[Audacity-devel] Another dataloss bug

[Matt B. <mbr...@cs...>]

Zenkov Mihail found a way to reproduce another dataloss bug.  This
bug affects both 1.2.0 and 1.2.1.

The problem appears to be with AUP file loading creating multiple
BlockFiles sharing the same filename.  Here's what happens.  The
problem starts at step 3b:

 1. Save a project file with two duplicate tracks, each referencing
    the same BlockFile (I'll call it "b1.aup").

 2. Close the project.

 3. Re-open the project file:

    a. When the first track is loaded from the XML file, it creates
       a BlockFile with filename "b1.aup".

    b. When the second track is loaded from the XML file, it creates
       another BlockFile with filename "b1.aup".

 4. Delete the second track.

 5. Save and close the project:

    a. The first track's BlockFile is locked and then derefed.

    b. The second track's BlockFile is dereferenced but NOT locked
       (because it is no longer in the saved version), so "b1.aup"
       is deleted.

In Audacity 1.0, a hash was used to ensure that only one BlockFile was
created for each filename.  However, it looks like the relevant code
(in DirManager::LoadBlockFile) is no longer called since we switched to
the new XML file format.

I haven't started working on a fix for this.


Here are the steps to reproduce the bug:

---------- Forwarded message ----------
From: Zenkov Mihail <kr...@tu...>
To: aud...@li...
Date: Mon, 10 May 2004 04:42:46 +0300
Subject: [Audacity-users] bad bug

I reduce steps to reproduce this bug:
1. open audacity
2. import audio (i use mono wav  float/48khz 3.05min)
3. effect->normalize
4. duplicate
5. save project as
6. close audacity
7. open audacity
8. open project
9. click in the middle of second track
10. select from middle to the end in second track
11. delete
12. save project
13. close audacity
14. open audacity
15. open project