FileOperationError: also include the file path

This makes the errors fully self-descriptive, which simplifies logging them as
errors (you just have to `log.error(exc)` to get a reasonable message). We
also now handle these at the top level in case someone forgets to add a
handler. But in this case, we also send the full traceback to the debug log.

beets/importer.py

@@ -896,8 +896,7 @@ def manipulate_files(session):
                 try:
                     item.write()
                 except library.FileOperationError as exc:
-                    log.error(u'could not write {0}: {1}'.format(
-                                  util.displayable_path(item.path), exc))
+                    log.error(exc)
 
         # Save new paths.
         with session.lib.transaction():

beets/library.py

@@ -265,28 +265,39 @@ class FileOperationError(Exception):
     Possibilities include an unsupported media type, a permissions
     error, and an unhandled Mutagen exception.
     """
-    def __init__(self, reason):
-        """Create an exception with the underlying (chained) exception
-        `reason`.
+    def __init__(self, path, reason):
+        """Create an exception describing an operation on the file at
+        `path` with the underlying (chained) exception `reason`.
         """
-        super(FileOperationError, self).__init__(reason)
+        super(FileOperationError, self).__init__(path, reason)
+        self.path = path
         self.reason = reason
 
-    def __str__(self):
-        """Get a string representing the error. Uses the same string as
-        the underlying reason.
+    def __unicode__(self):
+        """Get a string representing the error. Describes both the
+        underlying reason and the file path in question.
         """
-        return str(self.reason)
+        return u'{0}: {1}'.format(
+            util.displayable_path(self.path),
+            unicode(self.reason)
+        )
+
+    def __str__(self):
+        return unicode(self).encode('utf8')
 
 
 class ReadError(FileOperationError):
     """An error while reading a file (i.e. in `Item.read`).
     """
+    def __unicode__(self):
+        return u'error reading ' + super(ReadError, self).__unicode__()
 
 
 class WriteError(FileOperationError):
     """An error while writing a file (i.e. in `Item.write`).
     """
+    def __unicode__(self):
+        return u'error writing ' + super(WriteError, self).__unicode__()
 
 
 
@@ -384,7 +395,7 @@ class Item(LibModel):
         try:
             f = MediaFile(syspath(read_path))
         except (OSError, IOError) as exc:
-            raise ReadError(exc)
+            raise ReadError(read_path, exc)
 
         for key in ITEM_KEYS_META:
             value = getattr(f, key)
@@ -406,12 +417,12 @@ class Item(LibModel):
     def write(self):
         """Write the item's metadata to the associated file.
 
-        Can raises either a `ReadError` or a `WriteError`.
+        Can raise either a `ReadError` or a `WriteError`.
         """
         try:
             f = MediaFile(syspath(self.path))
         except (OSError, IOError) as exc:
-            raise ReadError(exc)
+            raise ReadError(self.path, exc)
 
         plugins.send('write', item=self)
 
@@ -420,7 +431,7 @@ class Item(LibModel):
         try:
             f.save(id3v23=beets.config['id3v23'].get(bool))
         except (OSError, IOError, MutagenError) as exc:
-            raise WriteError(exc)
+            raise WriteError(self.path, exc)
 
         # The file has a new mtime.
         self.mtime = self.current_mtime()

beets/ui/__init__.py

@@ -834,7 +834,7 @@ def vararg_callback(option, opt_str, value, parser):
             break
         value.append(arg)
 
-    del parser.rargs[:len(value)-1]
+    del parser.rargs[:len(value) - 1]
     setattr(parser.values, option.dest, value)
 
 
@@ -960,8 +960,15 @@ def main(args=None):
     except util.HumanReadableException as exc:
         exc.log(log)
         sys.exit(1)
+    except library.FileOperationError as exc:
+        # These errors have reasonable human-readable descriptions, but
+        # we still want to log their tracebacks for debugging.
+        log.debug(traceback.format_exc())
+        log.error(exc)
+        sys.exit(1)
     except confit.ConfigError as exc:
         log.error(u'configuration error: {0}'.format(exc))
+        sys.exit(1)
     except IOError as exc:
         if exc.errno == errno.EPIPE:
             # "Broken pipe". End silently.

beets/ui/commands.py

@@ -1137,8 +1137,7 @@ def modify_items(lib, mods, query, write, move, album, confirm):
             try:
                 item.write()
             except library.FileOperationError as exc:
-                log.error(u'could not write {0}: {1}'.format(
-                              util.displayable_path(item.path), exc))
+                log.error(exc)
 
 modify_cmd = ui.Subcommand('modify',
     help='change metadata fields', aliases=('mod',))
@@ -1238,8 +1237,7 @@ def write_items(lib, query, pretend):
             try:
                 item.write()
             except library.FileOperationError as exc:
-                log.error(u'could not write {0}: {1}'.format(
-                              util.displayable_path(item.path), exc))
+                log.error(exc)
 
 write_cmd = ui.Subcommand('write', help='write tag information to files')
 write_cmd.parser.add_option('-p', '--pretend', action='store_true',