Since I’ve started using vim with elixir-ls language server, I’ve noticed that Archlinux erlang package is built without docs, so I couldn’t use my LSP-completer in full power. That prompted me to investigate the Arch Build System, a ports-like system for building and packaging software from source code.

Here’s how I managed to compile Erlang with docs using ABS.

Install asp tool

$ sudo pacman -S asp

asp is a bash script that aids in the management of ABS package sources.

Setup

$ mkdir ~/src/abs
$ cd ~/src/abs
$ asp export erlang
$ cd erlang

asp export will get latest version of the package from repo into directory with the same name.

Make changes in PKGBUILD file

diff --unified
--- /path/to/old/PKGBUILD      2023-01-03 18:04:48.769418824 +0200
+++ PKGBUILD    2023-01-03 17:58:57.291392260 +0200
@@ -16,6 +16,7 @@
 license=(Apache)
 makedepends=(fop git glu java-environment libxslt lksctp-tools mesa perl unixodbc wxwidgets-gtk3)
 options=(staticlibs)
+groups=(modified)
 source=(epmd.conf
         epmd.service
         epmd.socket
@@ -44,6 +45,7 @@
     --prefix=/usr \
     --with-odbc
   make
+  make docs DOC_TARGETS=chunks
 }

 package_erlang() {
@@ -57,6 +59,7 @@

   export PATH="$srcdir/bin:$PATH"
   make -C otp DESTDIR="$pkgdir" install
+  make -C otp DESTDIR="$pkgdir" DOC_TARGETS=chunks install-docs

   # move files that belong to the erlang-unixodbc package
   mkdir -p unixodbc

By making those changes, we add the generated package to the ‘modified’ group (you’ll see later why) while also instructing makepkg to build and install Erlang documentation.

Next, run:

$ makepkg -si

-si flags ensure that makepkg retrieves needed dependencies and auto-installs the package after compilation.

Add this line into /etc/pacman.conf

IgnoreGroup = modified

That’s why I’ve added the package to the ‘modified’ group:

If new versions are available in the official repositories during a system update, pacman prints a note that it is skipping this update because it is in the IgnoreGroup section. At this point, the modified package should be rebuilt from ABS to avoid partial upgrades.