When doc-base triggers were run between perl 5.20 unpack and configuration
there was the following error:

Распаковывается perl-base (5.20.0-4) на замену
(5.18.2-7) …
Обрабатываются триггеры для man-db (2.6.7.1-1) …
Обрабатываются триггеры для doc-base (0.10.5) …
Possible precedence issue with control flow operator at
/usr/share/perl5/Debian/DocBase/DB.pm line 101.
The following error has occured while loading doc-base modules:

Can't locate UUID.pm in @INC (you may need to install the UUID module) (@INC
contains: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.20.0
/usr/local/share/perl/5.20.0 /usr/lib/x86_64-linux-gnu/perl5/5.20
/usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.20 /usr/share/perl/5.20
/usr/local/lib/site_perl .) at
/usr/share/perl5/Debian/DocBase/Programs/Scrollkeeper.pm line 21.
BEGIN failed--compilation aborted at
/usr/share/perl5/Debian/DocBase/Programs/Scrollkeeper.pm line 21.
Compilation failed in require at /usr/share/perl5/Debian/DocBase/InstallDocs.pm
line 25.
BEGIN failed--compilation aborted at
/usr/share/perl5/Debian/DocBase/InstallDocs.pm line 25.
Compilation failed in require at /usr/sbin/install-docs line 27.

*******************************************************************
It seems install-docs is not fully functional at the moment,
and it will try to recover from the error next time it is called.

Please run `install-docs --install-changed' command
manually after the upgrade process is finished.
*******************************************************************

Настраивается пакет perl-base (5.20.0-4) …



Running install-docs --install-changed manually after that was OK.

I suspect errors I got are related:

Processing triggers for doc-base (0.10.5) ...
Possible precedence issue with control flow operator at /usr/share/perl5/Debian/DocBase/DB.pm line 101.
Database error: Cannot read file `/var/lib/doc-base/info/status.yml': Can't locate PerlIO.pm in @INC (you may need to install the PerlIO module) (@INC contains: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.20.0 /usr/local/share/perl/5.20.0 /usr/lib/x86_64-linux-gnu/perl5/5.20 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.20 /usr/share/perl/5.20 /usr/local/lib/site_perl .) at /usr/share/perl5/YAML/Tiny.pm line 187.
BEGIN failed--compilation aborted.
.

**  Trying to recover from the above install-docs error by
**  removing its internal databases and re-calling it afterwards

Possible precedence issue with control flow operator at /usr/share/perl5/Debian/DocBase/DB.pm line 101.
Registering 203 doc-base files...
Error in `/usr/share/doc-base/libxml-parser-perl', line 10: all `Format' sections are invalid.
Database error: Cannot save file `/var/lib/doc-base/info/status-new.yml': Can't locate PerlIO.pm in @INC (you may need to install the PerlIO module) (@INC contains: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.20.0 /usr/local/share/perl/5.20.0 /usr/lib/x86_64-linux-gnu/perl5/5.20 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.20 /usr/share/perl/5.20 /usr/local/lib/site_perl .) at /usr/share/perl5/YAML/Tiny.pm line 582.
BEGIN failed--compilation aborted.
.
dpkg: error processing package doc-base (--unpack):
 subprocess installed post-installation script returned error exit status 10
Errors were encountered while processing:
 doc-base


Not quite sure what happened, as libyaml-tiny-perl depends on perl,
which depends on perl-modules, which provides PerlIO. Must have
something to do with the versions...