make /etc/apt/preferences parser deal with comment only sections

[apt.git] / apt-pkg / policy.cc

diff --git a/apt-pkg/policy.cc b/apt-pkg/policy.cc
index 4ae3b5f8705bea5fa1f2cee782af327e16b9b106..d0f97441d878318bcb7a540324c3c8cdde6ce0fd 100644 (file)
--- a/apt-pkg/policy.cc
+++ b/apt-pkg/policy.cc
@@ -166,11 +166,15 @@ pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pk
       tracks the default when the default is taken away, and a permanent
       pin that stays at that setting.
     */
+   bool PrefSeen = false;
    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
    {
       /* Lets see if this version is the installed version */
       bool instVer = (Pkg.CurrentVer() == Ver);
 
+      if (Pref == Ver)
+        PrefSeen = true;
+
       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
       {
         /* If this is the status file, and the current version is not the
@@ -187,26 +191,33 @@ pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pk
         {
            Pref = Ver;
            Max = Prio;
+           PrefSeen = true;
         }
         if (Prio > MaxAlt)
         {
            PrefAlt = Ver;
            MaxAlt = Prio;
-        }       
-      }      
-      
+        }
+      }
+
       if (instVer == true && Max < 1000)
       {
+        /* Not having seen the Pref yet means we have a specific pin below 1000
+           on a version below the current installed one, so ignore the specific pin
+           as this would be a downgrade otherwise */
+        if (PrefSeen == false || Pref.end() == true)
+        {
+           Pref = Ver;
+           PrefSeen = true;
+        }
         /* Elevate our current selection (or the status file itself)
            to the Pseudo-status priority. */
-        if (Pref.end() == true)
-           Pref = Ver;
         Max = 1000;
-        
+
         // Fast path optimize.
         if (StatusOverride == false)
            break;
-      }            
+      }
    }
    // If we do not find our candidate, use the one with the highest pin.
    // This means that if there is a version available with pin > 0; there
@@ -394,6 +405,10 @@ bool ReadPinFile(pkgPolicy &Plcy,string File)
    PreferenceSection Tags;
    while (TF.Step(Tags) == true)
    {
+      // can happen when there are only comments in a record
+      if (Tags.Count() == 0)
+         continue;
+
       string Name = Tags.FindS("Package");
       if (Name.empty() == true)
         return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());