Re: Make etcupdate bootstrap requirement due to previous mergemaster usage more clear in handbook

On Fri, 03 Dec 2021 05:54:37 -0800 (PST)
"Jeffrey Bouquet" <jbtakk@iherebuywisely.com> wrote:

> 
> 
> On Fri, 3 Dec 2021 13:58:39 +0100, Miroslav Lachman <000.fbsd@quip.cz> wrote:
> 
> > On 03/12/2021 12:52, Yetoo Happy wrote:
> > 
> > [...]
> > 
> > >  Quick Start* and follow the instructions and get to step
> > > 7 and may think that even though etcupdate is different from mergemaster
> > > from the last time they used the handbook they have faith that following
> > > the instructions won't brick their system. This user will instead find that
> > > faith in general is just a very complex facade for the pain and suffering
> > > of not following *24.5.6.1 Merging Configuration Files* because the user
> > > doesn't know that step exists or relevant to the current step and ends up
> > > unknowingly having etcupdate append "<<<< yours ... >>>>> new" to the top
> > > of the user's very important configuration files that they didn't expect
> > > the program to actually modify that way when they resolved differences nor
> > > could they predict easily because the diff format is so unintuitive and
> > > different from mergemaster. Now unable to login or boot into single user
> > > mode because redirections instead of the actual configuration is parsed the
> > > user goes to the handbook to find out what might have happened and scrolls
> > > down to find *24.5.6.1 Merging Configuration Files* is under *24.5.6.
> > 
> > [...]
> > 
> > That's why I think etcupdate is not so intuitive as tool like this 
> > should be and etcupdate is extremely dangerous because it intentionally 
> > breaks syntax of files vital to have system up and running.
> > If anything goes wrong with mergemaster automatic process then your have 
> > configuration not updated which is almost always fine to boot the system 
> > and fix it. But after etcupdate? Much worse...
> > 
> > I maintain about 30 machines for 2 decades and had problems with 
> > etcupdate many times. I had ti use mergemaster as fall back many times. 
> > Mainly because of etcupdate said "Reference tree to diff against 
> > unavailable" or "No previous tree to compare against, a sane comparison 
> > is not possible.". And sometimes because etcupdate cannot automatically 
> > update many files in /etc/rc.d and manual merging of a lot of files with 
> > "<<<< ==== >>>>" is realy painful while with mergemaster only simple 
> > keyboard shortcuts will solve it.
> > All of this must be very stressful for beginners.
> > 
> > So beside the update of documentation I really would like to see some 
> > changes to etcupdate workflow where files are modified in temporary 
> > location and moved to destination only if they do not contain any syntax 
> > breaking changes like <<<<, ====, >>>>.
> > 
> > Kind regards
> > Miroslav Lachman
> 
> 
> Agree. I fell back to mergemaster this Nov on 13-stable when the /var files
> pertaining to etcupdate were all missing current /etc data, and no study of
> man etcupdate was clear enough to rectify such a scenario, and suspect my
> initial use of etcupdate will or may require a planned reinstall,  not having
> had to do so since Jan 2004 iirc,  [ vs failed hard disk migrations ] and 
> I am just hoping mergemaster stays in /usr/src and updated 
> for system changes, even if moved to 'tools' or
> something, since its use seems intuitive and much less of a black box. 
> Also, /usr/src/UPDATING still at the bottom emphasizes mergemaster still. 
> 

Not sure it's fixed or not (tooo dangerous to try...), -n (dry-run)
option of etcupdate is now quite harmful. Maybe by any commit done in
this april on main (MFC'ed to stable/13 in june).

 *I got busy manually checking and applying changes to /etc, and
  forgot to file PR.

Doing `etcupdate -n` itself runs OK, but following `etcupdate -B` does
NOT do anything, hence nothing is actually updated.
The only workaround I have is NOT to try dry-run.

It would be because the same trees are used for dry-run and actual run.
(Not looked into the code. Just a thought.)

Maybe using dedicated trees (older one is copied from actual current
one, building current tree on dedicated place and delete them every
time the dry-run finishes) for dry-run would fix.

And copying /etc to some temporary place and applying changes to it,
copy back to /etc may be help for your issue, I think.

-- 
Tomoaki AOKI    <junchoon@dec.sakura.ne.jp>