Will apt-get upgrade modify symlinks? For example libphp7 symlinked instead of libphp5 under /etc/alternatives

Question

I performed sudo apt-get upgrade. $ sudo apt-get upgrade

After the upgrade, I noticed some php 5.7 files and folders in the etc directory For example: I saw /usr/bin/php7.1 and /etc/php/7.0, 7.1, 7.2, 7.3

I'm not sure why 7.1 files are installed as I didn't intend to do that and the php app doesn't work with PHP7.

I'm not sure after the upgrade if /etc/alternatives/php got symlinked to /usr/bin/php7.1 how do I confirm if upgrade modifies symlinks?

So, I performed to be sure 5.6 modules/extensions is loading and not 5.7
$ sudo update-alternatives --set php /usr/bin/php5.6

I then checked the symlinks: I checked for symlinks

ubuntu@ip:/etc/alternatives$ ls -alth | grep php lrwxrwxrwx 1 root root 15 Aug 27 14:05 php -> /usr/bin/php5.6 lrwxrwxrwx 1 root root 31 Aug 27 14:05 php.1.gz -> /usr/share/man/man1/php5.6.1.gz lrwxrwxrwx 1 root root 16 Aug 25 02:21 phpize -> /usr/bin/phpize5 lrwxrwxrwx 1 root root 32 Aug 25 02:21 phpize.1.gz -> /usr/share/man/man1/phpize5.1.gz lrwxrwxrwx 1 root root 20 Aug 25 02:21 php-config -> /usr/bin/php-config5 lrwxrwxrwx 1 root root 36 Aug 25 02:21 php-config.1.gz -> /usr/share/man/man1/php-config5.1.gz lrwxrwxrwx 1 root root 21 Mar 16 2017 libphp7 -> /usr/lib/libphp7.1.so 

and found libphp7 is symlinked to 7.1. Should it matter? We don't want 7.1 modules or extensions to load as we are on php5.6 but will symlink libphp7.1 create any problems in the future? if so how to fix this and get back 5.6.37?

Thanks!

Answer 1

As far as I can tell from the package index the latest officially supported package from Ubuntu for 14.04 is php 5.5.9 (https://packages.ubuntu.com/trusty-updates/php5).

Given that you mention both php5.6 and php7.1 it is clear that you are almost certainly running a package from some unofficial repository.

Anyway, to answer your question, yes, installing or upgrading a package can update symlinks and modify the 'alternatives'. Official packages almost never do this unless your system would be left in a broken state if they didn't get updated.

Unofficial packages may not fully be following the development standards and might switch your defaults unexpectedly. If you are going to use unofficial packages, my suggestion is either you monitor any changelogs or mailling lists for that unofficial source. Also, you should probably be testing any upgrades in a development environment so if/when things change you can repair it without any production impact.