Description:
Encountered when attempting to build and install https://aur.archlinux.org/packages/maperitive-bin/ with "makepkg -i"

$ makepkg -i
(...)
==> Creating package "maperitive-bin"...
-> Generating .PKGINFO file...
-> Adding install file...
-> Generating .MTREE file...
-> Compressing package...
==> Leaving fakeroot environment.
==> Finished making: maperitive-bin :20140503-1 (Sat 28 Jun 15:16:53 BST 2014)
==> Installing package maperitive-bin with pacman -U...
/usr/bin/makepkg: line 849: ((: ! : syntax error: operand expected (error token is "! ")
loading packages...
error: '/home/cina/build/PACKAGES/maperitive-bin-:20140503-1-x86_64.pkg.tar.xz': could not find or read package
==> WARNING: Failed to install built package(s).

When followed by another "makepkg -i", the package gets installed without errors.

_______________________________________________________________________________________________________________

It seems that the sufficient conditions to trigger this are:
in a PKGBUILD

epoch=''
AND
pkgver='some value'
AND
pkgver() {
output different from "$pkgver"
}



Additional info:
* pacman 4.1.2-6


Steps to reproduce:

Build and install maperitive-bin with "makepkg -i"

Alternatively, since maperitive-bin pulls mono, steps to reproduce are:

$ mkdir fakepkg
$ cd fakepkg
$ touch fakefile

Save the following as PKGBUILD:
##############################################
# Maintainer: Your Name <youremail@domain.com>
pkgname=fakepkg
pkgver=1
pkgrel=1
epoch=
pkgdesc="fake description"
arch=('any')
url=""
license=('GPL')
groups=()
depends=()
makedepends=()
checkdepends=()
optdepends=()
provides=()
conflicts=()
replaces=()
backup=()
options=()
install=
changelog=
source=('fakefile')
noextract=()
md5sums=('SKIP')

pkgver() {
echo "2"
}

package() {
install -Dm644 "$srcdir/fakefile" "$pkgdir/usr/share/fakepkg/fakefile"
}

##############################################
$ makepkg -i
$ makepkg -i # Again

$ pacman -R fakepkg