[pacman-dev] [PATCH] pacman-db-upgrade: do not mangle file lists

[Andrew Gregory]

On 10/03/14 at 08:48am, Dave Reisner wrote:
> On Thu, Oct 02, 2014 at 04:35:52PM -0400, Andrew Gregory wrote:
> > grep'ing out blank lines and sorting output thoroughly breaks any file
> > lists with %BACKUP% entries which must be separated from the file list
> > by a blank line.
> > 
> > Signed-off-by: Andrew Gregory <andrew.gregory.8 at gmail.com>
> > ---
> > 
> > Anybody who has replaced an owned directory with a symlink and run
> > pacman-db-upgrade has mangled the file list for all packages with backup files.
> > To check for broken file lists run:
> > `grep -xA1 %BACKUP% /var/lib/pacman/local/*/files | grep -B1 %FILES%`
> > Any file lists with output are broken.  Broken file lists can be repaired by
> > reinstalling the affected packages with --dbonly.  After repairing, users
> > should remove /var/lib/pacman/local/ALPM_DB_VERSION and run the fixed version
> > of pacman-db-upgrade.
> 
> Tested this since I was affected -- I don't know what the script did
> this time, but it *didn't* destroy my local DB. So, +1.
> 
> >  scripts/pacman-db-upgrade.sh.in | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/scripts/pacman-db-upgrade.sh.in b/scripts/pacman-db-upgrade.sh.in
> > index d2d317b..d7e34bd 100644
> > --- a/scripts/pacman-db-upgrade.sh.in
> > +++ b/scripts/pacman-db-upgrade.sh.in
> > @@ -211,9 +211,9 @@ if [[ -z "$db_version" ]]; then
> >  					{
> >  						if ($0 == olddir) {
> >  							# replace symlink with its target, including parents
> > -							printf("%s", parents)
> > -							printf("%s\n", newdir)
> > -						} else if ($0 == file) {
> > +							if (parents) printf("%s", parents)
> > +							if (newdir) printf("%s\n", newdir)
> 
> parents and newdir are invariants for the duration of the awk program.
> Why not skip the whole for loop when [[ -z $parents$newdir ]] ? If you
> do that, I think your printf here simply becomes:
> 
>   printf("%s%s\n", parents, newdir)
> 

We can't skip the loop because even if newdir and parents are empty
the awk script still has to remove olddir.  parents should actually
always be safe to print, so this could be reduced to:

 if(newdir) printf("%s%s\n", parents, newdir)

but I think it's easier to read treating parents and newdir
independently and similarly.

> > +						} else if (file && $0 == file) {
> >  							# newdir already existed as a file, skip it
> >  						} else if (index($0, olddir) == 1) {
> >  							# update paths that were under olddir
> > @@ -222,7 +222,7 @@ if [[ -z "$db_version" ]]; then
> >  							# print everything else as-is
> >  							print
> >  						}
> > -					}' "$f" | grep . | LC_ALL=C sort -u > "$f.tmp"
> > +					}' "$f" > "$f.tmp"
> >  				mv "$f.tmp" "$f"
> >  			done
> >  		done
> > -- 
> > 2.1.1