better error message on unreadable database

NEWS

@@ -34,6 +34,7 @@
 * Fix a rare deadlock when finishing the import pipeline.
 * Fix an issue that was causing mpdupdate to run twice for every album.
 * Fix a bug that caused release dates/years not to be fetched.
+* A better error message is given when the database file is unopenable.
 
 1.0b8
 -----

beets/ui/__init__.py

@@ -24,6 +24,7 @@ import ConfigParser
 import sys
 from difflib import SequenceMatcher
 import logging
+import sqlite3
 
 from beets import library
 from beets import plugins
@@ -584,10 +585,14 @@ def main(args=None, configfh=None):
             path_formats.update(config.items('paths'))
     art_filename = \
         config_val(config, 'beets', 'art_filename', DEFAULT_ART_FILENAME)
-    lib = library.Library(os.path.expanduser(libpath),
-                          directory,
-                          path_formats,
-                          art_filename)
+    db_path = os.path.expanduser(libpath)
+    try:
+        lib = library.Library(db_path,
+                              directory,
+                              path_formats,
+                              art_filename)
+    except sqlite3.OperationalError:
+        raise UserError("database file %s could not be opened" % db_path)
     
     # Configure the logger.
     log = logging.getLogger('beets')

test/test_ui.py

@@ -243,6 +243,15 @@ class ConfigTest(unittest.TestCase):
         os.environ['BEETSCONFIG'] = '/xxxxx'
         ui.main(['version'])
 
+    def test_nonexistant_db(self):
+        def func(lib, config, opts, args):
+            pass
+        with self.assertRaises(ui.UserError):
+            self._run_main([], textwrap.dedent("""
+                [beets]
+                library: /xxx/yyy/not/a/real/path
+            """), func)
+
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)