Hi Felix,

thanks for the feedback.

As for diff:
No, diff as suggested in the REP runs diff on all SCM (git, svn, 
mercurial) controlled directories and gives you the results. So it shows 
what files you have modified in all SCM controlled directories mentioned 
in your .rosinstall.

What you suggest is something like what aptitude does, asking the user 
for confirmation before executing any change. This would be possible 
with rosinstall as well, such as a message:
----------------------------
Rosinstall will perform the following changes:
- modify .rosinstall
- modify setup.sh
- svn update foo
- git fetch bar
Do you want to continue? [Y/n/?]
----------------------------

Or even display a diff on the setup files to change. And aptitude has a 
switch "-y Assume that the answer to simple yes/no questions is 'yes'"

There is no such feature in rosinstall today (and was not planned in the 
REP, yet).
There are tickets #3492 and #3521 waiting for Tully to comment on, which 
would already make rosinstall explain more.


rosinstall currently can change any of the directories it knows under 
version control (by running e.g. svn update), as well as the .rosinstall 
and setup.* files. One thing you can do is to put your .rosinstall and 
setup.* files into a lightweight version control like git that way 
creating backups and going back on these files becomes easy.
Though for that, you'd need to know such an SCM well enough and be happy 
to use it for that purpose.

regards,
   Thibault

On 07/21/2011 01:46 PM, Felix Kolbe wrote:
> Hello Thibault et al.,
>
> I appreciate your working on rosinstall. It isn't that easy to
> understand. And I really hate running it for an update because I get
> absolutely no idea what had been changed and therefore will help or
> disturb my development. If that's what your --diff is to be meant for,
> that would be great! (Let me know if I missed the
> view-detailed-changes-before-updating feature somewhere.)
>
> Best Regards,
> Felix