Report failures back from debSystem::AddStatusFiles

Failing to properly create the status file class should be reported back
to the caller so it can proceed accordingly instead of proceeding into
more failures.

This gives us:
E: flAbsPath on /var/lib/dpkg/status failed - realpath (2: No such file or directory)
E: The package lists or status file could not be parsed or opened.
instead of:
E: flAbsPath on /var/lib/dpkg/status failed - realpath (2: No such file or directory)
E: Could not open file  - open (2: No such file or directory)
E: Problem opening
E: The package lists or status file could not be parsed or opened.
and valgrind reporting actions on uninitialised values.

1 files changed, 14 insertions, 2 deletions

diff --git a/apt-pkg/deb/debsystem.cc b/apt-pkg/deb/debsystem.cc
index c9c6a7e85..65a27f72f 100644
--- a/apt-pkg/deb/debsystem.cc
+++ b/apt-pkg/deb/debsystem.cc
@@ -335,8 +335,20 @@ signed debSystem::Score(Configuration const &Cnf)
 /* */
 bool debSystem::AddStatusFiles(std::vector<pkgIndexFile *> &List)
 {
-   if (d->StatusFile == 0)
-      d->StatusFile = new debStatusIndex(_config->FindFile("Dir::State::status"));
+   if (d->StatusFile == nullptr)
+   {
+      auto dpkgstatus = _config->FindFile("Dir::State::status");
+      _error->PushToStack();
+      d->StatusFile = new debStatusIndex(std::move(dpkgstatus));
+      bool const errored = _error->PendingError();
+      _error->MergeWithStack();
+      if (errored)
+      {
+	 delete d->StatusFile;
+	 d->StatusFile = nullptr;
+	 return false;
+      }
+   }
    List.push_back(d->StatusFile);
    return true;
 }