DepList is supposed to offer the strong exception guarantee, but didn't. Now it should. Includes some fairly slow debug code to check this and throw InternalError if it doesn't work for now.

1 files changed, 32 insertions, 4 deletions

diff --git a/paludis/dep_list.cc b/paludis/dep_list.cc
index 3b5716d..bee59db 100644
--- a/paludis/dep_list.cc
+++ b/paludis/dep_list.cc
@@ -28,6 +28,7 @@
 #include "indirect_iterator.hh"
 #include "iterator_utilities.hh"
 #include "join.hh"
+#include "log.hh"
 #include "match_package.hh"
 #include "package_dep_atom.hh"
 #include "save.hh"
@@ -204,6 +205,10 @@ DepList::add(DepAtom::ConstPointer atom)
 void
 DepList::_add_raw(const DepAtom * const atom)
 {
+    /// \bug VV this is debug code. remove it once we're sure this works
+    std::list<DepListEntry> backup_merge_list(_implementation->merge_list.begin(),
+            _implementation->merge_list.end());
+
     /* keep track of stack depth */
     Save<int> old_stack_depth(&_implementation->stack_depth,
             _implementation->stack_depth + 1);
@@ -212,26 +217,49 @@ DepList::_add_raw(const DepAtom * const atom)
 
     /* we need to make sure that merge_list doesn't get h0rked in the
      * event of a failure. */
-    bool merge_list_was_empty(_implementation->merge_list.empty());
-    std::list<DepListEntry>::iterator save_end, save_first;
+    bool merge_list_was_empty(_implementation->merge_list.empty()), irange_begin_is_begin(false);
+    std::list<DepListEntry>::iterator save_last, save_first, save_irange_begin, save_irange_end;
     if (! merge_list_was_empty)
     {
         save_first = _implementation->merge_list.begin();
-        save_end = previous(_implementation->merge_list.end());
+        save_last = previous(_implementation->merge_list.end());
+
+        save_irange_end = _implementation->merge_list_insert_pos;
+        if (_implementation->merge_list_insert_pos == _implementation->merge_list.begin())
+            irange_begin_is_begin = true;
+        else
+            save_irange_begin = previous(_implementation->merge_list_insert_pos);
     }
 
     try
     {
         atom->accept(this);
     }
+    catch (const InternalError &)
+    {
+        throw;
+    }
     catch (...)
     {
         if (merge_list_was_empty)
             _implementation->merge_list.clear();
         else
         {
-            _implementation->merge_list.erase(next(save_end), _implementation->merge_list.end());
+            _implementation->merge_list.erase(next(save_last), _implementation->merge_list.end());
             _implementation->merge_list.erase(_implementation->merge_list.begin(), save_first);
+            _implementation->merge_list.erase(
+                    irange_begin_is_begin ? _implementation->merge_list.begin() : next(save_irange_begin),
+                    save_irange_end);
+        }
+
+        /// \bug VV this is debug code. remove it once we're sure this works
+        if (backup_merge_list != _implementation->merge_list)
+        {
+            Log::get_instance()->message(ll_warning, "Old merge_list: " + join(backup_merge_list.begin(),
+                        backup_merge_list.end(), " -> "));
+            Log::get_instance()->message(ll_warning, "New merge_list: " + join(_implementation->merge_list.begin(),
+                        _implementation->merge_list.end(), " -> "));
+            throw InternalError(PALUDIS_HERE, "merge list restore failed");
         }
         throw;
     }