Resolves: tdf#90579 swap_single_to_multi_blocks seems broken

when there is associated data in the src. Its copies those pointers
into the block that will appear in the destination. Then can destroy
the source block, which deletes the contents of those pointers, and
then inserts the new block which has dangling pointers to the deleted
data.

https://gitlab.com/mdds/mdds/merge_requests/2

Change-Id: Id9614d95652c8032b03cb5748a284917043d8d21

external/mdds/UnpackedTarball_mdds.mk

@@ -14,6 +14,7 @@ $(eval $(call gb_UnpackedTarball_set_tarball,mdds,$(MDDS_TARBALL)))
 $(eval $(call gb_UnpackedTarball_set_patchlevel,mdds,0))
 
 $(eval $(call gb_UnpackedTarball_add_patches,mdds,\
+        external/mdds/tdf90579.patch.0 \
 ))
 
 # vim: set noet sw=4 ts=4:

external/mdds/tdf90579.patch.0

@@ -0,0 +1,23 @@
+diff --git a/include/mdds/multi_type_vector_def.inl b/include/mdds/multi_type_vector_def.inl
+index 0e2a15a..fe9c767 100644
+--- include/mdds/multi_type_vector_def.inl
++++ include/mdds/multi_type_vector_def.inl
+@@ -2306,6 +2306,9 @@ void multi_type_vector<_CellBlockFunc, _EventFunc>::swap_single_to_multi_blocks(
+     {
+         // Source range is at the top of a block.
+ 
++        // Shrink the current block by erasing the top part.
++        element_block_func::erase(*blk_src->mp_data, 0, len);
++
+         if (src_tail_len == 0)
+         {
+             // the whole block needs to be replaced.
+@@ -2314,8 +2317,6 @@ void multi_type_vector<_CellBlockFunc, _EventFunc>::swap_single_to_multi_blocks(
+         }
+         else
+         {
+-            // Shrink the current block by erasing the top part.
+-            element_block_func::erase(*blk_src->mp_data, 0, len);
+             blk_src->m_size -= len;
+         }
+