]> git.saurik.com Git - apt.git/blobdiff - apt-pkg/acquire-item.cc
edsp: try harder to not generate unneeded error messages
[apt.git] / apt-pkg / acquire-item.cc
index 82ccaff64ebf59adfadb2c9ce48ccd9014560a1c..8c45acdddb9c2117dc4461849c9124c4353ade7e 100644 (file)
 #include <stdio.h>
 #include <ctime>
 #include <sstream>
+#include <numeric>
 
 #include <apti18n.h>
                                                                        /*}}}*/
 
 using namespace std;
 
-static void printHashSumComparision(std::string const &URI, HashStringList const &Expected, HashStringList const &Actual) /*{{{*/
+static void printHashSumComparison(std::string const &URI, HashStringList const &Expected, HashStringList const &Actual) /*{{{*/
 {
    if (_config->FindB("Debug::Acquire::HashSumMismatch", false) == false)
       return;
@@ -85,32 +86,16 @@ static std::string GetKeepCompressedFileName(std::string file, IndexTarget const
    if (Target.KeepCompressed == false)
       return file;
 
-   std::string const CompressionTypes = Target.Option(IndexTarget::COMPRESSIONTYPES);
-   if (CompressionTypes.empty() == false)
+   std::string const KeepCompressedAs = Target.Option(IndexTarget::KEEPCOMPRESSEDAS);
+   if (KeepCompressedAs.empty() == false)
    {
-      std::string const ext = CompressionTypes.substr(0, CompressionTypes.find(' '));
+      std::string const ext = KeepCompressedAs.substr(0, KeepCompressedAs.find(' '));
       if (ext != "uncompressed")
         file.append(".").append(ext);
    }
    return file;
 }
                                                                        /*}}}*/
-static std::string GetCompressedFileName(IndexTarget const &Target, std::string const &Name, std::string const &Ext) /*{{{*/
-{
-   if (Ext.empty() || Ext == "uncompressed")
-      return Name;
-
-   // do not reverify cdrom sources as apt-cdrom may rewrite the Packages
-   // file when its doing the indexcopy
-   if (Target.URI.substr(0,6) == "cdrom:")
-      return Name;
-
-   // adjust DestFile if its compressed on disk
-   if (Target.KeepCompressed == true)
-      return Name + '.' + Ext;
-   return Name;
-}
-                                                                       /*}}}*/
 static std::string GetMergeDiffsPatchFileName(std::string const &Final, std::string const &Patch)/*{{{*/
 {
    // rred expects the patch as $FinalFile.ed.$patchname.gz
@@ -136,6 +121,59 @@ static std::string GetExistingFilename(std::string const &File)            /*{{{*/
    return "";
 }
                                                                        /*}}}*/
+static std::string GetDiffIndexFileName(std::string const &Name)       /*{{{*/
+{
+   return Name + ".diff/Index";
+}
+                                                                       /*}}}*/
+static std::string GetDiffIndexURI(IndexTarget const &Target)          /*{{{*/
+{
+   return Target.URI + ".diff/Index";
+}
+                                                                       /*}}}*/
+
+static void ReportMirrorFailureToCentral(pkgAcquire::Item const &I, std::string const &FailCode, std::string const &Details)/*{{{*/
+{
+   // we only act if a mirror was used at all
+   if(I.UsedMirror.empty())
+      return;
+#if 0
+   std::cerr << "\nReportMirrorFailure: "
+            << UsedMirror
+            << " Uri: " << DescURI()
+            << " FailCode: "
+            << FailCode << std::endl;
+#endif
+   string const report = _config->Find("Methods::Mirror::ProblemReporting",
+                                "/usr/lib/apt/apt-report-mirror-failure");
+   if(!FileExists(report))
+      return;
+
+   std::vector<char const*> const Args = {
+      report.c_str(),
+      I.UsedMirror.c_str(),
+      I.DescURI().c_str(),
+      FailCode.c_str(),
+      Details.c_str(),
+      NULL
+   };
+
+   pid_t pid = ExecFork();
+   if(pid < 0)
+   {
+      _error->Error("ReportMirrorFailure Fork failed");
+      return;
+   }
+   else if(pid == 0)
+   {
+      execvp(Args[0], (char**)Args.data());
+      std::cerr << "Could not exec " << Args[0] << std::endl;
+      _exit(100);
+   }
+   if(!ExecWait(pid, "report-mirror-failure"))
+      _error->Warning("Couldn't report problem to '%s'", report.c_str());
+}
+                                                                       /*}}}*/
 
 static bool MessageInsecureRepository(bool const isError, std::string const &msg)/*{{{*/
 {
@@ -152,14 +190,14 @@ static bool MessageInsecureRepository(bool const isError, std::string const &msg
    _error->Notice("%s", _("See apt-secure(8) manpage for repository creation and user configuration details."));
    return false;
 }
-static bool MessageInsecureRepository(bool const isError, char const * const msg, std::string const &repo)
+static bool APT_NONNULL(2) MessageInsecureRepository(bool const isError, char const * const msg, std::string const &repo)
 {
    std::string m;
    strprintf(m, msg, repo.c_str());
    return MessageInsecureRepository(isError, m);
 }
                                                                        /*}}}*/
-static bool AllowInsecureRepositories(char const * const msg, std::string const &repo,/*{{{*/
+static bool APT_NONNULL(1, 3, 4, 5) AllowInsecureRepositories(char const * const msg, std::string const &repo,/*{{{*/
       metaIndex const * const MetaIndexParser, pkgAcqMetaClearSig * const TransactionManager, pkgAcquire::Item * const I)
 {
    if(MetaIndexParser->GetTrusted() == metaIndex::TRI_YES)
@@ -201,8 +239,7 @@ APT_CONST bool pkgAcqTransactionItem::HashesRequired() const
       we can at least trust them for integrity of the download itself.
       Only repositories without a Release file can (obviously) not have
       hashes – and they are very uncommon and strongly discouraged */
-   return TransactionManager->MetaIndexParser != NULL &&
-      TransactionManager->MetaIndexParser->GetLoadedSuccessfully() == metaIndex::TRI_YES;
+   return TransactionManager->MetaIndexParser->GetLoadedSuccessfully() == metaIndex::TRI_YES;
 }
 HashStringList pkgAcqTransactionItem::GetExpectedHashes() const
 {
@@ -221,12 +258,12 @@ HashStringList pkgAcqMetaBase::GetExpectedHashes() const
 
 APT_CONST bool pkgAcqIndexDiffs::HashesRequired() const
 {
-   /* We don't always have the diff of the downloaded pdiff file.
-      What we have for sure is hashes for the uncompressed file,
-      but rred uncompresses them on the fly while parsing, so not handled here.
-      Hashes are (also) checked while searching for (next) patch to apply. */
+   /* We can't check hashes of rred result as we don't know what the
+      hash of the file will be. We just know the hash of the patch(es),
+      the hash of the file they will apply on and the hash of the resulting
+      file. */
    if (State == StateFetchDiff)
-      return available_patches[0].download_hashes.empty() == false;
+      return true;
    return false;
 }
 HashStringList pkgAcqIndexDiffs::GetExpectedHashes() const
@@ -242,7 +279,7 @@ APT_CONST bool pkgAcqIndexMergeDiffs::HashesRequired() const
       we can check the rred result after all patches are applied as
       we know the expected result rather than potentially apply more patches */
    if (State == StateFetchDiff)
-      return patch.download_hashes.empty() == false;
+      return true;
    return State == StateApplyDiff;
 }
 HashStringList pkgAcqIndexMergeDiffs::GetExpectedHashes() const
@@ -286,14 +323,34 @@ bool pkgAcquire::Item::QueueURI(pkgAcquire::ItemDesc &Item)
    for a hashsum mismatch to happen which helps nobody) */
 bool pkgAcqTransactionItem::QueueURI(pkgAcquire::ItemDesc &Item)
 {
+   if (TransactionManager->State != TransactionStarted)
+   {
+      if (_config->FindB("Debug::Acquire::Transaction", false))
+        std::clog << "Skip " << Target.URI << " as transaction was already dealt with!" << std::endl;
+      return false;
+   }
    std::string const FinalFile = GetFinalFilename();
-   if (TransactionManager != NULL && TransactionManager->IMSHit == true &&
-        FileExists(FinalFile) == true)
+   if (TransactionManager->IMSHit == true && FileExists(FinalFile) == true)
    {
       PartialFile = DestFile = FinalFile;
       Status = StatDone;
       return false;
    }
+   // If we got the InRelease file via a mirror, pick all indexes directly from this mirror, too
+   if (TransactionManager->BaseURI.empty() == false &&
+        URI::SiteOnly(Item.URI) != URI::SiteOnly(TransactionManager->BaseURI))
+   {
+      // this ensures we rewrite only once and only the first step
+      auto const OldBaseURI = Target.Option(IndexTarget::BASE_URI);
+      if (OldBaseURI.empty() == false && APT::String::Startswith(Item.URI, OldBaseURI))
+      {
+        auto const ExtraPath = Item.URI.substr(OldBaseURI.length());
+        Item.URI = flCombine(TransactionManager->BaseURI, ExtraPath);
+        UsedMirror = TransactionManager->UsedMirror;
+        if (Item.Description.find(" ") != string::npos)
+           Item.Description.replace(0, Item.Description.find(" "), UsedMirror);
+      }
+   }
    return pkgAcquire::Item::QueueURI(Item);
 }
 /* The transition manager InRelease itself (or its older sisters-in-law
@@ -316,17 +373,17 @@ bool pkgAcqDiffIndex::QueueURI(pkgAcquire::ItemDesc &Item)
 // Acquire::Item::GetFinalFilename and specialisations for child classes       /*{{{*/
 std::string pkgAcquire::Item::GetFinalFilename() const
 {
+   // Beware: Desc.URI is modified by redirections
    return GetFinalFileNameFromURI(Desc.URI);
 }
 std::string pkgAcqDiffIndex::GetFinalFilename() const
 {
-   // the logic we inherent from pkgAcqBaseIndex isn't what we need here
-   return pkgAcquire::Item::GetFinalFilename();
+   return GetFinalFileNameFromURI(GetDiffIndexURI(Target));
 }
 std::string pkgAcqIndex::GetFinalFilename() const
 {
    std::string const FinalFile = GetFinalFileNameFromURI(Target.URI);
-   return GetCompressedFileName(Target, FinalFile, CurrentCompressionExtension);
+   return GetKeepCompressedFileName(FinalFile, Target);
 }
 std::string pkgAcqMetaSig::GetFinalFilename() const
 {
@@ -358,7 +415,7 @@ std::string pkgAcqIndex::GetMetaKey() const
 }
 std::string pkgAcqDiffIndex::GetMetaKey() const
 {
-   return Target.MetaKey + ".diff/Index";
+   return GetDiffIndexFileName(Target.MetaKey);
 }
                                                                        /*}}}*/
 //pkgAcqTransactionItem::TransactionState and specialisations for child classes        /*{{{*/
@@ -367,6 +424,7 @@ bool pkgAcqTransactionItem::TransactionState(TransactionStates const state)
    bool const Debug = _config->FindB("Debug::Acquire::Transaction", false);
    switch(state)
    {
+      case TransactionStarted: _error->Fatal("Item %s changed to invalid transaction start state!", Target.URI.c_str()); break;
       case TransactionAbort:
         if(Debug == true)
            std::clog << "  Cancel: " << DestFile << std::endl;
@@ -379,7 +437,30 @@ bool pkgAcqTransactionItem::TransactionState(TransactionStates const state)
       case TransactionCommit:
         if(PartialFile.empty() == false)
         {
-           if (PartialFile != DestFile)
+           bool sameFile = (PartialFile == DestFile);
+           // we use symlinks on IMS-Hit to avoid copies
+           if (RealFileExists(DestFile))
+           {
+              struct stat Buf;
+              if (lstat(PartialFile.c_str(), &Buf) != -1)
+              {
+                 if (S_ISLNK(Buf.st_mode) && Buf.st_size > 0)
+                 {
+                    char partial[Buf.st_size + 1];
+                    ssize_t const sp = readlink(PartialFile.c_str(), partial, Buf.st_size);
+                    if (sp == -1)
+                       _error->Errno("pkgAcqTransactionItem::TransactionState-sp", _("Failed to readlink %s"), PartialFile.c_str());
+                    else
+                    {
+                       partial[sp] = '\0';
+                       sameFile = (DestFile == partial);
+                    }
+                 }
+              }
+              else
+                 _error->Errno("pkgAcqTransactionItem::TransactionState-stat", _("Failed to stat %s"), PartialFile.c_str());
+           }
+           if (sameFile == false)
            {
               // ensure that even without lists-cleanup all compressions are nuked
               std::string FinalFile = GetFinalFileNameFromURI(Target.URI);
@@ -412,7 +493,7 @@ bool pkgAcqTransactionItem::TransactionState(TransactionStates const state)
         } else {
            if(Debug == true)
               std::clog << "rm " << DestFile << " # " << DescURI() << std::endl;
-           if (RemoveFile("TransactionCommit", DestFile) == false)
+           if (RemoveFile("TransItem::TransactionCommit", DestFile) == false)
               return false;
         }
         break;
@@ -433,6 +514,7 @@ bool pkgAcqIndex::TransactionState(TransactionStates const state)
 
    switch (state)
    {
+      case TransactionStarted: _error->Fatal("AcqIndex %s changed to invalid transaction start state!", Target.URI.c_str()); break;
       case TransactionAbort:
         if (Stage == STAGE_DECOMPRESS_AND_VERIFY)
         {
@@ -444,7 +526,7 @@ bool pkgAcqIndex::TransactionState(TransactionStates const state)
         break;
       case TransactionCommit:
         if (EraseFileName.empty() == false)
-           RemoveFile("TransactionCommit", EraseFileName);
+           RemoveFile("AcqIndex::TransactionCommit", EraseFileName);
         break;
    }
    return true;
@@ -456,6 +538,7 @@ bool pkgAcqDiffIndex::TransactionState(TransactionStates const state)
 
    switch (state)
    {
+      case TransactionStarted: _error->Fatal("Item %s changed to invalid transaction start state!", Target.URI.c_str()); break;
       case TransactionCommit:
         break;
       case TransactionAbort:
@@ -492,6 +575,41 @@ class APT_HIDDEN NoActionItem : public pkgAcquire::Item                    /*{{{*/
    }
 };
                                                                        /*}}}*/
+class APT_HIDDEN CleanupItem : public pkgAcqTransactionItem            /*{{{*/
+/* This class ensures that a file which was configured but isn't downloaded
+   for various reasons isn't kept in an old version in the lists directory.
+   In a way its the reverse of NoActionItem as it helps with removing files
+   even if the lists-cleanup is deactivated. */
+{
+   public:
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI;};
+   virtual HashStringList GetExpectedHashes()  const APT_OVERRIDE {return HashStringList();};
+
+   CleanupItem(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager, IndexTarget const &Target) :
+      pkgAcqTransactionItem(Owner, TransactionManager, Target)
+   {
+      Status = StatDone;
+      DestFile = GetFinalFileNameFromURI(Target.URI);
+   }
+   bool TransactionState(TransactionStates const state) APT_OVERRIDE
+   {
+      switch (state)
+      {
+        case TransactionStarted:
+           break;
+        case TransactionAbort:
+           break;
+        case TransactionCommit:
+           if (_config->FindB("Debug::Acquire::Transaction", false) == true)
+              std::clog << "rm " << DestFile << " # " << DescURI() << std::endl;
+           if (RemoveFile("TransItem::TransactionCommit", DestFile) == false)
+              return false;
+           break;
+      }
+      return true;
+   }
+};
+                                                                       /*}}}*/
 
 // Acquire::Item::Item - Constructor                                   /*{{{*/
 APT_IGNORE_DEPRECATED_PUSH
@@ -545,8 +663,6 @@ APT_CONST bool pkgAcquire::Item::IsTrusted() const                  /*{{{*/
    fetch this object */
 void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
 {
-   if(ErrorText.empty())
-      ErrorText = LookupTag(Message,"Message");
    if (QueueCounter <= 1)
    {
       /* This indicates that the file is not available right now but might
@@ -577,16 +693,63 @@ void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig con
    }
 
    string const FailReason = LookupTag(Message, "FailReason");
-   if (FailReason == "MaximumSizeExceeded")
-      RenameOnError(MaximumSizeExceeded);
+   enum { MAXIMUM_SIZE_EXCEEDED, HASHSUM_MISMATCH, OTHER } failreason = OTHER;
+   if ( FailReason == "MaximumSizeExceeded")
+      failreason = MAXIMUM_SIZE_EXCEEDED;
    else if (Status == StatAuthError)
-      RenameOnError(HashSumMismatch);
+      failreason = HASHSUM_MISMATCH;
+
+   if(ErrorText.empty())
+   {
+      if (Status == StatAuthError)
+      {
+        std::ostringstream out;
+        switch (failreason)
+        {
+           case HASHSUM_MISMATCH:
+              out << _("Hash Sum mismatch") << std::endl;
+              break;
+           case MAXIMUM_SIZE_EXCEEDED:
+           case OTHER:
+              out << LookupTag(Message, "Message") << std::endl;
+              break;
+        }
+        auto const ExpectedHashes = GetExpectedHashes();
+        if (ExpectedHashes.empty() == false)
+        {
+           out << "Hashes of expected file:" << std::endl;
+           for (auto const &hs: ExpectedHashes)
+              out << " - " << hs.toStr() << std::endl;
+        }
+        if (failreason == HASHSUM_MISMATCH)
+        {
+           out << "Hashes of received file:" << std::endl;
+           for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
+           {
+              std::string const tagname = std::string(*type) + "-Hash";
+              std::string const hashsum = LookupTag(Message, tagname.c_str());
+              if (hashsum.empty() == false)
+                 out << " - " << HashString(*type, hashsum).toStr() << std::endl;
+           }
+           out << "Last modification reported: " << LookupTag(Message, "Last-Modified", "<none>") << std::endl;
+        }
+        ErrorText = out.str();
+      }
+      else
+        ErrorText = LookupTag(Message,"Message");
+   }
+
+   switch (failreason)
+   {
+      case MAXIMUM_SIZE_EXCEEDED: RenameOnError(MaximumSizeExceeded); break;
+      case HASHSUM_MISMATCH: RenameOnError(HashSumMismatch); break;
+      case OTHER: break;
+   }
 
-   // report mirror failure back to LP if we actually use a mirror
    if (FailReason.empty() == false)
-      ReportMirrorFailure(FailReason);
+      ReportMirrorFailureToCentral(*this, FailReason, ErrorText);
    else
-      ReportMirrorFailure(ErrorText);
+      ReportMirrorFailureToCentral(*this, ErrorText, ErrorText);
 
    if (QueueCounter > 1)
       Status = StatIdle;
@@ -674,13 +837,10 @@ bool pkgAcquire::Item::RenameOnError(pkgAcquire::Item::RenameOnErrorState const
    {
       case HashSumMismatch:
         errtext = _("Hash Sum mismatch");
-        Status = StatAuthError;
-        ReportMirrorFailure("HashChecksumFailure");
         break;
       case SizeMismatch:
         errtext = _("Size mismatch");
         Status = StatAuthError;
-        ReportMirrorFailure("SizeFailure");
         break;
       case InvalidFormat:
         errtext = _("Invalid file format");
@@ -697,7 +857,6 @@ bool pkgAcquire::Item::RenameOnError(pkgAcquire::Item::RenameOnErrorState const
         break;
       case MaximumSizeExceeded:
         // the method is expected to report a good error for this
-        Status = StatError;
         break;
       case PDiffError:
         // no handling here, done by callers
@@ -715,47 +874,9 @@ void pkgAcquire::Item::SetActiveSubprocess(const std::string &subprocess)/*{{{*/
 }
                                                                        /*}}}*/
 // Acquire::Item::ReportMirrorFailure                                  /*{{{*/
-void pkgAcquire::Item::ReportMirrorFailure(string const &FailCode)
+void pkgAcquire::Item::ReportMirrorFailure(std::string const &FailCode)
 {
-   // we only act if a mirror was used at all
-   if(UsedMirror.empty())
-      return;
-#if 0
-   std::cerr << "\nReportMirrorFailure: " 
-            << UsedMirror
-            << " Uri: " << DescURI()
-            << " FailCode: " 
-            << FailCode << std::endl;
-#endif
-   string report = _config->Find("Methods::Mirror::ProblemReporting", 
-                                "/usr/lib/apt/apt-report-mirror-failure");
-   if(!FileExists(report))
-      return;
-
-   std::vector<char const*> Args;
-   Args.push_back(report.c_str());
-   Args.push_back(UsedMirror.c_str());
-   Args.push_back(DescURI().c_str());
-   Args.push_back(FailCode.c_str());
-   Args.push_back(NULL);
-
-   pid_t pid = ExecFork();
-   if(pid < 0)
-   {
-      _error->Error("ReportMirrorFailure Fork failed");
-      return;
-   }
-   else if(pid == 0)
-   {
-      execvp(Args[0], (char**)Args.data());
-      std::cerr << "Could not exec " << Args[0] << std::endl;
-      _exit(100);
-   }
-   if(!ExecWait(pid, "report-mirror-failure"))
-   {
-      _error->Warning("Couldn't report problem to '%s'",
-                     _config->Find("Methods::Mirror::ProblemReporting").c_str());
-   }
+   ReportMirrorFailureToCentral(*this, FailCode, FailCode);
 }
                                                                        /*}}}*/
 std::string pkgAcquire::Item::HashSum() const                          /*{{{*/
@@ -784,14 +905,38 @@ HashStringList pkgAcqTransactionItem::GetExpectedHashesFor(std::string const &Me
 }
                                                                        /*}}}*/
 
+static void LoadLastMetaIndexParser(pkgAcqMetaClearSig * const TransactionManager, std::string const &FinalRelease, std::string const &FinalInRelease)/*{{{*/
+{
+   if (TransactionManager->IMSHit == true)
+      return;
+   if (RealFileExists(FinalInRelease) || RealFileExists(FinalRelease))
+   {
+      TransactionManager->LastMetaIndexParser = TransactionManager->MetaIndexParser->UnloadedClone();
+      if (TransactionManager->LastMetaIndexParser != NULL)
+      {
+        _error->PushToStack();
+        if (RealFileExists(FinalInRelease))
+           TransactionManager->LastMetaIndexParser->Load(FinalInRelease, NULL);
+        else
+           TransactionManager->LastMetaIndexParser->Load(FinalRelease, NULL);
+        // its unlikely to happen, but if what we have is bad ignore it
+        if (_error->PendingError())
+        {
+           delete TransactionManager->LastMetaIndexParser;
+           TransactionManager->LastMetaIndexParser = NULL;
+        }
+        _error->RevertToStack();
+      }
+   }
+}
+                                                                       /*}}}*/
+
 // AcqMetaBase - Constructor                                           /*{{{*/
 pkgAcqMetaBase::pkgAcqMetaBase(pkgAcquire * const Owner,
       pkgAcqMetaClearSig * const TransactionManager,
-      std::vector<IndexTarget> const &IndexTargets,
       IndexTarget const &DataTarget)
 : pkgAcqTransactionItem(Owner, TransactionManager, DataTarget), d(NULL),
-   IndexTargets(IndexTargets),
-   AuthPass(false), IMSHit(false)
+   AuthPass(false), IMSHit(false), State(TransactionStarted)
 {
 }
                                                                        /*}}}*/
@@ -807,10 +952,20 @@ void pkgAcqMetaBase::AbortTransaction()
    if(_config->FindB("Debug::Acquire::Transaction", false) == true)
       std::clog << "AbortTransaction: " << TransactionManager << std::endl;
 
+   switch (TransactionManager->State)
+   {
+      case TransactionStarted: break;
+      case TransactionAbort: _error->Fatal("Transaction %s was already aborted and is aborted again", TransactionManager->Target.URI.c_str()); return;
+      case TransactionCommit: _error->Fatal("Transaction %s was already aborted and is now commited", TransactionManager->Target.URI.c_str()); return;
+   }
+   TransactionManager->State = TransactionAbort;
+
    // ensure the toplevel is in error state too
    for (std::vector<pkgAcqTransactionItem*>::iterator I = Transaction.begin();
         I != Transaction.end(); ++I)
    {
+      if ((*I)->Status != pkgAcquire::Item::StatFetching)
+        Owner->Dequeue(*I);
       (*I)->TransactionState(TransactionAbort);
    }
    Transaction.clear();
@@ -840,6 +995,14 @@ void pkgAcqMetaBase::CommitTransaction()
    if(_config->FindB("Debug::Acquire::Transaction", false) == true)
       std::clog << "CommitTransaction: " << this << std::endl;
 
+   switch (TransactionManager->State)
+   {
+      case TransactionStarted: break;
+      case TransactionAbort: _error->Fatal("Transaction %s was already commited and is now aborted", TransactionManager->Target.URI.c_str()); return;
+      case TransactionCommit: _error->Fatal("Transaction %s was already commited and is again commited", TransactionManager->Target.URI.c_str()); return;
+   }
+   TransactionManager->State = TransactionCommit;
+
    // move new files into place *and* remove files that are not
    // part of the transaction but are still on disk
    for (std::vector<pkgAcqTransactionItem*>::iterator I = Transaction.begin();
@@ -868,37 +1031,36 @@ void pkgAcqMetaBase::TransactionStageRemoval(pkgAcqTransactionItem * const I,
 }
                                                                        /*}}}*/
 // AcqMetaBase::GenerateAuthWarning - Check gpg authentication error   /*{{{*/
+/* This method is called from ::Failed handlers. If it returns true,
+   no fallback to other files or modi is performed */
 bool pkgAcqMetaBase::CheckStopAuthentication(pkgAcquire::Item * const I, const std::string &Message)
 {
-   // FIXME: this entire function can do now that we disallow going to
-   //        a unauthenticated state and can cleanly rollback
-
    string const Final = I->GetFinalFilename();
-   if(FileExists(Final))
+   std::string const GPGError = LookupTag(Message, "Message");
+   if (FileExists(Final))
    {
       I->Status = StatTransientNetworkError;
-      _error->Warning(_("An error occurred during the signature "
-                        "verification. The repository is not updated "
-                        "and the previous index files will be used. "
-                        "GPG error: %s: %s"),
-                      Desc.Description.c_str(),
-                      LookupTag(Message,"Message").c_str());
+      _error->Warning(_("An error occurred during the signature verification. "
+              "The repository is not updated and the previous index files will be used. "
+              "GPG error: %s: %s"),
+           Desc.Description.c_str(),
+           GPGError.c_str());
       RunScripts("APT::Update::Auth-Failure");
       return true;
    } else if (LookupTag(Message,"Message").find("NODATA") != string::npos) {
       /* Invalid signature file, reject (LP: #346386) (Closes: #627642) */
       _error->Error(_("GPG error: %s: %s"),
-                    Desc.Description.c_str(),
-                    LookupTag(Message,"Message").c_str());
+           Desc.Description.c_str(),
+           GPGError.c_str());
       I->Status = StatAuthError;
       return true;
    } else {
       _error->Warning(_("GPG error: %s: %s"),
-                      Desc.Description.c_str(),
-                      LookupTag(Message,"Message").c_str());
+           Desc.Description.c_str(),
+           GPGError.c_str());
    }
    // gpgv method failed
-   ReportMirrorFailure("GPGFailure");
+   ReportMirrorFailureToCentral(*this, "GPGFailure", GPGError);
    return false;
 }
                                                                        /*}}}*/
@@ -936,6 +1098,15 @@ bool pkgAcqMetaBase::CheckDownloadDone(pkgAcqTransactionItem * const I, const st
    // We have just finished downloading a Release file (it is not
    // verified yet)
 
+   // Save the final base URI we got this Release file from
+   if (I->UsedMirror.empty() == false && _config->FindB("Acquire::SameMirrorForAllIndexes", true))
+   {
+      if (APT::String::Endswith(I->Desc.URI, "InRelease"))
+        TransactionManager->BaseURI = I->Desc.URI.substr(0, I->Desc.URI.length() - strlen("InRelease"));
+      else if (APT::String::Endswith(I->Desc.URI, "Release"))
+        TransactionManager->BaseURI = I->Desc.URI.substr(0, I->Desc.URI.length() - strlen("Release"));
+   }
+
    std::string const FileName = LookupTag(Message,"Filename");
    if (FileName != I->DestFile && RealFileExists(I->DestFile) == false)
    {
@@ -962,8 +1133,7 @@ bool pkgAcqMetaBase::CheckDownloadDone(pkgAcqTransactionItem * const I, const st
    {
       // for simplicity, the transaction manager is always InRelease
       // even if it doesn't exist.
-      if (TransactionManager != NULL)
-        TransactionManager->IMSHit = true;
+      TransactionManager->IMSHit = true;
       I->PartialFile = I->DestFile = I->GetFinalFilename();
    }
 
@@ -996,25 +1166,7 @@ bool pkgAcqMetaBase::CheckAuthDone(string const &Message)         /*{{{*/
         FinalInRelease = FinalFile.substr(0, FinalFile.length() - strlen("Release")) + "InRelease";
         FinalRelease = FinalFile;
       }
-      if (RealFileExists(FinalInRelease) || RealFileExists(FinalRelease))
-      {
-        TransactionManager->LastMetaIndexParser = TransactionManager->MetaIndexParser->UnloadedClone();
-        if (TransactionManager->LastMetaIndexParser != NULL)
-        {
-           _error->PushToStack();
-           if (RealFileExists(FinalInRelease))
-              TransactionManager->LastMetaIndexParser->Load(FinalInRelease, NULL);
-           else
-              TransactionManager->LastMetaIndexParser->Load(FinalRelease, NULL);
-           // its unlikely to happen, but if what we have is bad ignore it
-           if (_error->PendingError())
-           {
-              delete TransactionManager->LastMetaIndexParser;
-              TransactionManager->LastMetaIndexParser = NULL;
-           }
-           _error->RevertToStack();
-        }
-      }
+      LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
    }
 
    if (TransactionManager->MetaIndexParser->Load(DestFile, &ErrorText) == false)
@@ -1034,91 +1186,115 @@ bool pkgAcqMetaBase::CheckAuthDone(string const &Message)              /*{{{*/
                 << DestFile << std::endl;
 
    // Download further indexes with verification
-   QueueIndexes(true);
+   TransactionManager->QueueIndexes(true);
 
    return true;
 }
                                                                        /*}}}*/
-void pkgAcqMetaBase::QueueIndexes(bool const verify)                   /*{{{*/
+void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                       /*{{{*/
 {
    // at this point the real Items are loaded in the fetcher
    ExpectedAdditionalItems = 0;
 
-  bool metaBaseSupportsByHash = false;
-  if (TransactionManager != NULL && TransactionManager->MetaIndexParser != NULL)
-     metaBaseSupportsByHash = TransactionManager->MetaIndexParser->GetSupportsAcquireByHash();
-
-   for (std::vector <IndexTarget>::iterator Target = IndexTargets.begin();
-        Target != IndexTargets.end();
-        ++Target)
+   std::set<std::string> targetsSeen;
+   bool const metaBaseSupportsByHash = TransactionManager->MetaIndexParser->GetSupportsAcquireByHash();
+   for (auto &Target: TransactionManager->MetaIndexParser->GetIndexTargets())
    {
+      // if we have seen a target which is created-by a target this one here is declared a
+      // fallback to, we skip acquiring the fallback (but we make sure we clean up)
+      if (targetsSeen.find(Target.Option(IndexTarget::FALLBACK_OF)) != targetsSeen.end())
+      {
+        targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+        new CleanupItem(Owner, TransactionManager, Target);
+        continue;
+      }
       // all is an implementation detail. Users shouldn't use this as arch
       // We need this support trickery here as e.g. Debian has binary-all files already,
       // but arch:all packages are still in the arch:any files, so we would waste precious
       // download time, bandwidth and diskspace for nothing, BUT Debian doesn't feature all
       // in the set of supported architectures, so we can filter based on this property rather
       // than invent an entirely new flag we would need to carry for all of eternity.
-      if (Target->Option(IndexTarget::ARCHITECTURE) == "all")
+      if (Target.Option(IndexTarget::ARCHITECTURE) == "all")
       {
-        if (TransactionManager->MetaIndexParser->IsArchitectureSupported("all") == false)
-           continue;
-        if (TransactionManager->MetaIndexParser->IsArchitectureAllSupportedFor(*Target) == false)
+        if (TransactionManager->MetaIndexParser->IsArchitectureSupported("all") == false ||
+              TransactionManager->MetaIndexParser->IsArchitectureAllSupportedFor(Target) == false)
+        {
+           new CleanupItem(Owner, TransactionManager, Target);
            continue;
+        }
       }
 
-      bool trypdiff = Target->OptionBool(IndexTarget::PDIFFS);
+      bool trypdiff = Target.OptionBool(IndexTarget::PDIFFS);
       if (verify == true)
       {
-        if (TransactionManager->MetaIndexParser->Exists(Target->MetaKey) == false)
+        if (TransactionManager->MetaIndexParser->Exists(Target.MetaKey) == false)
         {
            // optional targets that we do not have in the Release file are skipped
-           if (Target->IsOptional)
+           if (Target.IsOptional)
+           {
+              new CleanupItem(Owner, TransactionManager, Target);
               continue;
+           }
 
-           std::string const &arch = Target->Option(IndexTarget::ARCHITECTURE);
+           std::string const &arch = Target.Option(IndexTarget::ARCHITECTURE);
            if (arch.empty() == false)
            {
               if (TransactionManager->MetaIndexParser->IsArchitectureSupported(arch) == false)
               {
+                 new CleanupItem(Owner, TransactionManager, Target);
                  _error->Notice(_("Skipping acquire of configured file '%s' as repository '%s' doesn't support architecture '%s'"),
-                       Target->MetaKey.c_str(), TransactionManager->Target.Description.c_str(), arch.c_str());
+                       Target.MetaKey.c_str(), TransactionManager->Target.Description.c_str(), arch.c_str());
                  continue;
               }
               // if the architecture is officially supported but currently no packages for it available,
               // ignore silently as this is pretty much the same as just shipping an empty file.
               // if we don't know which architectures are supported, we do NOT ignore it to notify user about this
               if (TransactionManager->MetaIndexParser->IsArchitectureSupported("*undefined*") == false)
+              {
+                 new CleanupItem(Owner, TransactionManager, Target);
                  continue;
+              }
            }
 
            Status = StatAuthError;
-           strprintf(ErrorText, _("Unable to find expected entry '%s' in Release file (Wrong sources.list entry or malformed file)"), Target->MetaKey.c_str());
+           strprintf(ErrorText, _("Unable to find expected entry '%s' in Release file (Wrong sources.list entry or malformed file)"), Target.MetaKey.c_str());
            return;
         }
         else
         {
-           auto const hashes = GetExpectedHashesFor(Target->MetaKey);
-           if (hashes.usable() == false && hashes.empty() == false)
+           auto const hashes = GetExpectedHashesFor(Target.MetaKey);
+           if (hashes.empty() == false)
            {
-              _error->Warning(_("Skipping acquire of configured file '%s' as repository '%s' provides only weak security information for it"),
-                       Target->MetaKey.c_str(), TransactionManager->Target.Description.c_str());
-              continue;
+              if (hashes.usable() == false)
+              {
+                 new CleanupItem(Owner, TransactionManager, Target);
+                 _error->Warning(_("Skipping acquire of configured file '%s' as repository '%s' provides only weak security information for it"),
+                       Target.MetaKey.c_str(), TransactionManager->Target.Description.c_str());
+                 continue;
+              }
+              // empty files are skipped as acquiring the very small compressed files is a waste of time
+              else if (hashes.FileSize() == 0)
+              {
+                 new CleanupItem(Owner, TransactionManager, Target);
+                 targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+                 continue;
+              }
            }
         }
 
         // autoselect the compression method
-        std::vector<std::string> types = VectorizeString(Target->Option(IndexTarget::COMPRESSIONTYPES), ' ');
+        std::vector<std::string> types = VectorizeString(Target.Option(IndexTarget::COMPRESSIONTYPES), ' ');
         types.erase(std::remove_if(types.begin(), types.end(), [&](std::string const &t) {
            if (t == "uncompressed")
-              return TransactionManager->MetaIndexParser->Exists(Target->MetaKey) == false;
-           std::string const MetaKey = Target->MetaKey + "." + t;
+              return TransactionManager->MetaIndexParser->Exists(Target.MetaKey) == false;
+           std::string const MetaKey = Target.MetaKey + "." + t;
            return TransactionManager->MetaIndexParser->Exists(MetaKey) == false;
         }), types.end());
         if (types.empty() == false)
         {
            std::ostringstream os;
            // add the special compressiontype byhash first if supported
-           std::string const useByHashConf = Target->Option(IndexTarget::BY_HASH);
+           std::string const useByHashConf = Target.Option(IndexTarget::BY_HASH);
            bool useByHash = false;
            if(useByHashConf == "force")
               useByHash = true;
@@ -1128,12 +1304,12 @@ void pkgAcqMetaBase::QueueIndexes(bool const verify)                    /*{{{*/
               os << "by-hash ";
            std::copy(types.begin(), types.end()-1, std::ostream_iterator<std::string>(os, " "));
            os << *types.rbegin();
-           Target->Options["COMPRESSIONTYPES"] = os.str();
+           Target.Options["COMPRESSIONTYPES"] = os.str();
         }
         else
-           Target->Options["COMPRESSIONTYPES"].clear();
+           Target.Options["COMPRESSIONTYPES"].clear();
 
-        std::string filename = GetExistingFilename(GetFinalFileNameFromURI(Target->URI));
+        std::string filename = GetExistingFilename(GetFinalFileNameFromURI(Target.URI));
         if (filename.empty() == false)
         {
            // if the Release file is a hit and we have an index it must be the current one
@@ -1144,8 +1320,8 @@ void pkgAcqMetaBase::QueueIndexes(bool const verify)                      /*{{{*/
               // see if the file changed since the last Release file
               // we use the uncompressed files as we might compress differently compared to the server,
               // so the hashes might not match, even if they contain the same data.
-              HashStringList const newFile = GetExpectedHashesFromFor(TransactionManager->MetaIndexParser, Target->MetaKey);
-              HashStringList const oldFile = GetExpectedHashesFromFor(TransactionManager->LastMetaIndexParser, Target->MetaKey);
+              HashStringList const newFile = GetExpectedHashesFromFor(TransactionManager->MetaIndexParser, Target.MetaKey);
+              HashStringList const oldFile = GetExpectedHashesFromFor(TransactionManager->LastMetaIndexParser, Target.MetaKey);
               if (newFile != oldFile)
                  filename.clear();
            }
@@ -1157,57 +1333,42 @@ void pkgAcqMetaBase::QueueIndexes(bool const verify)                    /*{{{*/
 
         if (filename.empty() == false)
         {
-           new NoActionItem(Owner, *Target, filename);
-           std::string const idxfilename = GetFinalFileNameFromURI(Target->URI + ".diff/Index");
+           new NoActionItem(Owner, Target, filename);
+           std::string const idxfilename = GetFinalFileNameFromURI(GetDiffIndexURI(Target));
            if (FileExists(idxfilename))
-              new NoActionItem(Owner, *Target, idxfilename);
+              new NoActionItem(Owner, Target, idxfilename);
+           targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
            continue;
         }
 
         // check if we have patches available
-        trypdiff &= TransactionManager->MetaIndexParser->Exists(Target->MetaKey + ".diff/Index");
+        trypdiff &= TransactionManager->MetaIndexParser->Exists(GetDiffIndexFileName(Target.MetaKey));
       }
       else
       {
         // if we have no file to patch, no point in trying
-        trypdiff &= (GetExistingFilename(GetFinalFileNameFromURI(Target->URI)).empty() == false);
+        trypdiff &= (GetExistingFilename(GetFinalFileNameFromURI(Target.URI)).empty() == false);
       }
 
       // no point in patching from local sources
       if (trypdiff)
       {
-        std::string const proto = Target->URI.substr(0, strlen("file:/"));
+        std::string const proto = Target.URI.substr(0, strlen("file:/"));
         if (proto == "file:/" || proto == "copy:/" || proto == "cdrom:")
            trypdiff = false;
       }
 
       // Queue the Index file (Packages, Sources, Translation-$foo, …)
+      targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
       if (trypdiff)
-         new pkgAcqDiffIndex(Owner, TransactionManager, *Target);
+         new pkgAcqDiffIndex(Owner, TransactionManager, Target);
       else
-         new pkgAcqIndex(Owner, TransactionManager, *Target);
+         new pkgAcqIndex(Owner, TransactionManager, Target);
    }
 }
                                                                        /*}}}*/
-bool pkgAcqMetaBase::VerifyVendor(string const &Message)               /*{{{*/
+bool pkgAcqMetaBase::VerifyVendor(string const &)                      /*{{{*/
 {
-   string::size_type pos;
-
-   // check for missing sigs (that where not fatal because otherwise we had
-   // bombed earlier)
-   string missingkeys;
-   string msg = _("There is no public key available for the "
-                 "following key IDs:\n");
-   pos = Message.find("NO_PUBKEY ");
-   if (pos != std::string::npos)
-   {
-      string::size_type start = pos+strlen("NO_PUBKEY ");
-      string Fingerprint = Message.substr(start, Message.find("\n")-start);
-      missingkeys += (Fingerprint);
-   }
-   if(!missingkeys.empty())
-      _error->Warning("%s", (msg + missingkeys).c_str());
-
    string Transformed = TransactionManager->MetaIndexParser->GetExpectedDist();
 
    if (Transformed == "../project/experimental")
@@ -1215,7 +1376,7 @@ bool pkgAcqMetaBase::VerifyVendor(string const &Message)          /*{{{*/
       Transformed = "experimental";
    }
 
-   pos = Transformed.rfind('/');
+   auto pos = Transformed.rfind('/');
    if (pos != string::npos)
    {
       Transformed = Transformed.substr(0, pos);
@@ -1294,15 +1455,14 @@ pkgAcqMetaBase::~pkgAcqMetaBase()
 pkgAcqMetaClearSig::pkgAcqMetaClearSig(pkgAcquire * const Owner,       /*{{{*/
       IndexTarget const &ClearsignedTarget,
       IndexTarget const &DetachedDataTarget, IndexTarget const &DetachedSigTarget,
-      std::vector<IndexTarget> const &IndexTargets,
       metaIndex * const MetaIndexParser) :
-   pkgAcqMetaIndex(Owner, this, ClearsignedTarget, DetachedSigTarget, IndexTargets),
+   pkgAcqMetaIndex(Owner, this, ClearsignedTarget, DetachedSigTarget),
    d(NULL), ClearsignedTarget(ClearsignedTarget),
    DetachedDataTarget(DetachedDataTarget),
    MetaIndexParser(MetaIndexParser), LastMetaIndexParser(NULL)
 {
    // index targets + (worst case:) Release/Release.gpg
-   ExpectedAdditionalItems = IndexTargets.size() + 2;
+   ExpectedAdditionalItems = std::numeric_limits<decltype(ExpectedAdditionalItems)>::max();
    TransactionManager->Add(this);
 }
                                                                        /*}}}*/
@@ -1324,6 +1484,15 @@ string pkgAcqMetaClearSig::Custom600Headers() const
    return Header;
 }
                                                                        /*}}}*/
+void pkgAcqMetaClearSig::Finished()                                    /*{{{*/
+{
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "Finished: " << DestFile <<std::endl;
+   if(TransactionManager->State == TransactionStarted &&
+      TransactionManager->TransactionHasError() == false)
+      TransactionManager->CommitTransaction();
+}
+                                                                       /*}}}*/
 bool pkgAcqMetaClearSig::VerifyDone(std::string const &Message,                /*{{{*/
         pkgAcquire::MethodConfig const * const Cnf)
 {
@@ -1367,9 +1536,6 @@ void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig c
 {
    Item::Failed(Message, Cnf);
 
-   // we failed, we will not get additional items from this method
-   ExpectedAdditionalItems = 0;
-
    if (AuthPass == false)
    {
       if (Status == StatAuthError || Status == StatTransientNetworkError)
@@ -1388,7 +1554,7 @@ void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig c
       TransactionManager->TransactionStageRemoval(this, GetFinalFilename());
       Status = StatDone;
 
-      new pkgAcqMetaIndex(Owner, TransactionManager, DetachedDataTarget, DetachedSigTarget, IndexTargets);
+      new pkgAcqMetaIndex(Owner, TransactionManager, DetachedDataTarget, DetachedSigTarget);
    }
    else
    {
@@ -1410,37 +1576,14 @@ void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig c
         string const FinalInRelease = GetFinalFilename();
         Rename(DestFile, PartialRelease);
         TransactionManager->TransactionStageCopy(this, PartialRelease, FinalRelease);
-
-        if (RealFileExists(FinalReleasegpg) || RealFileExists(FinalInRelease))
-        {
-           // open the last Release if we have it
-           if (TransactionManager->IMSHit == false)
-           {
-              TransactionManager->LastMetaIndexParser = TransactionManager->MetaIndexParser->UnloadedClone();
-              if (TransactionManager->LastMetaIndexParser != NULL)
-              {
-                 _error->PushToStack();
-                 if (RealFileExists(FinalInRelease))
-                    TransactionManager->LastMetaIndexParser->Load(FinalInRelease, NULL);
-                 else
-                    TransactionManager->LastMetaIndexParser->Load(FinalRelease, NULL);
-                 // its unlikely to happen, but if what we have is bad ignore it
-                 if (_error->PendingError())
-                 {
-                    delete TransactionManager->LastMetaIndexParser;
-                    TransactionManager->LastMetaIndexParser = NULL;
-                 }
-                 _error->RevertToStack();
-              }
-           }
-        }
+        LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
 
         // we parse the indexes here because at this point the user wanted
         // a repository that may potentially harm him
         if (TransactionManager->MetaIndexParser->Load(PartialRelease, &ErrorText) == false || VerifyVendor(Message) == false)
            /* expired Release files are still a problem you need extra force for */;
         else
-           QueueIndexes(true);
+           TransactionManager->QueueIndexes(true);
       }
    }
 }
@@ -1449,9 +1592,8 @@ void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig c
 pkgAcqMetaIndex::pkgAcqMetaIndex(pkgAcquire * const Owner,             /*{{{*/
                                  pkgAcqMetaClearSig * const TransactionManager,
                                 IndexTarget const &DataTarget,
-                                IndexTarget const &DetachedSigTarget,
-                                vector<IndexTarget> const &IndexTargets) :
-   pkgAcqMetaBase(Owner, TransactionManager, IndexTargets, DataTarget), d(NULL),
+                                IndexTarget const &DetachedSigTarget) :
+   pkgAcqMetaBase(Owner, TransactionManager, DataTarget), d(NULL),
    DetachedSigTarget(DetachedSigTarget)
 {
    if(_config->FindB("Debug::Acquire::Transaction", false) == true)
@@ -1465,9 +1607,6 @@ pkgAcqMetaIndex::pkgAcqMetaIndex(pkgAcquire * const Owner,                /*{{{*/
    Desc.Owner = this;
    Desc.ShortDesc = DataTarget.ShortDesc;
    Desc.URI = DataTarget.URI;
-
-   // we expect more item
-   ExpectedAdditionalItems = IndexTargets.size();
    QueueURI(Desc);
 }
                                                                        /*}}}*/
@@ -1502,19 +1641,10 @@ void pkgAcqMetaIndex::Failed(string const &Message,
       TransactionManager->TransactionStageRemoval(this, GetFinalFilename());
 
       // queue without any kind of hashsum support
-      QueueIndexes(false);
+      TransactionManager->QueueIndexes(false);
    }
 }
                                                                        /*}}}*/
-void pkgAcqMetaIndex::Finished()                                       /*{{{*/
-{
-   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
-      std::clog << "Finished: " << DestFile <<std::endl;
-   if(TransactionManager != NULL &&
-      TransactionManager->TransactionHasError() == false)
-      TransactionManager->CommitTransaction();
-}
-                                                                       /*}}}*/
 std::string pkgAcqMetaIndex::DescURI() const                           /*{{{*/
 {
    return Target.URI;
@@ -1649,29 +1779,7 @@ void pkgAcqMetaSig::Failed(string const &Message,pkgAcquire::MethodConfig const
    // only allow going further if the user explicitly wants it
    if (AllowInsecureRepositories(_("The repository '%s' is not signed."), MetaIndex->Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
    {
-      if (RealFileExists(FinalReleasegpg) || RealFileExists(FinalInRelease))
-      {
-        // open the last Release if we have it
-        if (TransactionManager->IMSHit == false)
-        {
-           TransactionManager->LastMetaIndexParser = TransactionManager->MetaIndexParser->UnloadedClone();
-           if (TransactionManager->LastMetaIndexParser != NULL)
-           {
-              _error->PushToStack();
-              if (RealFileExists(FinalInRelease))
-                 TransactionManager->LastMetaIndexParser->Load(FinalInRelease, NULL);
-              else
-                 TransactionManager->LastMetaIndexParser->Load(FinalRelease, NULL);
-              // its unlikely to happen, but if what we have is bad ignore it
-              if (_error->PendingError())
-              {
-                 delete TransactionManager->LastMetaIndexParser;
-                 TransactionManager->LastMetaIndexParser = NULL;
-              }
-              _error->RevertToStack();
-           }
-        }
-      }
+      LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
 
       // we parse the indexes here because at this point the user wanted
       // a repository that may potentially harm him
@@ -1679,7 +1787,7 @@ void pkgAcqMetaSig::Failed(string const &Message,pkgAcquire::MethodConfig const
       if (MetaIndex->VerifyVendor(Message) == false)
         /* expired Release files are still a problem you need extra force for */;
       else
-        MetaIndex->QueueIndexes(GoodLoad);
+        TransactionManager->QueueIndexes(GoodLoad);
 
       TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, MetaIndex->GetFinalFilename());
    }
@@ -1701,6 +1809,21 @@ pkgAcqBaseIndex::pkgAcqBaseIndex(pkgAcquire * const Owner,
       IndexTarget const &Target)
 : pkgAcqTransactionItem(Owner, TransactionManager, Target), d(NULL)
 {
+}
+                                                                       /*}}}*/
+void pkgAcqBaseIndex::Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
+{
+   pkgAcquire::Item::Failed(Message, Cnf);
+   if (Status != StatAuthError)
+      return;
+
+   ErrorText.append("Release file created at: ");
+   auto const timespec = TransactionManager->MetaIndexParser->GetDate();
+   if (timespec == 0)
+      ErrorText.append("<unknown>");
+   else
+      ErrorText.append(TimeRFC1123(timespec));
+   ErrorText.append("\n");
 }
                                                                        /*}}}*/
 pkgAcqBaseIndex::~pkgAcqBaseIndex() {}
@@ -1717,12 +1840,15 @@ pkgAcqDiffIndex::pkgAcqDiffIndex(pkgAcquire * const Owner,
                                  IndexTarget const &Target)
    : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL), diffs(NULL)
 {
+   // FIXME: Magic number as an upper bound on pdiffs we will reasonably acquire
+   ExpectedAdditionalItems = 40;
+
    Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
 
    Desc.Owner = this;
-   Desc.Description = Target.Description + ".diff/Index";
+   Desc.Description = GetDiffIndexFileName(Target.Description);
    Desc.ShortDesc = Target.ShortDesc;
-   Desc.URI = Target.URI + ".diff/Index";
+   Desc.URI = GetDiffIndexURI(Target);
 
    DestFile = GetPartialFileNameFromURI(Desc.URI);
 
@@ -1761,6 +1887,7 @@ void pkgAcqDiffIndex::QueueOnIMSHit() const                               /*{{{*/
                                                                        /*}}}*/
 bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)      /*{{{*/
 {
+   ExpectedAdditionalItems = 0;
    // failing here is fine: our caller will take care of trying to
    // get the complete file if patching fails
    if(Debug)
@@ -1813,7 +1940,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
       if (Debug == true)
       {
         std::clog << "pkgAcqDiffIndex: " << IndexDiffFile << ": Index has different hashes than parser, probably older, so fail pdiffing" << std::endl;
-         printHashSumComparision(CurrentPackagesFile, ServerHashes, TargetFileHashes);
+         printHashSumComparison(CurrentPackagesFile, ServerHashes, TargetFileHashes);
       }
       return false;
    }
@@ -2014,6 +2141,17 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)        /*{{{*/
       return false;
    }
 
+   for (auto const &patch: available_patches)
+      if (patch.result_hashes.usable() == false ||
+           patch.patch_hashes.usable() == false ||
+           patch.download_hashes.usable() == false)
+      {
+        if (Debug)
+           std::clog << "pkgAcqDiffIndex: " << IndexDiffFile << ": provides no usable hashes for " << patch.file
+              << " so fallback to complete download" << std::endl;
+        return false;
+      }
+
    // patching with too many files is rather slow compared to a fast download
    unsigned long const fileLimit = _config->FindI("Acquire::PDiffs::FileLimit", 0);
    if (fileLimit != 0 && fileLimit < available_patches.size())
@@ -2025,18 +2163,37 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)       /*{{{*/
    }
 
    // calculate the size of all patches we have to get
-   // note that all sizes are uncompressed, while we download compressed files
-   unsigned long long patchesSize = 0;
-   for (std::vector<DiffInfo>::const_iterator cur = available_patches.begin();
-        cur != available_patches.end(); ++cur)
-      patchesSize += cur->patch_hashes.FileSize();
-   unsigned long long const sizeLimit = ServerSize * _config->FindI("Acquire::PDiffs::SizeLimit", 100);
-   if (sizeLimit > 0 && (sizeLimit/100) < patchesSize)
-   {
-      if (Debug)
-        std::clog << "Need " << patchesSize << " bytes (Limit is " << sizeLimit/100
-           << ") so fallback to complete download" << std::endl;
-      return false;
+   unsigned short const sizeLimitPercent = _config->FindI("Acquire::PDiffs::SizeLimit", 100);
+   if (sizeLimitPercent > 0)
+   {
+      unsigned long long downloadSize = std::accumulate(available_patches.begin(),
+           available_patches.end(), 0llu, [](unsigned long long const T, DiffInfo const &I) {
+           return T + I.download_hashes.FileSize();
+           });
+      if (downloadSize != 0)
+      {
+        unsigned long long downloadSizeIdx = 0;
+        auto const types = VectorizeString(Target.Option(IndexTarget::COMPRESSIONTYPES), ' ');
+        for (auto const &t : types)
+        {
+           std::string MetaKey = Target.MetaKey;
+           if (t != "uncompressed")
+              MetaKey += '.' + t;
+           HashStringList const hsl = GetExpectedHashesFor(MetaKey);
+           if (unlikely(hsl.usable() == false))
+              continue;
+           downloadSizeIdx = hsl.FileSize();
+           break;
+        }
+        unsigned long long const sizeLimit = downloadSizeIdx * sizeLimitPercent;
+        if ((sizeLimit/100) < downloadSize)
+        {
+           if (Debug)
+              std::clog << "Need " << downloadSize << " compressed bytes (Limit is " << (sizeLimit/100) << ", "
+                 << "original is " << downloadSizeIdx << ") so fallback to complete download" << std::endl;
+           return false;
+        }
+      }
    }
 
    // we have something, queue the diffs
@@ -2059,22 +2216,35 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)       /*{{{*/
 
    // clean the plate
    {
+      std::string const Final = GetExistingFilename(CurrentPackagesFile);
+      if (unlikely(Final.empty())) // because we wouldn't be called in such a case
+        return false;
       std::string const PartialFile = GetPartialFileNameFromURI(Target.URI);
-      std::vector<std::string> exts = APT::Configuration::getCompressorExtensions();
-      for (auto const &ext : exts)
+      if (FileExists(PartialFile) && RemoveFile("Bootstrap-linking", PartialFile) == false)
+      {
+        if (Debug)
+           std::clog << "Bootstrap-linking for patching " << CurrentPackagesFile
+              << " by removing stale " << PartialFile << " failed!" << std::endl;
+        return false;
+      }
+      for (auto const &ext : APT::Configuration::getCompressorExtensions())
       {
         std::string const Partial = PartialFile + ext;
-        if (FileExists(Partial))
-           RemoveFile("PDiffs-Bootstrap", Partial);
+        if (FileExists(Partial) && RemoveFile("Bootstrap-linking", Partial) == false)
+        {
+           if (Debug)
+              std::clog << "Bootstrap-linking for patching " << CurrentPackagesFile
+                 << " by removing stale " << Partial << " failed!" << std::endl;
+           return false;
+        }
       }
-      std::string const Final = GetExistingFilename(CurrentPackagesFile);
-      if (unlikely(Final.empty())) // because we wouldn't be called in such a case
-        return false;
       std::string const Ext = Final.substr(CurrentPackagesFile.length());
       std::string const Partial = PartialFile + Ext;
       if (symlink(Final.c_str(), Partial.c_str()) != 0)
       {
-        std::clog << "Bootstrap-linking for patching " << CurrentPackagesFile << " by linking " << Final << " to " << Partial << " failed!" << std::endl;
+        if (Debug)
+           std::clog << "Bootstrap-linking for patching " << CurrentPackagesFile
+              << " by linking " << Final << " to " << Partial << " failed!" << std::endl;
         return false;
       }
    }
@@ -2099,8 +2269,9 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
                                                                        /*}}}*/
 void pkgAcqDiffIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
 {
-   Item::Failed(Message,Cnf);
+   pkgAcqBaseIndex::Failed(Message,Cnf);
    Status = StatDone;
+   ExpectedAdditionalItems = 0;
 
    if(Debug)
       std::clog << "pkgAcqDiffIndex failed: " << Desc.URI << " with " << Message << std::endl
@@ -2180,7 +2351,7 @@ pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire * const Owner,
                                                                        /*}}}*/
 void pkgAcqIndexDiffs::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
 {
-   Item::Failed(Message,Cnf);
+   pkgAcqBaseIndex::Failed(Message,Cnf);
    Status = StatDone;
 
    DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
@@ -2385,7 +2556,7 @@ void pkgAcqIndexMergeDiffs::Failed(string const &Message,pkgAcquire::MethodConfi
    if(Debug)
       std::clog << "pkgAcqIndexMergeDiffs failed: " << Desc.URI << " with " << Message << std::endl;
 
-   Item::Failed(Message,Cnf);
+   pkgAcqBaseIndex::Failed(Message,Cnf);
    Status = StatDone;
 
    // check if we are the first to fail, otherwise we are done here
@@ -2393,16 +2564,18 @@ void pkgAcqIndexMergeDiffs::Failed(string const &Message,pkgAcquire::MethodConfi
    for (std::vector<pkgAcqIndexMergeDiffs *>::const_iterator I = allPatches->begin();
         I != allPatches->end(); ++I)
       if ((*I)->State == StateErrorDiff)
+      {
+        State = StateErrorDiff;
         return;
+      }
 
    // first failure means we should fallback
    State = StateErrorDiff;
    if (Debug)
       std::clog << "Falling back to normal index file acquire" << std::endl;
    RenameOnError(PDiffError);
-   std::string const patchname = GetPartialFileNameFromURI(Desc.URI);
-   if (RealFileExists(patchname))
-      Rename(patchname, patchname + ".FAILED");
+   if (RealFileExists(DestFile))
+      Rename(DestFile, DestFile + ".FAILED");
    std::string const UnpatchedFile = GetExistingFilename(GetPartialFileNameFromURI(Target.URI));
    if (UnpatchedFile.empty() == false && FileExists(UnpatchedFile))
       Rename(UnpatchedFile, UnpatchedFile + ".FAILED");
@@ -2418,8 +2591,23 @@ void pkgAcqIndexMergeDiffs::Done(string const &Message, HashStringList const &Ha
 
    Item::Done(Message, Hashes, Cnf);
 
+   if (std::any_of(allPatches->begin(), allPatches->end(),
+           [](pkgAcqIndexMergeDiffs const * const P) { return P->State == StateErrorDiff; }))
+   {
+      if(Debug)
+        std::clog << "Another patch failed already, no point in processing this one." << std::endl;
+      State = StateErrorDiff;
+      return;
+   }
+
    std::string const UncompressedUnpatchedFile = GetPartialFileNameFromURI(Target.URI);
    std::string const UnpatchedFile = GetExistingFilename(UncompressedUnpatchedFile);
+   if (UnpatchedFile.empty())
+   {
+      _error->Fatal("Unpatched file %s doesn't exist (anymore)!", UncompressedUnpatchedFile.c_str());
+      State = StateErrorDiff;
+      return;
+   }
    std::string const PatchFile = GetMergeDiffsPatchFileName(UnpatchedFile, patch.file);
    std::string const PatchedFile = GetKeepCompressedFileName(UncompressedUnpatchedFile, Target);
 
@@ -2532,6 +2720,10 @@ void pkgAcqIndex::Init(string const &URI, string const &URIDesc,
    DestFile = GetPartialFileNameFromURI(URI);
    NextCompressionExtension(CurrentCompressionExtension, CompressionExtensions, false);
 
+   // store file size of the download to ensure the fetcher gives
+   // accurate progress reporting
+   FileSize = GetExpectedHashes().FileSize();
+
    if (CurrentCompressionExtension == "uncompressed")
    {
       Desc.URI = URI;
@@ -2539,7 +2731,7 @@ void pkgAcqIndex::Init(string const &URI, string const &URIDesc,
    else if (CurrentCompressionExtension == "by-hash")
    {
       NextCompressionExtension(CurrentCompressionExtension, CompressionExtensions, true);
-      if(unlikely(TransactionManager->MetaIndexParser == NULL || CurrentCompressionExtension.empty()))
+      if(unlikely(CurrentCompressionExtension.empty()))
         return;
       if (CurrentCompressionExtension != "uncompressed")
       {
@@ -2602,7 +2794,7 @@ string pkgAcqIndex::Custom600Headers() const
 // AcqIndex::Failed - getting the indexfile failed                     /*{{{*/
 void pkgAcqIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
 {
-   Item::Failed(Message,Cnf);
+   pkgAcqBaseIndex::Failed(Message,Cnf);
 
    // authorisation matches will not be fixed by other compression types
    if (Status != StatAuthError)
@@ -2621,20 +2813,6 @@ void pkgAcqIndex::Failed(string const &Message,pkgAcquire::MethodConfig const *
       TransactionManager->AbortTransaction();
 }
                                                                        /*}}}*/
-// AcqIndex::ReverifyAfterIMS - Reverify index after an ims-hit                /*{{{*/
-void pkgAcqIndex::ReverifyAfterIMS()
-{
-   // update destfile to *not* include the compression extension when doing
-   // a reverify (as its uncompressed on disk already)
-   DestFile = GetCompressedFileName(Target, GetPartialFileNameFromURI(Target.URI), CurrentCompressionExtension);
-
-   // copy FinalFile into partial/ so that we check the hash again
-   string FinalFile = GetFinalFilename();
-   Stage = STAGE_DECOMPRESS_AND_VERIFY;
-   Desc.URI = "copy:" + FinalFile;
-   QueueURI(Desc);
-}
-                                                                       /*}}}*/
 // AcqIndex::Done - Finished a fetch                                   /*{{{*/
 // ---------------------------------------------------------------------
 /* This goes through a number of states.. On the initial fetch the
@@ -2651,107 +2829,92 @@ void pkgAcqIndex::Done(string const &Message,
    switch(Stage) 
    {
       case STAGE_DOWNLOAD:
-         StageDownloadDone(Message, Hashes, Cfg);
+         StageDownloadDone(Message);
          break;
       case STAGE_DECOMPRESS_AND_VERIFY:
-         StageDecompressDone(Message, Hashes, Cfg);
+         StageDecompressDone();
          break;
    }
 }
                                                                        /*}}}*/
 // AcqIndex::StageDownloadDone - Queue for decompress and verify       /*{{{*/
-void pkgAcqIndex::StageDownloadDone(string const &Message, HashStringList const &,
-                                    pkgAcquire::MethodConfig const * const)
+void pkgAcqIndex::StageDownloadDone(string const &Message)
 {
+   Local = true;
    Complete = true;
 
-   // Handle the unzipd case
-   std::string FileName = LookupTag(Message,"Alt-Filename");
-   if (FileName.empty() == false)
+   std::string const AltFilename = LookupTag(Message,"Alt-Filename");
+   std::string Filename = LookupTag(Message,"Filename");
+
+   // we need to verify the file against the current Release file again
+   // on if-modfied-since hit to avoid a stale attack against us
+   if(StringToBool(LookupTag(Message,"IMS-Hit"),false) == true)
    {
+      // copy FinalFile into partial/ so that we check the hash again
+      string const FinalFile = GetExistingFilename(GetFinalFileNameFromURI(Target.URI));
+      if (symlink(FinalFile.c_str(), DestFile.c_str()) != 0)
+        _error->WarningE("pkgAcqIndex::StageDownloadDone", "Symlinking final file %s back to %s failed", FinalFile.c_str(), DestFile.c_str());
+      else
+      {
+        EraseFileName = DestFile;
+        Filename = DestFile;
+      }
       Stage = STAGE_DECOMPRESS_AND_VERIFY;
-      Local = true;
-      if (CurrentCompressionExtension != "uncompressed")
-        DestFile.erase(DestFile.length() - (CurrentCompressionExtension.length() + 1));
-      Desc.URI = "copy:" + FileName;
+      Desc.URI = "store:" + Filename;
       QueueURI(Desc);
-      SetActiveSubprocess("copy");
+      SetActiveSubprocess(::URI(Desc.URI).Access);
       return;
    }
-   FileName = LookupTag(Message,"Filename");
-
+   // methods like file:// give us an alternative (uncompressed) file
+   else if (Target.KeepCompressed == false && AltFilename.empty() == false)
+   {
+      Filename = AltFilename;
+      EraseFileName.clear();
+   }
    // Methods like e.g. "file:" will give us a (compressed) FileName that is
    // not the "DestFile" we set, in this case we uncompress from the local file
-   if (FileName != DestFile && RealFileExists(DestFile) == false)
+   else if (Filename != DestFile && RealFileExists(DestFile) == false)
    {
-      Local = true;
-      if (Target.KeepCompressed == true)
-      {
-        // but if we don't keep the uncompress we copy the compressed file first
-        Stage = STAGE_DOWNLOAD;
-        Desc.URI = "copy:" + FileName;
-        QueueURI(Desc);
-        SetActiveSubprocess("copy");
-        return;
-      }
+      // symlinking ensures that the filename can be used for compression detection
+      // that is e.g. needed for by-hash which has no extension over file
+      if (symlink(Filename.c_str(),DestFile.c_str()) != 0)
+        _error->WarningE("pkgAcqIndex::StageDownloadDone", "Symlinking file %s to %s failed", Filename.c_str(), DestFile.c_str());
       else
       {
-        // symlinking ensures that the filename can be used for compression detection
-        // that is e.g. needed for by-hash over file
-        if (symlink(FileName.c_str(),DestFile.c_str()) != 0)
-           _error->WarningE("pkgAcqIndex::StageDownloadDone", "Symlinking file %s to %s failed", FileName.c_str(), DestFile.c_str());
-        else
-        {
-           EraseFileName = DestFile;
-           FileName = DestFile;
-        }
+        EraseFileName = DestFile;
+        Filename = DestFile;
       }
    }
-   else
-      EraseFileName = FileName;
 
-   // we need to verify the file against the current Release file again
-   // on if-modfied-since hit to avoid a stale attack against us
-   if(StringToBool(LookupTag(Message,"IMS-Hit"),false) == true)
-   {
-      // The files timestamp matches, reverify by copy into partial/
-      EraseFileName = "";
-      ReverifyAfterIMS();
-      return;
-   }
-
-   string decompProg = "store";
-   if (Target.KeepCompressed == true)
-   {
-      DestFile = "/dev/null";
-      EraseFileName.clear();
-   }
+   Stage = STAGE_DECOMPRESS_AND_VERIFY;
+   DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
+   if (Filename != DestFile && flExtension(Filename) == flExtension(DestFile))
+      Desc.URI = "copy:" + Filename;
    else
+      Desc.URI = "store:" + Filename;
+   if (DestFile == Filename)
    {
       if (CurrentCompressionExtension == "uncompressed")
-        decompProg = "copy";
-      else
-        DestFile.erase(DestFile.length() - (CurrentCompressionExtension.length() + 1));
+        return StageDecompressDone();
+      DestFile = "/dev/null";
    }
 
+   if (EraseFileName.empty() && Filename != AltFilename)
+      EraseFileName = Filename;
+
    // queue uri for the next stage
-   Stage = STAGE_DECOMPRESS_AND_VERIFY;
-   Desc.URI = decompProg + ":" + FileName;
    QueueURI(Desc);
-   SetActiveSubprocess(decompProg);
+   SetActiveSubprocess(::URI(Desc.URI).Access);
 }
                                                                        /*}}}*/
 // AcqIndex::StageDecompressDone - Final verification                  /*{{{*/
-void pkgAcqIndex::StageDecompressDone(string const &,
-                                      HashStringList const &,
-                                      pkgAcquire::MethodConfig const * const)
+void pkgAcqIndex::StageDecompressDone()
 {
-   if (Target.KeepCompressed == true && DestFile == "/dev/null")
-      DestFile = GetPartialFileNameFromURI(Target.URI + '.' + CurrentCompressionExtension);
+   if (DestFile == "/dev/null")
+      DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
 
    // Done, queue for rename on transaction finished
    TransactionManager->TransactionStageCopy(this, DestFile, GetFinalFilename());
-   return;
 }
                                                                        /*}}}*/
 pkgAcqIndex::~pkgAcqIndex() {}
@@ -3047,9 +3210,14 @@ std::string pkgAcqArchive::ShortDesc() const                             /*{{{*/
 pkgAcqArchive::~pkgAcqArchive() {}
 
 // AcqChangelog::pkgAcqChangelog - Constructors                                /*{{{*/
+class pkgAcqChangelog::Private
+{
+   public:
+   std::string FinalFile;
+};
 pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::VerIterator const &Ver,
       std::string const &DestDir, std::string const &DestFilename) :
-   pkgAcquire::Item(Owner), d(NULL), SrcName(Ver.SourcePkgName()), SrcVersion(Ver.SourceVerStr())
+   pkgAcquire::Item(Owner), d(new pkgAcqChangelog::Private()), SrcName(Ver.SourcePkgName()), SrcVersion(Ver.SourceVerStr())
 {
    Desc.URI = URI(Ver);
    Init(DestDir, DestFilename);
@@ -3058,7 +3226,7 @@ pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::VerIterator
 pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::RlsFileIterator const &RlsFile,
       char const * const Component, char const * const SrcName, char const * const SrcVersion,
       const string &DestDir, const string &DestFilename) :
-   pkgAcquire::Item(Owner), d(NULL), SrcName(SrcName), SrcVersion(SrcVersion)
+   pkgAcquire::Item(Owner), d(new pkgAcqChangelog::Private()), SrcName(SrcName), SrcVersion(SrcVersion)
 {
    Desc.URI = URI(RlsFile, Component, SrcName, SrcVersion);
    Init(DestDir, DestFilename);
@@ -3066,7 +3234,7 @@ pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::RlsFileIter
 pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner,
       std::string const &URI, char const * const SrcName, char const * const SrcVersion,
       const string &DestDir, const string &DestFilename) :
-   pkgAcquire::Item(Owner), d(NULL), SrcName(SrcName), SrcVersion(SrcVersion)
+   pkgAcquire::Item(Owner), d(new pkgAcqChangelog::Private()), SrcName(SrcName), SrcVersion(SrcVersion)
 {
    Desc.URI = URI;
    Init(DestDir, DestFilename);
@@ -3087,30 +3255,44 @@ void pkgAcqChangelog::Init(std::string const &DestDir, std::string const &DestFi
       return;
    }
 
-   if (DestDir.empty())
+   std::string DestFileName;
+   if (DestFilename.empty())
+      DestFileName = flCombine(DestFile, SrcName + ".changelog");
+   else
+      DestFileName = flCombine(DestFile, DestFilename);
+
+   std::string const SandboxUser = _config->Find("APT::Sandbox::User");
+   std::string const systemTemp = GetTempDir(SandboxUser);
+   char tmpname[1000];
+   snprintf(tmpname, sizeof(tmpname), "%s/apt-changelog-XXXXXX", systemTemp.c_str());
+   if (NULL == mkdtemp(tmpname))
    {
-      std::string const SandboxUser = _config->Find("APT::Sandbox::User");
-      std::string const systemTemp = GetTempDir(SandboxUser);
-      char tmpname[100];
-      snprintf(tmpname, sizeof(tmpname), "%s/apt-changelog-XXXXXX", systemTemp.c_str());
-      if (NULL == mkdtemp(tmpname))
+      _error->Errno("mkdtemp", "mkdtemp failed in changelog acquire of %s %s", SrcName.c_str(), SrcVersion.c_str());
+      Status = StatError;
+      return;
+   }
+   TemporaryDirectory = tmpname;
+
+   ChangeOwnerAndPermissionOfFile("Item::QueueURI", TemporaryDirectory.c_str(),
+        SandboxUser.c_str(), "root", 0700);
+
+   DestFile = flCombine(TemporaryDirectory, DestFileName);
+   if (DestDir.empty() == false)
+   {
+      d->FinalFile = flCombine(DestDir, DestFileName);
+      if (RealFileExists(d->FinalFile))
       {
-        _error->Errno("mkdtemp", "mkdtemp failed in changelog acquire of %s %s", SrcName.c_str(), SrcVersion.c_str());
-        Status = StatError;
-        return;
+        FileFd file1, file2;
+        if (file1.Open(DestFile, FileFd::WriteOnly | FileFd::Create | FileFd::Exclusive) &&
+              file2.Open(d->FinalFile, FileFd::ReadOnly) && CopyFile(file2, file1))
+        {
+           struct timeval times[2];
+           times[0].tv_sec = times[1].tv_sec = file2.ModificationTime();
+           times[0].tv_usec = times[1].tv_usec = 0;
+           utimes(DestFile.c_str(), times);
+        }
       }
-      DestFile = TemporaryDirectory = tmpname;
-
-      ChangeOwnerAndPermissionOfFile("Item::QueueURI", DestFile.c_str(),
-                                     SandboxUser.c_str(), "root", 0700);
    }
-   else
-      DestFile = DestDir;
-
-   if (DestFilename.empty())
-      DestFile = flCombine(DestFile, SrcName + ".changelog");
-   else
-      DestFile = flCombine(DestFile, DestFilename);
 
    Desc.ShortDesc = "Changelog";
    strprintf(Desc.Description, "%s %s %s Changelog", URI::SiteOnly(Desc.URI).c_str(), SrcName.c_str(), SrcVersion.c_str());
@@ -3120,16 +3302,47 @@ void pkgAcqChangelog::Init(std::string const &DestDir, std::string const &DestFi
                                                                        /*}}}*/
 std::string pkgAcqChangelog::URI(pkgCache::VerIterator const &Ver)     /*{{{*/
 {
+   std::string const confOnline = "Acquire::Changelogs::AlwaysOnline";
+   bool AlwaysOnline = _config->FindB(confOnline, false);
+   if (AlwaysOnline == false)
+      for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
+      {
+        pkgCache::PkgFileIterator const PF = VF.File();
+        if (PF.Flagged(pkgCache::Flag::NotSource) || PF->Release == 0)
+           continue;
+        pkgCache::RlsFileIterator const RF = PF.ReleaseFile();
+        if (RF->Origin != 0 && _config->FindB(confOnline + "::Origin::" + RF.Origin(), false))
+        {
+           AlwaysOnline = true;
+           break;
+        }
+      }
+   if (AlwaysOnline == false)
+   {
+      pkgCache::PkgIterator const Pkg = Ver.ParentPkg();
+      if (Pkg->CurrentVer != 0 && Pkg.CurrentVer() == Ver)
+      {
+        std::string const basename = std::string("/usr/share/doc/") + Pkg.Name() + "/changelog";
+        std::string const debianname = basename + ".Debian";
+        if (FileExists(debianname))
+           return "copy://" + debianname;
+        else if (FileExists(debianname + ".gz"))
+           return "gzip://" + debianname + ".gz";
+        else if (FileExists(basename))
+           return "copy://" + basename;
+        else if (FileExists(basename + ".gz"))
+           return "gzip://" + basename + ".gz";
+      }
+   }
+
    char const * const SrcName = Ver.SourcePkgName();
    char const * const SrcVersion = Ver.SourceVerStr();
-   pkgCache::PkgFileIterator PkgFile;
    // find the first source for this version which promises a changelog
    for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
    {
       pkgCache::PkgFileIterator const PF = VF.File();
       if (PF.Flagged(pkgCache::Flag::NotSource) || PF->Release == 0)
         continue;
-      PkgFile = PF;
       pkgCache::RlsFileIterator const RF = PF.ReleaseFile();
       std::string const uri = URI(RF, PF.Component(), SrcName, SrcVersion);
       if (uri.empty())
@@ -3226,7 +3439,6 @@ void pkgAcqChangelog::Failed(string const &Message, pkgAcquire::MethodConfig con
       ErrorText = errText;
    else
       ErrorText = errText + " (" + ErrorText + ")";
-   return;
 }
                                                                        /*}}}*/
 // AcqChangelog::Done - Item downloaded OK                             /*{{{*/
@@ -3234,6 +3446,12 @@ void pkgAcqChangelog::Done(string const &Message,HashStringList const &CalcHashe
                      pkgAcquire::MethodConfig const * const Cnf)
 {
    Item::Done(Message,CalcHashes,Cnf);
+   if (d->FinalFile.empty() == false)
+   {
+      if (RemoveFile("pkgAcqChangelog::Done", d->FinalFile) == false ||
+           Rename(DestFile, d->FinalFile) == false)
+        Status = StatError;
+   }
 
    Complete = true;
 }
@@ -3245,6 +3463,7 @@ pkgAcqChangelog::~pkgAcqChangelog()                                       /*{{{*/
       RemoveFile("~pkgAcqChangelog", DestFile);
       rmdir(TemporaryDirectory.c_str());
    }
+   delete d;
 }
                                                                        /*}}}*/