309562 - nsLocalFile::CopySingleFile backup names need unique-ifying

Status: NEW

(Core :: XPCOM, defect)

Description

[Dan Mosedale (:dmosedale, :dmose)]

I just killed a bunch of hours tracking down a bug to code with the following 
comment (see the URL field):

// remove any existing backup file that we may already have.
// maybe we should be doing some kind of unique naming here,
// but why bother.

The answer to this (obviously rhetorical) question is this: if code calls 
nsILocalFile::MoveTo() twice in (not particularly rapid) succession to rotate 
backup files, then somebody (the kernel?) can still be holding on to the first 
backup when the second backup attempt tries to remove it.  This means that the 
remove (and therefore the subsequent MoveFile) fails, causing the entire MoveTo 
to croak with the extremely unhelpful NS_ERROR_FAILURE.

Comment 1

[Doug Turner (:dougt)]

mass reassigning to nobody.