Redis [BUG] failing sort of sorted-set changes the zset?

Describe the bug

Running the following test on redis 7.4+ fails. The response from the server is [b"A"].

However, if you remove the sort command, the test passes.

def test_zrangebyscore_negative_start_after_sort(r: redis.Redis):
    r.zadd("A", {"A": 0.0})
    r.zadd("B", {"A": 0.0})
    with pytest.raises(redis.ResponseError):
        r.sort("B")
    assert r.zrangebyscore("B", 0.0, 0.0, start=-1, num=1) == [] # Here

On redis 6.2 the test passes. See here more details which versions it fails/passes

Comment From: sundb

@cunla sort might change the encoding of sortset, in this case, this sortset was converted from listpack to skiplist.

    /* Destructively convert encoded sorted sets for SORT. */
    if (sortval->type == OBJ_ZSET)
        zsetConvert(sortval, OBJ_ENCODING_SKIPLIST);

seems that https://github.com/redis/redis/pull/12450 brought a bug.

flushdb
zadd a 0.0 A
sort a <- converted to skiplist
# zrangebyscore would return empty before #12450, but now returns the last value.
zrangebyscore a 0.0 0.0 limit -1 1

@cunla do you want to fix it? FYI @oranagra

Comment From: cunla

I can give it a shot

Comment From: yzc-yzc

Hello@cunla ! I've noticed this issue has been stalled for a while. I'm interested in it. Could I pick it up?