From 0beae6436784db12cddc4130d84edc24f8b9d59e Mon Sep 17 00:00:00 2001
From: Ed Morley <501702+edmorley@users.noreply.github.com>
Date: Mon, 10 Jun 2019 18:02:09 +0100
Subject: [PATCH 1/2] Prevent APT using source lists from
 /etc/apt/sources.list.d/

Previously the buildpack only passed `-o dir::etc::sourcelist` to APT,
which meant that APT still used the default `sourceparts` location of
`/etc/apt/sources.list.d/`.

This meant on cedar-14 this buildpack would use esm.ubuntu.com as an APT
source (as of heroku/stack-images/pull/140), which results in errors if
the requested packages happened to have ESM-only updates available
(since the ESM repository requires credentials since it's a paid Ubuntu
offering).

Fixes #45 / W-6224944.
---
 bin/compile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/bin/compile b/bin/compile
index c3fd679..fd8c1fd 100755
--- a/bin/compile
+++ b/bin/compile
@@ -54,7 +54,8 @@ else
 fi
 
 APT_OPTIONS="-o debug::nolocking=true -o dir::cache=$APT_CACHE_DIR -o dir::state=$APT_STATE_DIR"
-APT_OPTIONS="$APT_OPTIONS -o dir::etc::sourcelist=$APT_SOURCES"
+# Override the use of /etc/apt/sources.list (sourcelist) and /etc/apt/sources.list.d/* (sourceparts).
+APT_OPTIONS="$APT_OPTIONS -o dir::etc::sourcelist=$APT_SOURCES -o dir::etc::sourceparts=-"
 
 topic "Updating apt caches"
 apt-get $APT_OPTIONS update | indent

From 723318efb95c52f593e792f7ceacd92667e68202 Mon Sep 17 00:00:00 2001
From: Ed Morley <501702+edmorley@users.noreply.github.com>
Date: Mon, 10 Jun 2019 20:19:01 +0100
Subject: [PATCH 2/2] Use /dev/null instead

Since whilst `-` appears to work, `/dev/null` is what is referenced here:
https://salsa.debian.org/apt-team/apt/blob/f15e090301e0744471d0fbf86ea0d494f6c08215/apt-pkg/sourcelist.cc#L313
---
 bin/compile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bin/compile b/bin/compile
index fd8c1fd..037dfe0 100755
--- a/bin/compile
+++ b/bin/compile
@@ -55,7 +55,7 @@ fi
 
 APT_OPTIONS="-o debug::nolocking=true -o dir::cache=$APT_CACHE_DIR -o dir::state=$APT_STATE_DIR"
 # Override the use of /etc/apt/sources.list (sourcelist) and /etc/apt/sources.list.d/* (sourceparts).
-APT_OPTIONS="$APT_OPTIONS -o dir::etc::sourcelist=$APT_SOURCES -o dir::etc::sourceparts=-"
+APT_OPTIONS="$APT_OPTIONS -o dir::etc::sourcelist=$APT_SOURCES -o dir::etc::sourceparts=/dev/null"
 
 topic "Updating apt caches"
 apt-get $APT_OPTIONS update | indent