human-readable errors in read() and write()

beets/library.py

@@ -320,11 +320,9 @@ class Item(object):
             read_path = normpath(read_path)
         try:
             f = MediaFile(syspath(read_path))
-        except Exception:
-            log.debug(u'failed reading file: {0}'.format(
-                displayable_path(read_path))
-            )
-            raise
+        except (OSError, IOError) as exc:
+            raise util.FilesystemError(exc, 'read', (self.path,),
+                                       traceback.format_exc())
 
         for key in ITEM_KEYS_META:
             setattr(self, key, getattr(f, key))
@@ -340,7 +338,12 @@ class Item(object):
         """
         plugins.send('write', item=self)
 
-        f = MediaFile(syspath(self.path))
+        try:
+            f = MediaFile(syspath(self.path))
+        except (OSError, IOError) as exc:
+            raise util.FilesystemError(exc, 'read', (self.path,),
+                                       traceback.format_exc())
+
         for key in ITEM_KEYS_WRITABLE:
             setattr(f, key, getattr(self, key))
 

beets/mediafile.py

@@ -59,6 +59,10 @@ log = logging.getLogger('beets')
 class UnreadableFileError(IOError):
     pass
 
+class FileIOError(UnreadableFileError, IOError):
+    def __init__(self, exc):
+        IOError.__init__(self, exc.errno, exc.strerror, exc.filename)
+
 # Raised for files that don't seem to have a type MediaFile supports.
 class FileTypeError(UnreadableFileError):
     pass
@@ -864,8 +868,8 @@ class MediaFile(object):
         except unreadable_exc as exc:
             log.debug(u'header parsing failed: {0}'.format(unicode(exc)))
             raise UnreadableFileError('Mutagen could not read file')
-        except IOError:
-            raise UnreadableFileError('could not read file')
+        except IOError as exc:
+            raise FileIOError(exc)
         except Exception as exc:
             # Hide bugs in Mutagen.
             log.debug(traceback.format_exc())

beets/util/__init__.py

@@ -97,7 +97,7 @@ class FilesystemError(HumanReadableException):
             clause = 'while {0} {1} to {2}'.format(
                 self._gerund(), repr(self.paths[0]), repr(self.paths[1])
             )
-        elif self.verb in ('delete', 'write', 'create'):
+        elif self.verb in ('delete', 'write', 'create', 'read'):
             clause = 'while {0} {1}'.format(
                 self._gerund(), repr(self.paths[0])
             )

docs/changelog.rst

@@ -31,6 +31,8 @@ Changelog
 * The :ref:`fields-cmd` command shows template fields provided by plugins.
   Thanks again to Pedro Silva.
 * Album art filenames now respect the :ref:`replace` configuration.
+* Friendly error messages are now printed when trying to read or write files
+  that go missing.
 
 1.1.0 (April 29, 203)
 ---------------------