heinous "cb" Dockerfile spitballing for paultag

Dockerfile

FROM tianon/frankendebian
#FROM debian:experimental

# https://wiki.debian.org/BuilddSetup
# "Configure apt (don't install recommends, no pdiffs)."
RUN { \
	echo 'APT::Install-Recommends 0;'; \
	echo 'Acquire::PDiffs "false";'; \
} > /etc/apt/apt.conf.d/buildd

RUN apt-get update && apt-get install -y build-essential && rm -rf /var/lib/apt/lists/*

# for loltesting
RUN echo 'APT::Default-Release "testing";' > /etc/apt/apt.conf.d/default

# golang (>= 2:1.2-3~),
# golang (>= 2:1.2.1-2~) | golang (<< 2:1.2.1~),
# golang (>= 2:1.3-4~) | golang (= 2:1.3-1) | golang (<< 2:1.3~),
RUN set -ex; \
	package='golang'; \
	apt-get update; \
	versions="$(apt-cache policy "$package" | awk ' \
		$1 == "Version" && $2 == "table:" { a = 1; next } \
		!/^ (   |\*\*\*) / { a = 0; next } \
		a { \
			b = substr($0, 6); \
			if (b !~ /^ /) { \
				version = substr(b, 0, index(b, " ")); \
				next \
			} \
			if (version) { \
				sub(/^ +/, "", b); \
				sep = index(b, " "); \
				priority = substr(b, 0, sep); \
				b = substr(b, sep+1); \
				sub(/^[^ ]+ /, "", b); \
				sub(/\/.*$/, "", b); \
				if (b) { \
					print priority " " version "/" b \
				} \
			} \
		} \
	' | sort --numeric-sort --stable --reverse | cut -d' ' -f2)"; \
	for version in $versions; do \
		target="${version#*/}"; \
		version="${version%/$target}"; \
		if { dpkg --compare-versions "$version" '>=' '2:1.2-3~'; } \
			&& { dpkg --compare-versions "$version" '>=' '2:1.2.1-2~' \
				|| dpkg --compare-versions "$version" '<<' '2:1.2.1~'; } \
			&& { dpkg --compare-versions "$version" '>=' '2:1.3-4~' \
				|| dpkg --compare-versions "$version" '=' '2:1.3-1' \
				|| dpkg --compare-versions "$version" '<<' '2:1.3~'; } \
		; then \
			apt-get install -t "$target" -y "$package"="$version"; \
			rm -rf /var/lib/apt/lists/*; \
			exit 0; \
		fi; \
	done; \
	exit 1