Check sources.list could be parsed before adding volatile files

We just used the pointer returned which might be nullptr, properly
call BuildSourceList() and check the result first.

Closes: #990518

2 files changed, 17 insertions, 0 deletions

diff --git a/apt-private/private-install.cc b/apt-private/private-install.cc
index 3ffb0be32..2420865cb 100644
--- a/apt-private/private-install.cc
+++ b/apt-private/private-install.cc
@@ -860,6 +860,8 @@ bool DoInstall(CommandLine &CmdL)
 {
    CacheFile Cache;
    Cache.InhibitActionGroups(true);
+   if (Cache.BuildSourceList() == false)
+      return false;
    auto VolatileCmdL = GetPseudoPackages(Cache.GetSourceList(), CmdL, AddVolatileBinaryFile, "");
 
    // then open the cache
diff --git a/test/integration/test-bug-990518-sourceslist-volatile b/test/integration/test-bug-990518-sourceslist-volatile
new file mode 100755
index 000000000..1353566a3
--- /dev/null
+++ b/test/integration/test-bug-990518-sourceslist-volatile
@@ -0,0 +1,15 @@
+#!/bin/sh
+set -e
+
+TESTDIR="$(readlink -f "$(dirname "$0")")"
+. "$TESTDIR/framework"
+
+setupenvironment
+configarchitecture 'amd64'
+
+buildsimplenativepackage 'foo' 'amd64' '1'
+
+echo foo > rootdir/etc/apt/sources.list.d/test.list
+
+testfailureequal "E: Malformed line 1 in source list ${TMPWORKINGDIRECTORY}/rootdir/etc/apt/sources.list.d/test.list (type)
+E: The list of sources could not be read." apt install ./incoming/foo_1_amd64.deb -s