[arch-general] js60 update -- reveals older packages installed as deps not updated and left on system

[David C. Rankin]

All,

  I don't know if this is an old packaging problem, or if this is normal, but
with the following updates:

Packages (6) js60-60.6.3-1  linux-lts-4.19.44-1  linux-lts-headers-4.19.44-1
             perl-net-http-6.19-1  polkit-0.116-1 tmux-2.9_a-2

  I saw the:

Net Upgrade Size:       53.68 MiB

  and thought I would investigate. Checking what 'js..' packages were
installed I found:

$ pmq | grep '^js'
js 24.2.0-4
js17 17.0.0-4
js52 52.9.0-2
js60 60.6.3-1

  It was apparent that the size increase was due to the addition of js60 while
js52 remained installed. (that may or may not be expected) That prompted the
question Why are js17 and js still installed when neither are current
packages? Checking community/js185 1.0.0-8 seems to be the "current" legacy
package.

  Is this normal that new versions of packages are just added without removing
the replaced package? I would have expected 'js' to be removed when `js17` was
updated and then 'js17' to be removed when `js185` became available?

  Checking with pacman -Qi the reason `js` and `js17` were installed was as a
dependency for another package:

$ pmqi js
Name            : js
Version         : 24.2.0-4
Description     : JavaScript interpreter and libraries
<snip>
Installed Size  : 11.42 MiB
Packager        : Evangelos Foutras <evangelos at foutrelis.com>
Build Date      : Mon 07 Nov 2016 10:57:32 AM CST
Install Date    : Fri 25 Nov 2016 02:59:27 AM CST
Install Reason  : Installed as a dependency for another package
Install Script  : No
Validated By    : Signature

$ pmqi js17
Name            : js17
Version         : 17.0.0-4
Description     : JavaScript interpreter and libraries (legacy)
Architecture    : x86_64
<snip>
Conflicts With  : js<24.2.0
Replaces        : None
Installed Size  : 8.39 MiB
Packager        : Bartłomiej Piotrowski <bpiotrowski at archlinux.org>
Build Date      : Mon 07 Nov 2016 06:19:43 AM CST
Install Date    : Fri 25 Nov 2016 02:59:06 AM CST
Install Reason  : Installed as a dependency for another package
Install Script  : No
Validated By    : Signature

  Further checking whether any of the old packages are required shows they are
not, e.g.

$ pacman -Qdt
...
js 24.2.0-4
js17 17.0.0-4
js52 52.9.0-2
...

  So is this just one of those circumstances where you have to manually check
if packages are no longer needed by the system and uninstall manually? It's
not a big deal, but more a curiosity to understand when this type thing can
occur in the normal process of just calling pacman -Syu.

-- 
David C. Rankin, J.D.,P.E.