re: toolchain/52804: make postinstall obsoletelibs a separate thing?

[matthew green <mrg%eterna.com.au@localhost>]

>  On Sun, Dec 10, 2017 at 05:15:01AM +0000, David Holland wrote:
>  > It occurred to me tonight while working on unborking a machine that
>  > was running a mixture of 6.1 and 7.99.33 that it would be useful to be
>  > able to run subsets of "postinstall fix obsolete", so as to allow
>  > clearing away the bulk of the obsolete files while leaving dangerous
>  > ones or suspect ones for closer analysis.
>  > 
>  > But I think it would be sufficient to just split the obsolete library
>  > handling apart from the obsolete paths handling and make them separate
>  > toplevel targets. As far as I know the downgrade hazards associated
>  > with postinstall fix obsolete are limited to shared library images.
>  
>  Can you please expand what you want in more detail?
>  AFAIK, postinstall fix does not delete old versions of libraries.
>   Thomas

the main problem is that it can delete the version pointed to
by the symlinks.  it deletes all but the latest of a major
version of a library, but if you downgrade, then the latest
is no longer the "in use" one, but postinstall deletes it.

eg, say you have libfoo.so.2.3, ugprade to libfoo.so.2.4 and
then find a bug, and install old libs.  libfoo.so and
libfoo.so.2 now point to libfoo.so.2.3 but install will
delete this version, since it's older than libfoo.so.2.4.

it's really annoying, and i'd rather fix this than to make
the change dh is suggesting, but either would be good..


.mrg.