gmusic: Fix compatibility with gmusicapi>=12.0.0

Fixes #3270.

beetsplug/gmusic.py

@@ -31,12 +31,19 @@ class Gmusic(BeetsPlugin):
     def __init__(self):
         super(Gmusic, self).__init__()
         self.m = Musicmanager()
+
+        # OAUTH_FILEPATH was moved in gmusicapi 12.0.0.
+        if hasattr(Musicmanager, 'OAUTH_FILEPATH'):
+            oauth_file = Musicmanager.OAUTH_FILEPATH
+        else:
+            oauth_file = gmusicapi.clients.OAUTH_FILEPATH
+
         self.config.add({
             u'auto': False,
             u'uploader_id': '',
             u'uploader_name': '',
             u'device_id': '',
-            u'oauth_file': gmusicapi.clients.OAUTH_FILEPATH,
+            u'oauth_file': oauth_file,
         })
         if self.config['auto']:
             self.import_stages = [self.autoupload]

docs/changelog.rst

@@ -12,6 +12,9 @@ Fixes:
 * :doc:`/plugins/gmusic`: The ``oauth_file`` config option now supports more
   flexible path values, including ``~`` for the home directory.
   :bug:`3270`
+* :doc:`/plugins/gmusic`: Fix a crash when using version 12.0.0 or later of
+  the ``gmusicapi`` module.
+  :bug:`3270`
 
 
 1.4.8 (May 16, 2019)