Re: [Gnu-arch-users] [BUG] can get duplicate explicit IDs if adding fast enough

[Aaron Bentley]

Colin Walters wrote:
> Hi,
>
> A better explicit ID algorithm is needed.  Currently if you add files
> fast enough, it's possible to get two files with the same ID, since the
> current algorithm just uses the time, basically.
>
> Maybe we could switch to just original file path and SHA1 sum?

That just changes the conditions under which you get duplicate IDs to

$ touch foo
$ tla add-id foo
$ tla mv foo bar
$ touch foo
$ tla add-id foo

(two empty files would have the same SHA1 sum)

Also, files don't necessarily exist when added.  (treat as empty? worse!)
Also, SHA1 support hasn't been merged yet.

There's a very simple way to get a guaranteed unique ID; use a sequence 
number.  This would require an extra file (with locking protocol), or 
else a tree-inventory for every add.

Aaron
--
Aaron Bentley
Director of Technology
Panometrics, Inc.