]> git.saurik.com Git - apt.git/blobdiff - apt-pkg/packagemanager.cc
Bug #807012 also involves package dependencies :/.
[apt.git] / apt-pkg / packagemanager.cc
index a2079a2e4554d76429a8765612cb2c690eae4dae..90dd3a3ee29e078c390af424fab0c137d7880c70 100644 (file)
@@ -6,25 +6,34 @@
    Package Manager - Abstacts the package manager
 
    More work is needed in the area of transitioning provides, ie exim
-   replacing smail. This can cause interesing side effects.
+   replacing smail. This can cause interesting side effects.
 
    Other cases involving conflicts+replaces should be tested. 
    
    ##################################################################### */
                                                                        /*}}}*/
 // Include Files                                                       /*{{{*/
-#include<config.h>
+#include <config.h>
 
 #include <apt-pkg/packagemanager.h>
 #include <apt-pkg/orderlist.h>
 #include <apt-pkg/depcache.h>
 #include <apt-pkg/error.h>
+#include <apt-pkg/edsp.h>
 #include <apt-pkg/version.h>
 #include <apt-pkg/acquire-item.h>
 #include <apt-pkg/algorithms.h>
 #include <apt-pkg/configuration.h>
-#include <apt-pkg/sptr.h>
-
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/cacheiterators.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/install-progress.h>
+#include <apt-pkg/prettyprinters.h>
+
+#include <stddef.h>
+#include <list>
+#include <string>
 #include <iostream>
 
 #include <apti18n.h>
@@ -37,7 +46,7 @@ bool pkgPackageManager::SigINTStop = false;
 // ---------------------------------------------------------------------
 /* */
 pkgPackageManager::pkgPackageManager(pkgDepCache *pCache) : Cache(*pCache),
-                                                           List(NULL), Res(Incomplete)
+                                                           List(NULL), Res(Incomplete), d(NULL)
 {
    FileNames = new string[Cache.Head().PackageCount];
    Debug = _config->FindB("Debug::pkgPackageManager",false);
@@ -129,7 +138,7 @@ bool pkgPackageManager::FixMissing()
 // PM::ImmediateAdd - Add the immediate flag recursivly                        /*{{{*/
 // ---------------------------------------------------------------------
 /* This adds the immediate flag to the pkg and recursively to the
-   dependendies 
+   dependencies
  */
 void pkgPackageManager::ImmediateAdd(PkgIterator I, bool UseInstallVer, unsigned const int &Depth)
 {
@@ -152,7 +161,7 @@ void pkgPackageManager::ImmediateAdd(PkgIterator I, bool UseInstallVer, unsigned
         if(!List->IsFlag(D.TargetPkg(), pkgOrderList::Immediate))
         {
            if(Debug)
-              clog << OutputInDepth(Depth) << "ImmediateAdd(): Adding Immediate flag to " << D.TargetPkg() << " cause of " << D.DepType() << " " << I.FullName() << endl;
+              clog << OutputInDepth(Depth) << "ImmediateAdd(): Adding Immediate flag to " << APT::PrettyPkg(&Cache, D.TargetPkg()) << " cause of " << D.DepType() << " " << I.FullName() << endl;
            List->Flag(D.TargetPkg(),pkgOrderList::Immediate);
            ImmediateAdd(D.TargetPkg(), UseInstallVer, Depth + 1);
         }
@@ -182,7 +191,7 @@ bool pkgPackageManager::CreateOrderList()
       if (I->VersionList == 0)
         continue;
       
-      // Mark the package and its dependends for immediate configuration
+      // Mark the package and its dependents for immediate configuration
       if ((((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential) &&
          NoImmConfigure == false) || ImmConfigureAll)
       {
@@ -215,7 +224,7 @@ bool pkgPackageManager::CreateOrderList()
    return true;
 }
                                                                        /*}}}*/
-// PM::DepAlwaysTrue - Returns true if this dep is irrelevent          /*{{{*/
+// PM::DepAlwaysTrue - Returns true if this dep is irrelevant          /*{{{*/
 // ---------------------------------------------------------------------
 /* The restriction on provides is to eliminate the case when provides
    are transitioning between valid states [ie exim to smail] */
@@ -243,24 +252,51 @@ bool pkgPackageManager::CheckRConflicts(PkgIterator Pkg,DepIterator D,
          D->Type != pkgCache::Dep::Obsoletes)
         continue;
 
-      // The package hasnt been changed
+      // The package hasn't been changed
       if (List->IsNow(Pkg) == false)
         continue;
       
-      // Ignore self conflicts, ignore conflicts from irrelevent versions
+      // Ignore self conflicts, ignore conflicts from irrelevant versions
       if (D.IsIgnorable(Pkg) || D.ParentVer() != D.ParentPkg().CurrentVer())
         continue;
       
       if (Cache.VS().CheckDep(Ver,D->CompareOp,D.TargetVer()) == false)
         continue;
 
-      if (EarlyRemove(D.ParentPkg()) == false)
+      if (EarlyRemove(D.ParentPkg(), &D) == false)
         return _error->Error("Reverse conflicts early remove for package '%s' failed",
                              Pkg.FullName().c_str());
    }
    return true;
 }
                                                                        /*}}}*/
+// PM::CheckRBreaks - Look for reverse breaks                          /*{{{*/
+bool pkgPackageManager::CheckRBreaks(PkgIterator const &Pkg, DepIterator D,
+                                    const char * const Ver)
+{
+   for (;D.end() == false; ++D)
+   {
+      if (D->Type != pkgCache::Dep::DpkgBreaks)
+        continue;
+
+      PkgIterator const DP = D.ParentPkg();
+      if (Cache[DP].Delete() == false)
+        continue;
+
+      // Ignore self conflicts, ignore conflicts from irrelevant versions
+      if (D.IsIgnorable(Pkg) || D.ParentVer() != DP.CurrentVer())
+        continue;
+
+      if (Cache.VS().CheckDep(Ver, D->CompareOp, D.TargetVer()) == false)
+        continue;
+
+      // no earlyremove() here as user has already agreed to the permanent removal
+      if (SmartRemove(DP) == false)
+        return _error->Error("Internal Error, Could not early remove %s (%d)",DP.FullName().c_str(), 4);
+   }
+   return true;
+}
+                                                                       /*}}}*/
 // PM::ConfigureAll - Run the all out configuration                    /*{{{*/
 // ---------------------------------------------------------------------
 /* This configures every package. It is assumed they are all unpacked and
@@ -279,8 +315,8 @@ bool pkgPackageManager::ConfigureAll()
    if (OList.OrderConfigure() == false)
       return false;
 
-   std::string const conf = _config->Find("PackageManager::Configure","all");
-   bool const ConfigurePkgs = (conf == "all");
+   std::string const conf = _config->Find("PackageManager::Configure", "smart");
+   bool const ConfigurePkgs = (ImmConfigureAll || conf == "all");
 
    // Perform the configuring
    for (pkgOrderList::iterator I = OList.begin(); I != OList.end(); ++I)
@@ -306,18 +342,41 @@ bool pkgPackageManager::ConfigureAll()
    return true;
 }
                                                                        /*}}}*/
+// PM::NonLoopingSmart - helper to avoid loops while calling Smart methods /*{{{*/
+// -----------------------------------------------------------------------
+/* ensures that a loop of the form A depends B, B depends A (and similar)
+   is not leading us down into infinite recursion segfault land */
+bool pkgPackageManager::NonLoopingSmart(SmartAction const action, pkgCache::PkgIterator &Pkg,
+      pkgCache::PkgIterator DepPkg, int const Depth, bool const PkgLoop,
+      bool * const Bad, bool * const Changed)
+{
+   if (PkgLoop == false)
+      List->Flag(Pkg,pkgOrderList::Loop);
+   bool success = false;
+   switch(action)
+   {
+      case UNPACK_IMMEDIATE: success = SmartUnPack(DepPkg, true, Depth + 1); break;
+      case UNPACK: success = SmartUnPack(DepPkg, false, Depth + 1); break;
+      case CONFIGURE: success = SmartConfigure(DepPkg, Depth + 1); break;
+   }
+   if (PkgLoop == false)
+      List->RmFlag(Pkg,pkgOrderList::Loop);
+
+   if (success == false)
+      return false;
+
+   if (Bad != NULL)
+      *Bad = false;
+   if (Changed != NULL && List->IsFlag(DepPkg,pkgOrderList::Loop) == false)
+      *Changed = true;
+   return true;
+}
+                                                                       /*}}}*/
 // PM::SmartConfigure - Perform immediate configuration of the pkg     /*{{{*/
 // ---------------------------------------------------------------------
 /* This function tries to put the system in a state where Pkg can be configured.
-   This involves checking each of Pkg's dependanies and unpacking and 
-   configuring packages where needed. 
-   
-   Note on failure: This method can fail, without causing any problems. 
-   This can happen when using Immediate-Configure-All, SmartUnPack may call
-   SmartConfigure, it may fail because of a complex dependancy situation, but
-   a error will only be reported if ConfigureAll fails. This is why some of the
-   messages this function reports on failure (return false;) as just warnings
-   only shown when debuging*/
+   This involves checking each of Pkg's dependencies and unpacking and
+   configuring packages where needed. */
 bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
 {
    // If this is true, only check and correct and dependencies without the Loop flag
@@ -332,9 +391,9 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
    }
 
    VerIterator const instVer = Cache[Pkg].InstVerIter(Cache);
-      
-   /* Because of the ordered list, most dependencies should be unpacked, 
-      however if there is a loop (A depends on B, B depends on A) this will not 
+
+   /* Because of the ordered list, most dependencies should be unpacked,
+      however if there is a loop (A depends on B, B depends on A) this will not
       be the case, so check for dependencies before configuring. */
    bool Bad = false, Changed = false;
    const unsigned int max_loops = _config->FindI("APT::pkgPackageManager::MaxLoopCount", 5000);
@@ -342,6 +401,8 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
    std::list<DepIterator> needConfigure;
    do
    {
+      // Check each dependency and see if anything needs to be done
+      // so that it can be configured
       Changed = false;
       for (DepIterator D = instVer.DependsList(); D.end() == false; )
       {
@@ -349,16 +410,17 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
         pkgCache::DepIterator Start, End;
         D.GlobOr(Start,End);
 
-        if (End->Type != pkgCache::Dep::Depends)
+        if (End->Type != pkgCache::Dep::Depends && End->Type != pkgCache::Dep::PreDepends)
            continue;
         Bad = true;
 
-        // Check for dependencies that have not been unpacked, probably due to loops.
+         // the first pass checks if we its all good, i.e. if we have
+         // to do anything at all
         for (DepIterator Cur = Start; true; ++Cur)
         {
-           SPtrArray<Version *> VList = Cur.AllTargets();
+           std::unique_ptr<Version *[]> VList(Cur.AllTargets());
 
-           for (Version **I = VList; *I != 0; ++I)
+           for (Version **I = VList.get(); *I != 0; ++I)
            {
               VerIterator Ver(Cache,*I);
               PkgIterator DepPkg = Ver.ParentPkg();
@@ -366,7 +428,8 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
               // Check if the current version of the package is available and will satisfy this dependency
               if (DepPkg.CurrentVer() == Ver && List->IsNow(DepPkg) == true &&
                   List->IsFlag(DepPkg,pkgOrderList::Removed) == false &&
-                  DepPkg.State() == PkgIterator::NeedsNothing)
+                  DepPkg.State() == PkgIterator::NeedsNothing &&
+                  (Cache[DepPkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
               {
                  Bad = false;
                  break;
@@ -379,27 +442,71 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
               if (PkgLoop == true)
               {
                  if (Debug)
-                    std::clog << OutputInDepth(Depth) << "Package " << Pkg << " loops in SmartConfigure" << std::endl;
-                 Bad = false;
-                 break;
+                    std::clog << OutputInDepth(Depth) << "Package " << APT::PrettyPkg(&Cache, Pkg) << " loops in SmartConfigure";
+                 if (List->IsFlag(DepPkg,pkgOrderList::UnPacked))
+                    Bad = false;
+                 else if (Debug)
+                    std::clog << ", but it isn't unpacked yet";
+                 if (Debug)
+                    std::clog << std::endl;
               }
-              else
+           }
+
+            if (Cur == End || Bad == false)
+              break;
+         }
+
+         // this dependency is in a good state, so we can stop
+         if (Bad == false)
+         {
+            if (Debug)
+               std::clog << OutputInDepth(Depth) << "Found ok dep " << APT::PrettyPkg(&Cache, Start.TargetPkg()) << std::endl;
+            continue;
+         }
+
+        // Check for dependencies that have not been unpacked, 
+         // probably due to loops.
+        for (DepIterator Cur = Start; true; ++Cur)
+        {
+           std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+
+           for (Version **I = VList.get(); *I != 0; ++I)
+           {
+              VerIterator Ver(Cache,*I);
+              PkgIterator DepPkg = Ver.ParentPkg();
+
+              // Check if the current version of the package is available and will satisfy this dependency
+              if (DepPkg.CurrentVer() == Ver && List->IsNow(DepPkg) == true &&
+                  List->IsFlag(DepPkg,pkgOrderList::Removed) == false &&
+                  DepPkg.State() == PkgIterator::NeedsNothing &&
+                  (Cache[DepPkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+                  continue;
+
+              // Check if the version that is going to be installed will satisfy the dependency
+              if (Cache[DepPkg].InstallVer != *I || List->IsNow(DepPkg) == false)
+                 continue;
+
+              if (PkgLoop == true)
               {
                  if (Debug)
-                    clog << OutputInDepth(Depth) << "Unpacking " << DepPkg.FullName() << " to avoid loop " << Cur << endl;
-                 if (PkgLoop == false)
-                    List->Flag(Pkg,pkgOrderList::Loop);
-                 if (SmartUnPack(DepPkg, true, Depth + 1) == true)
-                 {
+                    std::clog << OutputInDepth(Depth) << "Package " << APT::PrettyPkg(&Cache, Pkg) << " loops in SmartConfigure";
+                 if (List->IsFlag(DepPkg,pkgOrderList::UnPacked))
                     Bad = false;
-                    if (List->IsFlag(DepPkg,pkgOrderList::Loop) == false)
-                       Changed = true;
-                 }
-                 if (PkgLoop == false)
-                    List->RmFlag(Pkg,pkgOrderList::Loop);
-                 if (Bad == false)
-                    break;
+                 else if (Debug)
+                    std::clog << ", but it isn't unpacked yet";
+                 if (Debug)
+                    std::clog << std::endl;
               }
+              else
+              {
+                 if (Debug)
+                    clog << OutputInDepth(Depth) << "Unpacking " << DepPkg.FullName() << " to avoid loop " << APT::PrettyDep(&Cache, Cur) << endl;
+                 if (NonLoopingSmart(UNPACK_IMMEDIATE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+                    return false;
+              }
+               // at this point we either unpacked a Dep or we are in a loop,
+               // no need to unpack a second one
+              break;
            }
 
            if (Cur == End || Bad == false)
@@ -415,6 +522,7 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
          return _error->Error("Internal error: MaxLoopCount reached in SmartUnPack (1) for %s, aborting", Pkg.FullName().c_str());
    } while (Changed == true);
 
+   // now go over anything that needs configuring
    Bad = false, Changed = false, i = 0;
    do
    {
@@ -428,16 +536,16 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
            Discard.GlobOr(Start,End);
         }
 
-        if (End->Type != pkgCache::Dep::Depends)
+        if (End->Type != pkgCache::Dep::Depends && End->Type != pkgCache::Dep::PreDepends)
            continue;
         Bad = true;
 
         // Search for dependencies which are unpacked but aren't configured yet (maybe loops)
         for (DepIterator Cur = Start; true; ++Cur)
         {
-           SPtrArray<Version *> VList = Cur.AllTargets();
+           std::unique_ptr<Version *[]> VList(Cur.AllTargets());
 
-           for (Version **I = VList; *I != 0; ++I)
+           for (Version **I = VList.get(); *I != 0; ++I)
            {
               VerIterator Ver(Cache,*I);
               PkgIterator DepPkg = Ver.ParentPkg();
@@ -454,25 +562,12 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
                    Bad = false;
                    break;
                  }
-                 /* Check for a loop to prevent one forming
-                      If A depends on B and B depends on A, SmartConfigure will
-                      just hop between them if this is not checked. Dont remove the
-                      loop flag after finishing however as loop is already set.
-                      This means that there is another SmartConfigure call for this
-                      package and it will remove the loop flag */
-                 if (PkgLoop == false)
-                    List->Flag(Pkg,pkgOrderList::Loop);
-                 if (SmartConfigure(DepPkg, Depth + 1) == true)
-                 {
-                    Bad = false;
-                    if (List->IsFlag(DepPkg,pkgOrderList::Loop) == false)
-                       Changed = true;
-                 }
-                 if (PkgLoop == false)
-                   List->RmFlag(Pkg,pkgOrderList::Loop);
-                 // If SmartConfigure was succesfull, Bad is false, so break
-                 if (Bad == false)
-                    break;
+                 if (Debug)
+                    std::clog << OutputInDepth(Depth) << "Configure already unpacked " << APT::PrettyPkg(&Cache, DepPkg) << std::endl;
+                 if (NonLoopingSmart(CONFIGURE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+                    return false;
+                 break;
+
               }
               else if (List->IsFlag(DepPkg,pkgOrderList::Configured))
               {
@@ -486,24 +581,29 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
 
 
         if (Bad == true && Changed == false && Debug == true)
-           std::clog << OutputInDepth(Depth) << "Could not satisfy " << *D << std::endl;
+           std::clog << OutputInDepth(Depth) << "Could not satisfy " << APT::PrettyDep(&Cache, *D) << std::endl;
       }
       if (i++ > max_loops)
          return _error->Error("Internal error: MaxLoopCount reached in SmartUnPack (2) for %s, aborting", Pkg.FullName().c_str());
    } while (Changed == true);
-   
-   if (Bad) {
-      if (Debug)
-         _error->Warning(_("Could not configure '%s'. "),Pkg.FullName().c_str());
+
+   if (Bad == true)
+      return _error->Error(_("Could not configure '%s'. "),Pkg.FullName().c_str());
+
+   // Check for reverse conflicts.
+   if (CheckRBreaks(Pkg,Pkg.RevDependsList(), instVer.VerStr()) == false)
       return false;
-   }
-   
+
+   for (PrvIterator P = instVer.ProvidesList(); P.end() == false; ++P)
+      if (Pkg->Group != P.OwnerPkg()->Group)
+        CheckRBreaks(Pkg,P.ParentPkg().RevDependsList(),P.ProvideVersion());
+
    if (PkgLoop) return true;
 
-   static std::string const conf = _config->Find("PackageManager::Configure","all");
+   static std::string const conf = _config->Find("PackageManager::Configure", "smart");
    static bool const ConfigurePkgs = (conf == "all" || conf == "smart");
 
-   if (List->IsFlag(Pkg,pkgOrderList::Configured)) 
+   if (List->IsFlag(Pkg,pkgOrderList::Configured))
       return _error->Error("Internal configure error on '%s'.", Pkg.FullName().c_str());
 
    if (ConfigurePkgs == true && Configure(Pkg) == false)
@@ -520,7 +620,8 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
             Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
              (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
            continue;
-        SmartConfigure(P, (Depth +1));
+        if (SmartConfigure(P, (Depth +1)) == false)
+           return false;
       }
 
    // Sanity Check
@@ -534,29 +635,37 @@ bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
 // ---------------------------------------------------------------------
 /* This is called to deal with conflicts arising from unpacking */
 bool pkgPackageManager::EarlyRemove(PkgIterator Pkg)
+{
+   return EarlyRemove(Pkg, NULL);
+}
+bool pkgPackageManager::EarlyRemove(PkgIterator Pkg, DepIterator const * const Dep)
 {
    if (List->IsNow(Pkg) == false)
       return true;
-        
+
    // Already removed it
    if (List->IsFlag(Pkg,pkgOrderList::Removed) == true)
       return true;
-   
+
    // Woops, it will not be re-installed!
    if (List->IsFlag(Pkg,pkgOrderList::InList) == false)
       return false;
 
+   // these breaks on M-A:same packages can be dealt with. They 'loop' by design
+   if (Dep != NULL && (*Dep)->Type == pkgCache::Dep::DpkgBreaks && Dep->IsMultiArchImplicit() == true)
+      return true;
+
    // Essential packages get special treatment
    bool IsEssential = false;
    if ((Pkg->Flags & pkgCache::Flag::Essential) != 0 ||
        (Pkg->Flags & pkgCache::Flag::Important) != 0)
       IsEssential = true;
 
-   /* Check for packages that are the dependents of essential packages and 
+   /* Check for packages that are the dependents of essential packages and
       promote them too */
    if (Pkg->CurrentVer != 0)
    {
-      for (DepIterator D = Pkg.RevDependsList(); D.end() == false &&
+      for (pkgCache::DepIterator D = Pkg.RevDependsList(); D.end() == false &&
           IsEssential == false; ++D)
         if (D->Type == pkgCache::Dep::Depends || D->Type == pkgCache::Dep::PreDepends)
            if ((D.ParentPkg()->Flags & pkgCache::Flag::Essential) != 0 ||
@@ -573,11 +682,14 @@ bool pkgPackageManager::EarlyRemove(PkgIterator Pkg)
                                "but if you really want to do it, activate the "
                                "APT::Force-LoopBreak option."),Pkg.FullName().c_str());
    }
-   
+   // dpkg will auto-deconfigure it, no need for the big remove hammer
+   else if (Dep != NULL && (*Dep)->Type == pkgCache::Dep::DpkgBreaks)
+      return true;
+
    bool Res = SmartRemove(Pkg);
    if (Cache[Pkg].Delete() == false)
       List->Flag(Pkg,pkgOrderList::Removed,pkgOrderList::States);
-   
+
    return Res;
 }
                                                                        /*}}}*/
@@ -596,7 +708,7 @@ bool pkgPackageManager::SmartRemove(PkgIterator Pkg)
                                                                        /*}}}*/
 // PM::SmartUnPack - Install helper                                    /*{{{*/
 // ---------------------------------------------------------------------
-/* This puts the system in a state where it can Unpack Pkg, if Pkg is allready
+/* This puts the system in a state where it can Unpack Pkg, if Pkg is already
    unpacked, or when it has been unpacked, if Immediate==true it configures it. */
 bool pkgPackageManager::SmartUnPack(PkgIterator Pkg)
 {
@@ -615,18 +727,21 @@ bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int c
         clog << " (replace version " << Pkg.CurrentVer().VerStr() << " with " << InstallVer.VerStr() << ")";
       if (PkgLoop)
         clog << " (Only Perform PreUnpack Checks)";
+      if (Immediate)
+        clog << " immediately";
       clog << endl;
    }
 
    VerIterator const instVer = Cache[Pkg].InstVerIter(Cache);
 
-   /* PreUnpack Checks: This loop checks and attempts to rectify and problems that would prevent the package being unpacked.
+   /* PreUnpack Checks: This loop checks and attempts to rectify any problems that would prevent the package being unpacked.
       It addresses: PreDepends, Conflicts, Obsoletes and Breaks (DpkgBreaks). Any resolutions that do not require it should
       avoid configuration (calling SmartUnpack with Immediate=true), this is because when unpacking some packages with
-      complex dependancy structures, trying to configure some packages while breaking the loops can complicate things .
+      complex dependency structures, trying to configure some packages while breaking the loops can complicate things.
       This will be either dealt with if the package is configured as a dependency of Pkg (if and when Pkg is configured),
       or by the ConfigureAll call at the end of the for loop in OrderInstall. */
-   bool Changed = false;
+   bool SomethingBad = false, Changed = false;
+   bool couldBeTemporaryRemoved = Depth != 0 && List->IsFlag(Pkg,pkgOrderList::Removed) == false;
    const unsigned int max_loops = _config->FindI("APT::pkgPackageManager::MaxLoopCount", 5000);
    unsigned int i = 0;
    do 
@@ -647,15 +762,16 @@ bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int c
            // Look for easy targets: packages that are already okay
            for (DepIterator Cur = Start; Bad == true; ++Cur)
            {
-              SPtrArray<Version *> VList = Cur.AllTargets();
-              for (Version **I = VList; *I != 0; ++I)
+              std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+              for (Version **I = VList.get(); *I != 0; ++I)
               {
                  VerIterator Ver(Cache,*I);
                  PkgIterator Pkg = Ver.ParentPkg();
 
                  // See if the current version is ok
                  if (Pkg.CurrentVer() == Ver && List->IsNow(Pkg) == true &&
-                     Pkg.State() == PkgIterator::NeedsNothing)
+                     Pkg.State() == PkgIterator::NeedsNothing &&
+                     (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
                  {
                     Bad = false;
                     if (Debug)
@@ -670,187 +786,159 @@ bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int c
            // Look for something that could be configured.
            for (DepIterator Cur = Start; Bad == true && Cur.end() == false; ++Cur)
            {
-              SPtrArray<Version *> VList = Cur.AllTargets();
-              for (Version **I = VList; *I != 0; ++I)
+              std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+              for (Version **I = VList.get(); *I != 0; ++I)
               {
                  VerIterator Ver(Cache,*I);
-                 PkgIterator Pkg = Ver.ParentPkg();
+                 PkgIterator DepPkg = Ver.ParentPkg();
 
                  // Not the install version
-                 if (Cache[Pkg].InstallVer != *I ||
-                     (Cache[Pkg].Keep() == true && Pkg.State() == PkgIterator::NeedsNothing))
+                 if (Cache[DepPkg].InstallVer != *I)
                     continue;
 
-                 if (List->IsFlag(Pkg,pkgOrderList::Configured))
+                 if (Cache[DepPkg].Keep() == true && DepPkg.State() == PkgIterator::NeedsNothing &&
+                       (Cache[DepPkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+                    continue;
+
+                 if (List->IsFlag(DepPkg,pkgOrderList::Configured))
                  {
                     Bad = false;
                     break;
                  }
 
                  // check if it needs unpack or if if configure is enough
-                 if (List->IsFlag(Pkg,pkgOrderList::UnPacked) == false)
+                 if (List->IsFlag(DepPkg,pkgOrderList::UnPacked) == false)
                  {
-                    if (Debug)
-                       clog << OutputInDepth(Depth) << "Trying to SmartUnpack " << Pkg.FullName() << endl;
-                    // SmartUnpack with the ImmediateFlag to ensure its really ready
-                    if (SmartUnPack(Pkg, true, Depth + 1) == true)
+                    // two packages pre-depending on each other can't be handled sanely
+                    if (List->IsFlag(DepPkg,pkgOrderList::Loop) && PkgLoop)
                     {
-                       Bad = false;
-                       if (List->IsFlag(Pkg,pkgOrderList::Loop) == false)
-                          Changed = true;
-                       break;
+                       // this isn't an error as there is potential for something else to satisfy it
+                       // (like a provides or an or-group member)
+                       if (Debug)
+                          clog << OutputInDepth(Depth) << "Unpack loop detected between " << DepPkg.FullName() << " and " << Pkg.FullName() << endl;
+                       continue;
                     }
+
+                    if (Debug)
+                       clog << OutputInDepth(Depth) << "Trying to SmartUnpack " << DepPkg.FullName() << endl;
+                    if (NonLoopingSmart(UNPACK_IMMEDIATE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+                       return false;
                  }
                  else
                  {
                     if (Debug)
-                       clog << OutputInDepth(Depth) << "Trying to SmartConfigure " << Pkg.FullName() << endl;
-                    if (SmartConfigure(Pkg, Depth + 1) == true)
-                    {
-                       Bad = false;
-                       if (List->IsFlag(Pkg,pkgOrderList::Loop) == false)
-                          Changed = true;
-                       break;
-                    }
+                       clog << OutputInDepth(Depth) << "Trying to SmartConfigure " << DepPkg.FullName() << endl;
+                    if (NonLoopingSmart(CONFIGURE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+                       return false;
                  }
+                 break;
               }
            }
 
            if (Bad == true)
-           {
-              if (Start == End)
-                 return _error->Error("Couldn't configure pre-depend %s for %s, "
-                                       "probably a dependency cycle.",
-                                       End.TargetPkg().FullName().c_str(),Pkg.FullName().c_str());
-           }
-           else
-              continue;
+              SomethingBad = true;
         }
         else if (End->Type == pkgCache::Dep::Conflicts ||
-                 End->Type == pkgCache::Dep::Obsoletes)
+                 End->Type == pkgCache::Dep::Obsoletes ||
+                 End->Type == pkgCache::Dep::DpkgBreaks)
         {
-           /* Look for conflicts. Two packages that are both in the install
-              state cannot conflict so we don't check.. */
-           SPtrArray<Version *> VList = End.AllTargets();
-           for (Version **I = VList; *I != 0; I++)
+           std::unique_ptr<Version *[]> VList(End.AllTargets());
+           for (Version **I = VList.get(); *I != 0; ++I)
            {
               VerIterator Ver(Cache,*I);
               PkgIterator ConflictPkg = Ver.ParentPkg();
-              VerIterator InstallVer(Cache,Cache[ConflictPkg].InstallVer);
+              if (ConflictPkg.CurrentVer() != Ver)
+              {
+                 if (Debug)
+                    std::clog << OutputInDepth(Depth) << "Ignore not-installed version " << Ver.VerStr() << " of " << ConflictPkg.FullName() << " for " << APT::PrettyDep(&Cache, End) << std::endl;
+                 continue;
+              }
 
-              // See if the current version is conflicting
-              if (ConflictPkg.CurrentVer() == Ver && List->IsNow(ConflictPkg))
+              if (List->IsNow(ConflictPkg) == false)
               {
-                 clog << OutputInDepth(Depth) << Pkg.FullName() << " conflicts with " << ConflictPkg.FullName() << endl;
-                 /* If a loop is not present or has not yet been detected, attempt to unpack packages
-                    to resolve this conflict. If there is a loop present, remove packages to resolve this conflict */
-                 if (List->IsFlag(ConflictPkg,pkgOrderList::Loop) == false)
-                 {
-                    if (Cache[ConflictPkg].Keep() == 0 && Cache[ConflictPkg].InstallVer != 0)
-                    {
-                       if (Debug)
-                          clog << OutputInDepth(Depth) << OutputInDepth(Depth) << "Unpacking " << ConflictPkg.FullName() << " to prevent conflict" << endl;
-                       List->Flag(Pkg,pkgOrderList::Loop);
-                       if (SmartUnPack(ConflictPkg,false, Depth + 1) == true)
-                          if (List->IsFlag(ConflictPkg,pkgOrderList::Loop) == false)
-                             Changed = true;
-                       // Remove loop to allow it to be used later if needed
-                       List->RmFlag(Pkg,pkgOrderList::Loop);
-                    }
-                    else if (EarlyRemove(ConflictPkg) == false)
-                       return _error->Error("Internal Error, Could not early remove %s (1)",ConflictPkg.FullName().c_str());
-                 }
-                 else if (List->IsFlag(ConflictPkg,pkgOrderList::Removed) == false)
+                 if (Debug)
+                    std::clog << OutputInDepth(Depth) << "Ignore already dealt-with version " << Ver.VerStr() << " of " << ConflictPkg.FullName() << " for " << APT::PrettyDep(&Cache, End) << std::endl;
+                 continue;
+              }
+
+              if (List->IsFlag(ConflictPkg,pkgOrderList::Removed) == true)
+              {
+                 if (Debug)
+                    clog << OutputInDepth(Depth) << "Ignoring " << APT::PrettyDep(&Cache, End) << " as " << ConflictPkg.FullName() << "was temporarily removed" << endl;
+                 continue;
+              }
+
+              if (List->IsFlag(ConflictPkg,pkgOrderList::Loop) && PkgLoop)
+              {
+                 if (End->Type == pkgCache::Dep::DpkgBreaks && End.IsMultiArchImplicit() == true)
                  {
                     if (Debug)
-                       clog << OutputInDepth(Depth) << "Because of conficts knot, removing " << ConflictPkg.FullName() << " to conflict violation" << endl;
-                    if (EarlyRemove(ConflictPkg) == false)
-                       return _error->Error("Internal Error, Could not early remove %s (2)",ConflictPkg.FullName().c_str());
+                       clog << OutputInDepth(Depth) << "Because dependency is MultiArchImplicit we ignored looping on: " << APT::PrettyPkg(&Cache, ConflictPkg) << endl;
+                    continue;
                  }
-              }
-           }
-        }
-        else if (End->Type == pkgCache::Dep::DpkgBreaks)
-        {
-           SPtrArray<Version *> VList = End.AllTargets();
-           for (Version **I = VList; *I != 0; ++I)
-           {
-              VerIterator Ver(Cache,*I);
-              PkgIterator BrokenPkg = Ver.ParentPkg();
-              if (BrokenPkg.CurrentVer() != Ver)
-              {
                  if (Debug)
-                    std::clog << OutputInDepth(Depth) << "  Ignore not-installed version " << Ver.VerStr() << " of " << Pkg.FullName() << " for " << End << std::endl;
+                 {
+                    if (End->Type == pkgCache::Dep::DpkgBreaks)
+                       clog << OutputInDepth(Depth) << "Because of breaks knot, deconfigure " << ConflictPkg.FullName() << " temporarily" << endl;
+                    else
+                       clog << OutputInDepth(Depth) << "Because of conflict knot, removing " << ConflictPkg.FullName() << " temporarily" << endl;
+                 }
+                 if (EarlyRemove(ConflictPkg, &End) == false)
+                    return _error->Error("Internal Error, Could not early remove %s (%d)",ConflictPkg.FullName().c_str(), 3);
+                 SomethingBad = true;
                  continue;
               }
 
-              // Check if it needs to be unpacked
-              if (List->IsFlag(BrokenPkg,pkgOrderList::InList) && Cache[BrokenPkg].Delete() == false &&
-                  List->IsNow(BrokenPkg))
+              if (Cache[ConflictPkg].Delete() == false)
               {
-                 if (List->IsFlag(BrokenPkg,pkgOrderList::Loop) && PkgLoop)
+                 if (Debug)
                  {
-                    // This dependancy has already been dealt with by another SmartUnPack on Pkg
-                    break;
+                    clog << OutputInDepth(Depth) << "Unpacking " << ConflictPkg.FullName() << " to avoid " << APT::PrettyDep(&Cache, End);
+                    if (PkgLoop == true)
+                       clog << " (Looping)";
+                    clog << std::endl;
                  }
-                 else
+                 // we would like to avoid temporary removals and all that at best via a simple unpack
+                 _error->PushToStack();
+                 if (NonLoopingSmart(UNPACK, Pkg, ConflictPkg, Depth, PkgLoop, NULL, &Changed) == false)
                  {
-                    // Found a break, so see if we can unpack the package to avoid it
-                    // but do not set loop if another SmartUnPack already deals with it
-                    // Also, avoid it if the package we would unpack pre-depends on this one
-                    VerIterator InstallVer(Cache,Cache[BrokenPkg].InstallVer);
-                    bool circle = false;
-                    for (pkgCache::DepIterator D = InstallVer.DependsList(); D.end() == false; ++D)
+                    // but if it fails ignore this failure and look for alternative ways of solving
+                    if (Debug)
                     {
-                       if (D->Type != pkgCache::Dep::PreDepends)
-                          continue;
-                       SPtrArray<Version *> VL = D.AllTargets();
-                       for (Version **I = VL; *I != 0; ++I)
-                       {
-                          VerIterator V(Cache,*I);
-                          PkgIterator P = V.ParentPkg();
-                          // we are checking for installation as an easy 'protection' against or-groups and (unchosen) providers
-                          if (P != Pkg || (P.CurrentVer() != V && Cache[P].InstallVer != V))
-                             continue;
-                          circle = true;
-                          break;
-                       }
-                       if (circle == true)
-                          break;
+                       clog << OutputInDepth(Depth) << "Avoidance unpack of " << ConflictPkg.FullName() << " failed for " << APT::PrettyDep(&Cache, End) << " ignoring:" << std::endl;
+                       _error->DumpErrors(std::clog, GlobalError::DEBUG, false);
                     }
-                    if (circle == true)
+                    _error->RevertToStack();
+                    // ignorance can only happen if a) one of the offenders is already gone
+                    if (List->IsFlag(ConflictPkg,pkgOrderList::Removed) == true)
                     {
                        if (Debug)
-                          clog << OutputInDepth(Depth) << "  Avoiding " << End << " avoided as " << BrokenPkg.FullName() << " has a pre-depends on " << Pkg.FullName() << std::endl;
-                       continue;
+                          clog << OutputInDepth(Depth) << "But " << ConflictPkg.FullName() << " was temporarily removed in the meantime to satisfy " << APT::PrettyDep(&Cache, End) << endl;
+                    }
+                    else if (List->IsFlag(Pkg,pkgOrderList::Removed) == true)
+                    {
+                       if (Debug)
+                          clog << OutputInDepth(Depth) << "But " << Pkg.FullName() << " was temporarily removed in the meantime to satisfy " <<  APT::PrettyDep(&Cache, End) << endl;
                     }
+                    // or b) we can make one go (removal or dpkg auto-deconfigure)
                     else
                     {
                        if (Debug)
-                       {
-                          clog << OutputInDepth(Depth) << "  Unpacking " << BrokenPkg.FullName() << " to avoid " << End;
-                          if (PkgLoop == true)
-                             clog << " (Looping)";
-                          clog << std::endl;
-                       }
-                       if (PkgLoop == false)
-                          List->Flag(Pkg,pkgOrderList::Loop);
-                       if (SmartUnPack(BrokenPkg, false, Depth + 1) == true)
-                       {
-                          if (List->IsFlag(BrokenPkg,pkgOrderList::Loop) == false)
-                             Changed = true;
-                       }
-                       if (PkgLoop == false)
-                          List->RmFlag(Pkg,pkgOrderList::Loop);
+                          clog << OutputInDepth(Depth) << "So temprorary remove/deconfigure " << ConflictPkg.FullName() << " to satisfy " <<  APT::PrettyDep(&Cache, End) << endl;
+                       if (EarlyRemove(ConflictPkg, &End) == false)
+                          return _error->Error("Internal Error, Could not early remove %s (%d)",ConflictPkg.FullName().c_str(), 2);
                     }
                  }
+                 else
+                    _error->MergeWithStack();
               }
-              // Check if a package needs to be removed
-              else if (Cache[BrokenPkg].Delete() == true && List->IsFlag(BrokenPkg,pkgOrderList::Configured) == false)
+              else
               {
                  if (Debug)
-                    clog << OutputInDepth(Depth) << "  Removing " << BrokenPkg.FullName() << " to avoid " << End << endl;
-                 SmartRemove(BrokenPkg);
+                    clog << OutputInDepth(Depth) << "Removing " << ConflictPkg.FullName() << " now to avoid " << APT::PrettyDep(&Cache, End) << endl;
+                 // no earlyremove() here as user has already agreed to the permanent removal
+                 if (SmartRemove(Pkg) == false)
+                    return _error->Error("Internal Error, Could not early remove %s (%d)",ConflictPkg.FullName().c_str(), 1);
               }
            }
         }
@@ -858,7 +946,17 @@ bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int c
       if (i++ > max_loops)
          return _error->Error("Internal error: APT::pkgPackageManager::MaxLoopCount reached in SmartConfigure for %s, aborting", Pkg.FullName().c_str());
    } while (Changed == true);
-   
+
+   if (SomethingBad == true)
+      return _error->Error("Couldn't configure %s, probably a dependency cycle.", Pkg.FullName().c_str());
+
+   if (couldBeTemporaryRemoved == true && List->IsFlag(Pkg,pkgOrderList::Removed) == true)
+   {
+      if (Debug)
+        std::clog << OutputInDepth(Depth) << "Prevent unpack as " << APT::PrettyPkg(&Cache, Pkg) << " is currently temporarily removed" << std::endl;
+      return true;
+   }
+
    // Check for reverse conflicts.
    if (CheckRConflicts(Pkg,Pkg.RevDependsList(),
                   instVer.VerStr()) == false)
@@ -919,7 +1017,7 @@ bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int c
    if (Immediate == true) {
       // Perform immedate configuration of the package. 
          if (SmartConfigure(Pkg, Depth + 1) == false)
-            _error->Warning(_("Could not perform immediate configuration on '%s'. "
+            _error->Error(_("Could not perform immediate configuration on '%s'. "
                "Please see man 5 apt.conf under APT::Immediate-Configure for details. (%d)"),Pkg.FullName().c_str(),2);
    }
    
@@ -935,10 +1033,22 @@ pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
       return Failed;
 
    Reset();
-   
+
    if (Debug == true)
       clog << "Beginning to order" << endl;
 
+   std::string const planner = _config->Find("APT::Planner", "internal");
+   unsigned int flags = 0;
+   if (_config->FindB("APT::Immediate-Configure", true) == false)
+      flags |= EIPP::Request::NO_IMMEDIATE_CONFIGURATION;
+   else if (_config->FindB("APT::Immediate-Configure-All", false))
+      flags |= EIPP::Request::IMMEDIATE_CONFIGURATION_ALL;
+   else if (_config->FindB("APT::Force-LoopBreak", false))
+      flags |= EIPP::Request::ALLOW_TEMPORARY_REMOVE_OF_ESSENTIALS;
+   auto const ret = EIPP::OrderInstall(planner.c_str(), this, flags, nullptr);
+   if (planner != "internal")
+      return ret ? Completed : Failed;
+
    bool const ordering =
        _config->FindB("PackageManager::UnpackAll",true) ?
                List->OrderUnpack(FileNames) : List->OrderCritical();
@@ -947,7 +1057,7 @@ pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
       _error->Error("Internal ordering error");
       return Failed;
    }
-   
+
    if (Debug == true)
       clog << "Done ordering" << endl;
 
@@ -955,21 +1065,14 @@ pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
    for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
    {
       PkgIterator Pkg(Cache,*I);
-      
+
       if (List->IsNow(Pkg) == false)
       {
-         if (!List->IsFlag(Pkg,pkgOrderList::Configured) && !NoImmConfigure) {
-            if (SmartConfigure(Pkg, 0) == false && Debug)
-               _error->Warning("Internal Error, Could not configure %s",Pkg.FullName().c_str());
-            // FIXME: The above warning message might need changing
-         } else {
-           if (Debug == true)
-              clog << "Skipping already done " << Pkg.FullName() << endl;
-        }
+        if (Debug == true)
+           clog << "Skipping already done " << Pkg.FullName() << endl;
         continue;
-        
       }
-      
+
       if (List->IsMissing(Pkg) == true)
       {
         if (Debug == true)
@@ -1003,7 +1106,7 @@ pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
       DoneSomething = true;
       
       if (ImmConfigureAll) {
-         /* ConfigureAll here to pick up and packages left unconfigured becuase they were unpacked in the 
+         /* ConfigureAll here to pick up and packages left unconfigured because they were unpacked in the
             "PreUnpack Checks" section */
          if (!ConfigureAll())
             return Failed; 
@@ -1033,24 +1136,29 @@ pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
 pkgPackageManager::OrderResult
 pkgPackageManager::DoInstallPostFork(int statusFd)
 {
-      APT::Progress::PackageManager *progress = new
-         APT::Progress::PackageManagerProgressFd(statusFd);
-      pkgPackageManager::OrderResult res = DoInstallPostFork(progress);
-      delete progress;
-      return res;
-   }
+   APT::Progress::PackageManager *progress = new
+      APT::Progress::PackageManagerProgressFd(statusFd);
+   pkgPackageManager::OrderResult res = DoInstallPostFork(progress);
+   delete progress;
+   return res;
+}
                                                                        /*}}}*/
 // PM::DoInstallPostFork - Does install part that happens after the fork /*{{{*/
 // ---------------------------------------------------------------------
 pkgPackageManager::OrderResult 
 pkgPackageManager::DoInstallPostFork(APT::Progress::PackageManager *progress)
 {
-   bool goResult = Go(progress);
+   bool goResult;
+   auto simulation = dynamic_cast<pkgSimulate*>(this);
+   if (simulation == nullptr)
+      goResult = Go(progress);
+   else
+      goResult = simulation->Go2(progress);
    if(goResult == false) 
       return Failed;
    
    return Res;
-};
+}
                                                                        /*}}}*/ 
 // PM::DoInstall - Does the installation                               /*{{{*/
 // ---------------------------------------------------------------------