From 9a6b6240d0befaa2efd5578e9d3a3ce5a539109d Mon Sep 17 00:00:00 2001
From: Adrian Sampson <adrian@radbox.org>
Date: Sat, 1 Jun 2013 17:28:59 -0700
Subject: [PATCH] zero: fix nulling fields containing None

---
 beetsplug/zero.py  | 3 ++-
 docs/changelog.rst | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/beetsplug/zero.py b/beetsplug/zero.py
index ef0b8b28d..1ea6d0e50 100644
--- a/beetsplug/zero.py
+++ b/beetsplug/zero.py
@@ -89,6 +89,7 @@ class ZeroPlugin(BeetsPlugin):
                     continue
                 self._log.debug(u'[zero] \"{0}\" ({1}) match: {2}'
                                 .format(fval, fn, ' '.join(patterns)))
-                setattr(item, fn, type(fval)())
+                new_val = None if fval is None else type(fval)()
+                setattr(item, fn, new_val)
                 self._log.debug(u'[zero] {0}={1}'
                                 .format(fn, getattr(item, fn)))
diff --git a/docs/changelog.rst b/docs/changelog.rst
index eeeb78d86..f602ca744 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -47,6 +47,8 @@ Changelog
   that go missing.
 * The :ref:`modify-cmd` command can now change albums' album art paths (i.e.,
   ``beet modify artpath=...`` works). Thanks to Lucas Duailibe.
+* :doc:`/plugins/zero`: Fix a crash when nulling out a field that contains
+  None.
 * Various UI enhancements to the importer due to Tai Lee:
 
   * More consistent format and colorization of album and track metadata.