186)
 -- Gary Lasker <email address hidden> Wed, 15 Jun 2011 22:35:43 -0400