[Monotone-devel] [BUG] merge_into_workspace fails on second merge attempt

[Ralf S. Engelschall]

With the appended tiny test repository (which contains just two branches
"test" and "test.2"), when I perform a initial "merge_into_workspace"
from test.2 to test everything works fine. But if I repeat this once
"test.2" was already merged to "test" (e.g. even with propagate) the
"merge_into_workspace" aborts because an invariant in roster.cc is
not fulfilled (the ~/prj/monotone/src/mtn is the latest Monotone from
h:n.v.m as of today and the "diffutils" is just used for full batch
operation):

| $ export MTN_MERGE=diffutils; export MTN_MERGE_DIFFUTILS=partial; \
|   cp test.db.bak test.db; ~/prj/monotone/src/mtn --db=/tmp/test.db \
|   propagate test.2 test; (rm -rf test; ~/prj/monotone/src/mtn \
|   --db=/tmp/test.dbco -b test test; cd test; ~/prj/monotone/src/mtn \
|   merge_into_workspace b:test.2)
| mtn: propagating test.2 -> test
| mtn: [source] fa031b9e25421817806d8388559c9fb430128913
| mtn: [target] e363b9f348f4e1da9849c1e8b9ed12bbb893f505
| mtn: help required for 3-way merge
| mtn: [ancestor] test
| mtn: [    left] test
| mtn: [   right] test
| mtn: [  merged] test
| executing external 3-way merge command
| performing 3-way merge, adding conflict markers
| mtn: [merged] df773bab0a43d69c1b7f8db06538f3c1cab108f8
| mtn: expanding selection 'b:test.2'
| mtn: expanded to 'fa031b9e25421817806d8388559c9fb430128913'
| mtn: fatal: std::logic_error: roster.cc:1810: invariant 
'I(right_uncommon_ancestors.find(right_rid) != right_uncommon_ancestors.end())' 
violated
| mtn: this is almost certainly a bug in monotone.
| mtn: please send this error message, the output of 'mtn version --full',
| mtn: and a description of what you were doing to address@hidden
| mtn: wrote debugging log to /tmp/test/_MTN/debug
| mtn: if reporting a bug, please include this file

Can anybody with a deeper understanding of the code base help?

                                       Ralf S. Engelschall
                                       address@hidden
                                       www.engelschall.com

test.db.bak
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