ext: Fix unpacking of VersionConflict exception

Fixes #911

docs/changelog.rst

@@ -10,12 +10,16 @@ v0.19.5 (UNRELEASED)
 
 Bug fix release.
 
-- config: Support UTF-8 in default config. If an extension with non-ASCII
+- Config: Support UTF-8 in default config. If an extension with non-ASCII
   characters in its default config was installed, and Mopidy didn't already
   have a config file, Mopidy would crashed when trying to create the initial
   config file based on the default config of all available extensions.
   (Fixes: :discuss:`428`)
 
+- Extensions: Fix crash when unpacking data from
+  :exc:`pkg_resources.VersionConflict` created with a single argument. (Fixes:
+  :issue:`911`)
+
 - Models: Hide empty collections from :func:`repr()` representations.
 
 - Models: Field values are no longer stored on the model instance when the

mopidy/ext.py

@@ -188,10 +188,13 @@ def validate_extension(extension):
             extension.ext_name, ex)
         return False
     except pkg_resources.VersionConflict as ex:
-        found, required = ex.args
+        if len(ex.args) == 2:
-        logger.info(
+            found, required = ex.args
-            'Disabled extension %s: %s required, but found %s at %s',
+            logger.info(
-            extension.ext_name, required, found, found.location)
+                'Disabled extension %s: %s required, but found %s at %s',
+                extension.ext_name, required, found, found.location)
+        else:
+            logger.info('Disabled extension %s: %s', extension.ext_name, ex)
         return False
 
     try: