Re: TupleDescAttr bounds checks

Hello Robert,

24.03.2026 12:45, Robert Haas wrote:
> On Sun, Mar 22, 2026 at 11:54 PM Tom Lane<tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Anyway, you should get this fix pushed.
> Done, and I'll plan to commit the other patches later today.

I've found a way to trigger the Assert added in c98ad086a:
CREATE TABLE t(i int);
COPY t FROM stdin WHERE tableoid > 0;
server closed the connection unexpectedly

(gdb) bt
#0  __pthread_kill_implementation (no_tid=0, signo=6, threadid=<optimized out>) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=<optimized out>) at ./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=<optimized out>, signo=signo(at)entry=6) at ./nptl/pthread_kill.c:89
#3  0x00007066d0e4527e in __GI_raise (sig=sig(at)entry=6) at ../sysdeps/posix/raise.c:26
#4  0x00007066d0e288ff in __GI_abort () at ./stdlib/abort.c:79
#5  0x0000609680cc7fcf in ExceptionalCondition (
    conditionName=conditionName(at)entry=0x609680d2c104 "i >= 0 && i < tupdesc->natts",
    fileName=fileName(at)entry=0x609680d84568 "../../../src/include/access/tupdesc.h", lineNumber=lineNumber(at)entry=182)
    at assert.c:65
#6  0x00006096808c8f68 in TupleDescAttr (tupdesc=<optimized out>, i=<optimized out>)
    at ../../../src/include/access/tupdesc.h:182
#7  TupleDescAttr (i=<optimized out>, tupdesc=<optimized out>) at ../../../src/include/access/tupdesc.h:178
#8  DoCopy (pstate=0x6096a749dc90, stmt=0x6096a74ca120, stmt_location=0, stmt_len=40, processed=0x7ffd3b09b450) at
copy.c:180
#9  0x0000609680b6b82a in standard_ProcessUtility (pstmt=0x6096a74ca1f0,
    queryString=0x6096a74c9520 "COPY t FROM stdin WHERE tableoid > 0;", readOnlyTree=<optimized out>,
    context=PROCESS_UTILITY_TOPLEVEL, params=0x0, queryEnv=0x0, dest=0x6096a74ca5b0, qc=0x7ffd3b09b6f0) at utility.c:743
#10 0x0000609680b6990c in PortalRunUtility (portal=portal(at)entry=0x6096a756a070, pstmt=pstmt(at)entry=0x6096a74ca1f0,
    isTopLevel=isTopLevel(at)entry=true, setHoldSnapshot=setHoldSnapshot(at)entry=false, dest=dest(at)entry=0x6096a74ca5b0,
    qc=qc(at)entry=0x7ffd3b09b6f0) at pquery.c:1148
...

Best regards,
Alexander