■ Leftovers and leaves 
Since I covered my use case for pkg_comp already, today I wanted to
address another question, which is 'how to keep things tidy'.

By default, pkgsrc wil store locally built binaries in the PACKAGES
directory, which usually corresponds to $PKGSRCDIR/packages/All.
Previously fetched distfiles are kept for later use in inside DISTDIR
($PKGSRCDIR/distfiles) instead, unless  `make distclean' is executed in
the package directory.

As new releases come and go, both PACKAGES and DISTDIR will begin to
be populated with multiple versions of the same files, most of which are
left there collecting dust. 

All these old/orphaned/unused files tend to occupy a non-negligible
amount of space over the time, and make it harder to skim through the
repo and the distfiles directories, in search of whatever I may need. 

The problem becomes all the more relevant on trunk, where the turnover
of new package versions is kept constantly high.

My former solution consisted in a bunch of half-baked scripts which
searched for multiple versions of the same files (dropping older ones) and
for leftovers of uninstalled software.

And it worked, with the limitations imposed by my limited skills. More
recently however, as I began sharing my pkgsrc packages for Slackware,
I felt the need of a proper solution, capable of keeping my repo devoid of
cluttern.

I discovered and utility, which somehow I had managed to miss for all
this time, thanks to a post on an Italian tech blog covering the setup
of pkgsrc on Slackware. [1]

I'm referring to pkgtools/lintpkgsrc [2], which turned out to be the 
no.1 swiss army knive of pkgsrc repo maintenance.  

[1] <https://wiki.golem.linux.it/Pkgsrc_su_Slackware>
[2] <https://pkgsrc.se/pkgtools/lintpkgsrc>

> DESCRIPTION
> lintpkgsrc tries to verify the entire contents of the pkgsrc tree.
> lintpkgsrc uses simple regular-expression matching for verifying
> files that make up a pkgsrc directory.  Note that it does NOT
> implement a complete Makefile parser.

I recommend reading the manpage carefully. The package provides quite a
handful of cool functions to manage a pkgsrc repo (and also get you out
of trouble), but they have to be used wisely.

As a starter `-i' checks the version of each installed package against
the current version in pkgsrc.

■ Remove outdated <leaf> packages
According to the manual, lintpkgsrc(1) supports a `-r' switch
which most closely resembled what I was looking for.

  -r	Remove distfiles which are not referenced from any
> package's distinfo file, or have an incorrect checksum
> (usually due to an interrupted download), and any old
> binary packages.  To remove any given type, additionally
> specify the -o, -m, or -p flags respectively.

Now, my only problem with that is 'and any old binary packages':

Supposing in fact that I finally managed to compile and install Firefox
(hereafter referred to as 'Nightly') version 1562, after hours and hours
of waiting and a substantial electricity consumption, and then Nightly
1563 comes out, lintpkgsrc deletes my previous package, a bug is found
in 1563 and I'm unable to roll-back? 

And what if I wanted to keep 1562 and skip few versions in order to save
time, while still being able to install/uninstall the package at will?

To address this issue I wrote the small script you can see below.  It
asks lintpkgsrc to look for outdated binaries in the repo, using with
the `-p' option. A file list containing deprecated packages is hereby
generated and confronted with the package database: binaries of 
installed packages are retained even if outdated, while all the other
are discarded. In other words, only orphaned 'leaf' binaries are purged.

```

#!/bin/sh

PREFIX=/usr/pkg
LINTDIR=${PKGSRCDIR}/lint
PKGDBDIR=${PREFIX}/pkgdb
PACKAGES=${PKGSRCDIR}/packages

set -e

# directory checks
if [ ! -d "${PKGSRCDIR}" ]; then
    	echo "PKGSRCDIR not set"
	exit 1
else
	[ -d ${LINTDIR} ] || \
	( echo 'creating lint dir' && mkdir ${LINTDIR} )
fi

# clean up previous logs
for f in pkgs old leafs
      	do [ -f	"${f}" ] && rm ${LINTDIR}/${f}
done

# scan for outdated binaries
printf "Looking for obsolete packages...\n"
lintpkgsrc -K $PACKAGES -p \
	| grep -v 'Cannot extract\|Bogus' \
	| sed -n -e 's/^.*All\///p' \
	> ${LINTDIR}/pkgs

# prune leaf binaries and orphaned sources
printf "Creating file lists...\n"
cat ${LINTDIR}/pkgs | while read p; do
	pbase=`basename $p .tgz`
	if [ -d ${PKGDBDIR}/${pbase} ]; then
  		echo "$p" >> ${LINTDIR}/old
	else
		echo "$p" >> ${LINTDIR}/leafs
	fi
done

printf "Pruning leaf binaries...\n"
cat ${LINTDIR}/leafs | 
while read in; do
	rm -f ${PACKAGES}/"$in"
done

```

■ Prune deprecated distfiles 
A little word on outdated distfiles; they can be easily pruned  
with:

$ export PACKAGES=/path/to/packages
$ lintpkgsrc -or

Notice the additional `-o' option before -r, which reports old distfiles
only. `-m' can be added as a further sanity check.  

> -m For each current distfile, verify its checksum against
> the appropriate pack‐ age's distinfo file.  Also report if
> any package's distinfo file references the same distfile
> with a different distinfo checksum.

A comparable functionality (not covering `-m') is provided
also by pkgtools/pkg_distinst, which is a perl script.