Merge branch 'feature/optional-dpkg-status' into 'main'

Allow apt to run if no dpkg/status file exists

See merge request apt-team/apt!257

2 files changed, 29 insertions, 8 deletions

diff --git a/apt-pkg/deb/debsystem.cc b/apt-pkg/deb/debsystem.cc
index c9c6a7e85..9c55e0a6e 100644
--- a/apt-pkg/deb/debsystem.cc
+++ b/apt-pkg/deb/debsystem.cc
@@ -335,8 +335,27 @@ 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");
+      if (dpkgstatus.empty())
+	 return true;
+      // we ignore only if the file doesn't exist, not if it is inaccessible
+      // e.g. due to permissions on parent directories as FileExists would do
+      errno = 0;
+      if (access(dpkgstatus.c_str(), R_OK) != 0 && errno == ENOENT)
+	 return true;
+      _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;
 }
diff --git a/apt-pkg/policy.cc b/apt-pkg/policy.cc
index 5fcc11b66..68b3f5e5f 100644
--- a/apt-pkg/policy.cc
+++ b/apt-pkg/policy.cc
@@ -70,17 +70,19 @@ pkgPolicy::pkgPolicy(pkgCache *Owner) : VerPins(nullptr),
    if (DefRel.empty() == false)
    {
       bool found = false;
-      // FIXME: make ExpressionMatches static to use it here easily
-      pkgVersionMatch vm("", pkgVersionMatch::None);
       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
       {
-	 if (vm.ExpressionMatches(DefRel, F.Archive()) ||
-	     vm.ExpressionMatches(DefRel, F.Codename()) ||
-	     vm.ExpressionMatches(DefRel, F.Version()) ||
+	 if (pkgVersionMatch::ExpressionMatches(DefRel, F.Archive()) ||
+	     pkgVersionMatch::ExpressionMatches(DefRel, F.Codename()) ||
+	     pkgVersionMatch::ExpressionMatches(DefRel, F.Version()) ||
 	     (DefRel.length() > 2 && DefRel[1] == '='))
 	    found = true;
       }
-      if (found == false)
+      // "now" is our internal archive name for the status file,
+      // which we should accept even if we have no status file at the moment
+      if (not found && pkgVersionMatch::ExpressionMatches(DefRel, "now"))
+	 found = true;
+      if (not found)
 	 _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
       else
 	 CreatePin(pkgVersionMatch::Release,"",DefRel,990);