The procedure for migration from pre-0.16 databases ("changesetify") is currently not tested by the automatic testsuite. This is partially because there's pretty good odds that there are no such databases remaining in use (so it doesn't matter if the code works) and partially because generating the necessary database dumps is not easy.

I (Zack) recently attempted to construct such a dump, because I wrote code to discard the obsolete database tables (manifest_certs, manifest_deltas, and manifests) used by pre-roster monotone, and I wanted to make absolutely sure that this code did not destroy data needed to complete a changesetification. (This is partially, but not completely, tested by the existing schema_migration_with_rosterify test case; that test only contains post-changesetify, pre-rosterify test cases, and those use only the manifest_deltas and manifests tables.) Forthwith some notes on just what has to be done.

1. The appropriate version to use to construct a test case is monotone 0.14. Versions 0.15 and 0.16 came out in the middle of the changeset transition, and have interesting bugs that we don't want to deal with. Unfortunately, the code at t:monotone-0.14 requires patches to compile with gcc 4.1 and boost 1.33. The patches are at the bottom of this page.
2. The code for constructing a test repository (from tests/schema_migration) uses mtn features that did not exist in 0.14:
3. The attr commands. It is necessary to translate these to manipulations of .mt-attr, which is how attributes used to be done. (Note that schema_migration_with_rosterify does not attempt to test attribute migration - which is worrisome, as that is a major part of the roster transition.)
4. The --message-file option is not present, and putting the message on the command line does not appear to work.
5. It is not clear whether the --date option works. It is accepted for commit, but not propagate.
6. monotone 0.14 wants [pubkey] and [privkey] packets instead of [keypair] packets. I do not know how to convert the latter to the former. I snarfed the key out of 0.14's testsuite.at instead, but I'm not sure it's the same one.
7. There might be an outright bug in the code to generate test databases: testfile2 is added, then we revert to a revision in which it didn't exist, modify it, and check in another revision without adding it again. Is that intentional?
8. If you bull your way past all of that, you get a database, which you can dump with the old version, reload with the new one, and run through db migrate. Then you get this from db changesetify:

mtn: rebuilding revision graph from manifest certs
mtn: certs in | certs out | nodes | revs out
mtn:       28 |         0 |     5 |        0
mtn: scanning for bogus merge edges
mtn: fatal: std::logic_error: ../S-vanilla/revision.cc:861: invariant 'fetching nonexistent entry from node_to_old_rev' violated

I will make the debugging log and/or the database dump available if anyone asks.

patches for 0.14

#!cplusplus
============================================================
--- cryptopp/integer.cpp        f2a0e049b9aef571c5807afd972a77f377482d8f
+++ cryptopp/integer.cpp        e2cf6746ad5ce51d0bd2406ec07f9bcda36f5aa9
@@ -1473,7 +1473,7 @@ void <span class="createlink">PentiumOptimized</span>::Square4(word* Y,

                :
                : "D" (Y), "S" (X)
-               : "eax",  "ecx", "edx", "ebp",   "memory"
+               : "eax",  "ecx", "edx", "memory"
        );
 }

============================================================
--- cryptopp/pubkey.h   e3fbc0074a9c736ed86f4e4003de49f2bdf89c96
+++ cryptopp/pubkey.h   0328c2a5276ff0173a6eb0a44d5493fd943d2b87
@@ -38,6 +38,8 @@
 #include "fips140.h"
 #include "argnames.h"
 #include "modarith.h"
+#include "asn.h"
+
 #include <memory>

 // VC60 workaround: this macro is defined in shlobj.h and conflicts with a template parameter used in this file
@@ -745,8 +747,6 @@ void DL_<span class="createlink">PublicKey</span><T>::<span class="createlink">AssignFrom</span>(const N
        }
 }

-class OID;
-
 //! .
 template <class PK, class GP>
 class DL_<span class="createlink">KeyImpl</span> : public PK
============================================================
--- merkle_tree.cc      565e0f4242011220ff3b20574cff68d74552ee2a
+++ merkle_tree.cc      2abde1a4a10709bec5ad40e325ce4016b1fcd0e1
@@ -144,7 +144,7 @@ merkle_node::extended_prefix(size_t slot

 void
 merkle_node::extended_prefix(size_t slot,
-                            dynamic_bitset<char> & extended) const
+                            dynamic_bitset<unsigned char> & extended) const
 {
   // remember, in a dynamic_bitset, bit size()-1 is most significant
   check_invariants();
@@ -158,7 +158,7 @@ merkle_node::extended_raw_prefix(size_t
 merkle_node::extended_raw_prefix(size_t slot,
                                 prefix & extended) const
 {
-  dynamic_bitset<char> ext;
+  dynamic_bitset<unsigned char> ext;
   extended_prefix(slot, ext);
   ostringstream oss;
   to_block_range(ext, ostream_iterator<char>(oss));
@@ -363,7 +363,7 @@ pick_slot_and_prefix_for_value(id const
 pick_slot_and_prefix_for_value(id const & val,
                               size_t level,
                               size_t & slotnum,
-                              dynamic_bitset<char> & pref)
+                              dynamic_bitset<unsigned char> & pref)
 {
   pref.resize(val().size() * 8);
   from_block_range(val().begin(), val().end(), pref);
@@ -401,7 +401,7 @@ insert_into_merkle_tree(app_state & app,
   encode_hexenc(leaf, hleaf);

   size_t slotnum;
-  dynamic_bitset<char> pref;
+  dynamic_bitset<unsigned char> pref;
   pick_slot_and_prefix_for_value(leaf, level, slotnum, pref);

   ostringstream oss;
============================================================
--- merkle_tree.hh      8adb43063411673b9fd8ca07410e53a6e2d308f3
+++ merkle_tree.hh      635f951bdc8a6d045c8b063afd228508944f7513
@@ -55,9 +55,9 @@ struct merkle_node
 struct merkle_node
 {
   size_t level;
-  boost::dynamic_bitset<char> pref;
+  boost::dynamic_bitset<unsigned char> pref;
   size_t total_num_leaves;
-  boost::dynamic_bitset<char> bitmap;
+  boost::dynamic_bitset<unsigned char> bitmap;
   std::vector<id> slots;
   netcmd_item_type type;

@@ -74,7 +74,7 @@ struct merkle_node
   void set_raw_slot(size_t slot, id const & val);
   void set_hex_slot(size_t slot, hexenc<id> const & val);

-  void extended_prefix(size_t slot, boost::dynamic_bitset<char> & extended) const;
+  void extended_prefix(size_t slot, boost::dynamic_bitset<unsigned char> & extended) const;
   void extended_raw_prefix(size_t slot, prefix & extended) const;
   void extended_hex_prefix(size_t slot, hexenc<prefix> & extended) const;

@@ -106,7 +106,7 @@ void pick_slot_and_prefix_for_value(id c
                     merkle_node const & node);

 void pick_slot_and_prefix_for_value(id const & val, size_t level,
-                                   size_t & slotnum, boost::dynamic_bitset<char> & pref);
+                                   size_t & slotnum, boost::dynamic_bitset<unsigned char> & pref);

 // this inserts a leaf into the appropriate position in a merkle
 // tree, writing it to the db and updating any other nodes in the