Bug "IOError: [Errno 13] Permission denied" when editing meta-data

[ShellShock]

Calibe 1.4.

Click "Edit metadata" for an existing book.
Remove all existing formats for the book (green recycle button).
Add a new format (red plus/book button).
Click "Set metadata for the book (blue info icon)".

Error:

calibre, version 1.4.0
ERROR: Permission denied: Could not open foo.epub. Is it being used by another program?

Traceback (most recent call last):
  File "site-packages\calibre\gui2\metadata\single.py", line 341, in cover_from_format
  File "site-packages\calibre\gui2\metadata\basic_widgets.py", line 864, in get_selected_format_metadata
IOError: [Errno 13] Permission denied: u"foo.epub"

Click OK, OK to exit Edit metadata.

Click Edit metadata again. "Set metadata for the book (blue info icon)" is now OK.

[kovidgoyal]

That's almost certainly because some other program had the added file open, most likely an antivirus programor a file sync program like dropbox.

[ShellShock]

That was my first thought too, except that the problem goes away once you OK out of Edit metadata.

Here is a bit from a procmon log:

18:12:07.7208513	calibre.exe	3556	1812	CreateFile	foo.epub	ACCESS DENIED	Desired Access: Generic Read/Write, Disposition: Open, Options: Synchronous IO Non-Alert, Non-Directory File, Attributes: N, ShareMode: Read, Write, AllocationSize: n/a
18:12:14.6419783	calibre.exe	3556	1812	CreateFile	foo.epub	SUCCESS	Desired Access: Generic Read, Disposition: Open, Options: Synchronous IO Non-Alert, Non-Directory File, Attributes: N, ShareMode: Read, Write, AllocationSize: n/a, OpenResult: Opened

18:12:07: Calibre tries to open the file with read/write when I click the Info button (Set meta data for the book from the selected format), this fails as some other process already has a write lock. I OK out of Edit metadata, go back in, and then press Info button again. This now works (18:12:14) as Calibre only wants a read lock this time.

Some other process has definitely got a lock on the file. If I exit Calibre and try and open the same file from Sigil I get the same error when I save. I have not been able to work out what is locking the file--procexp is no help.

But I am a little puzzled why the Info button in Calibre Edit metadata takes a read/write lock the first time and later just a read lock? The file is external to the Calibre database, so I would expect it to only use a read lock.

Thanks for your patience.

[ShellShock]

Of course, it would help if I removed the read attribute from the epub first!

[DoctorOhh]

Originally Posted by ShellShock

Of course, it would help if I removed the read attribute from the epub first!

We've all been there at some time. Let me guess, you added the new format from a DVD or CD?

[kovidgoyal]

It uses a read write lock for legacy reasons, it does not actually write anything to the file.