assertion in 9.4 with wal_level=logical

With master/9.4 from today (52e757420fa98a76015c2c88432db94269f3e8f4)

I am getting an assertion when doing a truncate via SPI when I have
wal_level=logical.

Stack trace is below.

I am just replicating a table with normal slony (2.2) I don't need to
establish any replication slots to get this.

(gdb) where
#0 0x00007fc9b4f58295 in __GI_raise (sig=sig(at)entry=6)
at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007fc9b4f5b438 in __GI_abort () at abort.c:90
#2 0x00000000007a10f7 in ExceptionalCondition (
conditionName=conditionName(at)entry=0x955d90 "!(CritSectionCount == 0
|| (CurrentMemoryContext) == ErrorContext || (MyAuxProcType ==
CheckpointerProcess))",
errorType=errorType(at)entry=0x7da7b0 "FailedAssertion",
fileName=fileName(at)entry=0x955a2e "mcxt.c",
lineNumber=lineNumber(at)entry=670)
at assert.c:54
#3 0x00000000007c3090 in palloc (size=16) at mcxt.c:670
#4 0x00000000004dd83f in mXactCacheGetById (members=0x7fff679a3d18,
multi=58)
at multixact.c:1411
#5 GetMultiXactIdMembers (multi=58, members=members(at)entry=0x7fff679a3d18,
allow_old=allow_old(at)entry=0 '\000') at multixact.c:1080
#6 0x000000000049e43f in MultiXactIdGetUpdateXid (xmax=<optimized out>,
t_infomask=<optimized out>) at heapam.c:6042
#7 0x00000000004a1ccc in HeapTupleGetUpdateXid (tuple=<optimized out>)
at heapam.c:6083
#8 0x00000000007cf7d9 in HeapTupleHeaderGetCmax
(tup=tup(at)entry=0x7fc9ac838e38)
at combocid.c:122
#9 0x000000000049eb98 in log_heap_new_cid (
relation=relation(at)entry=0x7fc9b5a67dc0, tup=tup(at)entry=0x7fff679a3ea0)
at heapam.c:7047
#10 0x00000000004a48a5 in heap_update
(relation=relation(at)entry=0x7fc9b5a67dc0,
otid=otid(at)entry=0x2678c6c, newtup=newtup(at)entry=0x2678c68, cid=26,
crosscheck=crosscheck(at)entry=0x0, wait=wait(at)entry=1 '\001',
hufd=hufd(at)entry=0x7fff679a4080, lockmode=lockmode(at)entry=0x7fff679a407c)
at heapam.c:3734
#11 0x00000000004a5842 in simple_heap_update (
relation=relation(at)entry=0x7fc9b5a67dc0, otid=otid(at)entry=0x2678c6c,
tup=tup(at)entry=0x2678c68) at heapam.c:4010
#12 0x0000000000797cf7 in RelationSetNewRelfilenode (
relation=relation(at)entry=0x7fc9ab270b68, freezeXid=19459,
minmulti=minmulti(at)entry=58) at relcache.c:2956
#13 0x000000000059ddde in ExecuteTruncate (stmt=0x3a, stmt(at)entry=0x2678a58)
at tablecmds.c:1187
#14 0x00000000006c3870 in standard_ProcessUtility (parsetree=0x2678a58,
queryString=<optimized out>, context=<optimized out>, params=0x0,
dest=<optimized out>, completionTag=<optimized out>) at utility.c:515
#15 0x00000000005e79d9 in _SPI_execute_plan
(plan=plan(at)entry=0x7fff679a4320,
paramLI=paramLI(at)entry=0x0, snapshot=snapshot(at)entry=0x0,
crosscheck_snapshot=crosscheck_snapshot(at)entry=0x0,
read_only=read_only(at)entry=0 '\000',
fire_triggers=fire_triggers(at)entry=1 '\001', tcount=tcount(at)entry=0)
at spi.c:2171
#16 0x00000000005e83c1 in SPI_execute (
#16 0x00000000005e83c1 in SPI_execute (
---Type <return> to continue, or q <return> to quit---
src=src(at)entry=0x25bde90 "truncate only \"disorder\".\"do_restock\"",
read_only=0 '\000', tcount=tcount(at)entry=0) at spi.c:386