Debian Janitor: > 60,000 Lintian Issues Automatically Fixed

The Debian Janitor is an automated system that commits fixes for (minor) issues in Debian packages that can be fixed by software. It gradually started proposing merges in early December. The first set of changes sent out ran lintian-brush on sid packages maintained in Git. This post is part of a series about the progress of the Janitor.

Scheduling Lintian Fixes

To determine which packages to process, the Janitor looks at the import of lintian output across the archive that is available in UDD [1]. It will prioritize those packages with the most and more severe issues that it has fixers for.

Once a package is selected, it will clone the packaging repository and run lintian-brush on it. Lintian-brush provides a framework for applying a set of “fixers” to a package. It will run each of a set of “fixers” in a pristine version of the repository, and handles most of the heavy lifting.

The Inner Workings of a Fixer

Each fixer is just an executable which gets run in a clean checkout of the package, and can make changes there. Most of the fixers are written in Python or shell, but they can be in any language.

The contract for fixers is pretty simple:

  • If the fixer exits with non-zero, the changes are reverted and fixer is considered to have failed
  • If it exits with zero and made changes, then it should write a summary of its changes to standard out

If a fixer is uncertain about the changes it has made, it should report so on standard output using a pseudo-header. By default, lintian-brush will discard any changes with uncertainty but if you are running it locally you can still apply them by specifying --uncertain.

The summary message on standard out will be used for the commit message and (possibly) the changelog message, if the package doesn’t use gbp dch.

Example Fixer

Let’s look at an example. The package priority “extra” is deprecated since Debian Policy 4.0.1 (released August 2 017) – see Policy 2.5 "Priorities". Instead, most packages should use the “optional” priority.

Lintian will warn when a package uses the deprecated “extra” value for the “Priority” - the associated tag is priority-extra-is-replaced-by-priority-optional. Lintian-brush has a fixer script that can automatically replace “extra” with “optional”.

On systems that have lintian-brush installed, the source for the fixer lives in /usr/share/lintian-brush/fixers/priority-extra-is-replaced-by-priority-optional.py, but here is a copy of it for reference:

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#!/usr/bin/python3

from debmutate.control import ControlEditor
from lintian_brush.fixer import report_result, fixed_lintian_tag

with ControlEditor() as updater:
    for para in updater.paragraphs:
        if para.get("Priority") == "extra":
            para["Priority"] = "optional"
            fixed_lintian_tag(
                para, 'priority-extra-is-replaced-by-priority-optional')

report_result("Change priority extra to priority optional.")

This fixer is written in Python and uses the debmutate library to easily modify control files while preserving formatting — or back out if it is not possible to preserve formatting.

All the current fixers come with tests, e.g. for this particular fixer the tests can be found here: https://salsa.debian.org/jelmer/lintian-brush/-/tree/master/tests/priority-extra-is-replaced-by-priority-optional.

For more details on writing new fixers, see the README for lintian-brush.

For more details on debugging them, see the manual page.

Successes by fixer

Here is a list of the fixers currently available, with the number of successful merges/pushes per fixer:

Lintian Tag Previously merged/pushed Ready but not yet merged/pushed
uses-debhelper-compat-file 4906 4161
upstream-metadata-file-is-missing 4281 3841
package-uses-old-debhelper-compat-version 4256 3617
upstream-metadata-missing-bug-tracking 2438 2995
out-of-date-standards-version 2062 2936
upstream-metadata-missing-repository 1936 2987
trailing-whitespace 1720 2295
insecure-copyright-format-uri 1791 1093
package-uses-deprecated-debhelper-compat-version 1391 1287
vcs-obsolete-in-debian-infrastructure 872 782
homepage-field-uses-insecure-uri 527 1111
vcs-field-not-canonical 850 655
debian-changelog-has-wrong-day-of-week 224 376
debian-watch-uses-insecure-uri 314 242
useless-autoreconf-build-depends 112 428
priority-extra-is-replaced-by-priority-optional 315 194
debian-rules-contains-unnecessary-get-orig-source-target 35 428
tab-in-license-text 125 320
debian-changelog-line-too-long 186 190
debian-rules-sets-dpkg-architecture-variable 69 166
debian-rules-uses-unnecessary-dh-argument 42 182
package-lacks-versioned-build-depends-on-debhelper 125 95
unversioned-copyright-format-uri 43 136
package-needs-versioned-debhelper-build-depends 127 50
binary-control-field-duplicates-source 34 134
renamed-tag 73 69
vcs-field-uses-insecure-uri 14 109
uses-deprecated-adttmp 13 91
debug-symbol-migration-possibly-complete 12 88
copyright-refers-to-symlink-license 51 48
debian-control-has-unusual-field-spacing 33 66
old-source-override-location 32 62
out-of-date-copyright-format 20 62
public-upstream-key-not-minimal 43 30
older-source-format 17 54
custom-compression-in-debian-source-options 12 57
copyright-refers-to-versionless-license-file 29 39
tab-in-licence-text 33 31
global-files-wildcard-not-first-paragraph-in-dep5-copyright 28 33
out-of-date-copyright-format-uri 9 50
field-name-typo-dep5-copyright 29 29
copyright-does-not-refer-to-common-license-file 13 42
debhelper-but-no-misc-depends 9 45
debian-watch-file-is-missing 11 41
debian-control-has-obsolete-dbg-package 8 40
possible-missing-colon-in-closes 31 13
unnecessary-testsuite-autopkgtest-field 32 9
missing-debian-source-format 7 33
debhelper-tools-from-autotools-dev-are-deprecated 9 29
vcs-field-mismatch 8 29
debian-changelog-file-contains-obsolete-user-emacs-setting 33 0
patch-file-present-but-not-mentioned-in-series 24 9
copyright-refers-to-versionless-license-file 22 9
debian-control-has-empty-field 25 6
missing-build-dependency-for-dh-addon 10 20
obsolete-field-in-dep5-copyright 15 13
xs-testsuite-field-in-debian-control 20 7
ancient-python-version-field 13 12
unnecessary-team-upload 19 5
misspelled-closes-bug 6 16
field-name-typo-in-dep5-copyright 1 20
transitional-package-not-oldlibs-optional 4 17
maintainer-script-without-set-e 9 11
dh-clean-k-is-deprecated 4 14
no-dh-sequencer 14 4
missing-vcs-browser-field 5 12
space-in-std-shortname-in-dep5-copyright 6 10
xc-package-type-in-debian-control 4 11
debian-rules-missing-recommended-target 4 10
desktop-entry-contains-encoding-key 1 13
build-depends-on-obsolete-package 4 9
license-file-listed-in-debian-copyright 1 12
missing-built-using-field-for-golang-package 9 4
unused-license-paragraph-in-dep5-copyright 4 7
missing-build-dependency-for-dh_command 6 4
comma-separated-files-in-dep5-copyright 3 6
systemd-service-file-refers-to-var-run 4 5
copyright-not-using-common-license-for-apache2 3 5
debian-tests-control-autodep8-is-obsolete 2 6
dh-quilt-addon-but-quilt-source-format 2 6
no-homepage-field 3 5
font-packge-not-multi-arch-foreign 1 6
homepage-in-binary-package 1 4
vcs-field-bitrotted 1 3
built-using-field-on-arch-all-package 2 1
copyright-should-refer-to-common-license-file-for-apache-2 1 2
debian-pyversions-is-obsolete 3 0
debian-watch-file-uses-deprecated-githubredir 1 1
executable-desktop-file 1 1
skip-systemd-native-flag-missing-pre-depends 1 1
vcs-field-uses-not-recommended-uri-format 1 1
init.d-script-needs-depends-on-lsb-base 1 0
maintainer-also-in-uploaders 1 0
public-upstream-keys-in-multiple-locations 1 0
wrong-debian-qa-group-name 1 0
Total 29656 32209

Footnotes

[1]temporarily unavailable due to Debian bug #960156 – but the Janitor is relying on historical data

For more information about the Janitor's lintian-fixes efforts, see the landing page.

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