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

On Wed, 8 Dec 2021 09:11:05 -0800
John Baldwin <jhb@FreeBSD.org> wrote:

> On 12/3/21 6:09 PM, Tomoaki AOKI wrote:
> > 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.
> 
> Humm.
> 
> > It would be because the same trees are used for dry-run and actual run.
> > (Not looked into the code. Just a thought.)
> 
> So the new changes always build a temporary tree (vs trying to build
> /var/db/etupdate/current in place).  For -n it should be that it just
> doesn't change /var/db/etcupdate/current at the end, but if it did the
> move anyway that would explain the bug you are seeing.  That does indeed
> look broken.  Please file a PR as a reminder for me to fix it.
> 
> -- 
> John Baldwin
> 

Done.

 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=260281

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