[sqlsmith] Failed assertion in create_gather_path

Hi,

sqlsmith found a query that triggers the following assertion in master
as of 039eb6e92f:

TRAP: FailedAssertion("!(subpath->parallel_safe)", File: "pathnode.c", Line: 1813)

Backtrace and recipe against the regression database below.

regards,
Andreas

#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007f25474cf42a in __GI_abort () at abort.c:89
#2  0x0000556c14b75bb3 in ExceptionalCondition (conditionName=conditionName@entry=0x556c14d16d68 "!(subpath->parallel_safe)",
    errorType=errorType@entry=0x556c14bc4dbd "FailedAssertion", fileName=fileName@entry=0x556c14d16d43 "pathnode.c",
    lineNumber=lineNumber@entry=1813) at assert.c:54
#3  0x0000556c149ca01d in create_gather_path (root=root@entry=0x556c16bfb7a0, rel=rel@entry=0x7f253e36f418, subpath=0x7f253e37d9d8,
    target=0x7f253e36f650, required_outer=required_outer@entry=0x0, rows=rows@entry=0x0) at pathnode.c:1813
#4  0x0000556c1498a3d7 in generate_gather_paths (root=root@entry=0x556c16bfb7a0, rel=rel@entry=0x7f253e36f418,
    override_rows=override_rows@entry=false) at allpaths.c:2564
#5  0x0000556c1498a7b0 in set_rel_pathlist (root=root@entry=0x556c16bfb7a0, rel=0x7f253e36f418, rti=rti@entry=2, rte=0x556c16bfb420)
    at allpaths.c:497
#6  0x0000556c1498b09d in set_base_rel_pathlists (root=<optimized out>) at allpaths.c:310
#7  make_one_rel (root=root@entry=0x556c16bfb7a0, joinlist=joinlist@entry=0x7f253e374450) at allpaths.c:180
#8  0x0000556c149abfac in query_planner (root=root@entry=0x556c16bfb7a0, tlist=tlist@entry=0x7f253e3eb4a0,
    qp_callback=qp_callback@entry=0x556c149acb90 <standard_qp_callback>, qp_extra=qp_extra@entry=0x7ffe8088a200) at planmain.c:259
#9  0x0000556c149b0be5 in grouping_planner (root=root@entry=0x556c16bfb7a0, inheritance_update=inheritance_update@entry=false,
    tuple_fraction=<optimized out>, tuple_fraction@entry=0) at planner.c:1914
#10 0x0000556c149b31a1 in subquery_planner (glob=glob@entry=0x556c16c234d0, parse=parse@entry=0x556c16bfaeb8,
    parent_root=parent_root@entry=0x0, hasRecursion=hasRecursion@entry=false, tuple_fraction=tuple_fraction@entry=0)
    at planner.c:984
#11 0x0000556c149b4356 in standard_planner (parse=0x556c16bfaeb8, cursorOptions=256, boundParams=<optimized out>) at planner.c:405
#12 0x0000556c14a680dd in pg_plan_query (querytree=0x556c16bfaeb8, cursorOptions=256, boundParams=0x0) at postgres.c:808
#13 0x0000556c14a681be in pg_plan_queries (querytrees=<optimized out>, cursorOptions=cursorOptions@entry=256,
    boundParams=boundParams@entry=0x0) at postgres.c:874
#14 0x0000556c14a686a9 in exec_simple_query (
    query_string=0x556c16b2b438 "...") at postgres.c:1049
#15 0x0000556c14a6a341 in PostgresMain (argc=<optimized out>, argv=argv@entry=0x556c16b56ad8, dbname=<optimized out>,
    username=<optimized out>) at postgres.c:4149
#16 0x0000556c1474eac4 in BackendRun (port=0x556c16b4c030) at postmaster.c:4409
#17 BackendStartup (port=0x556c16b4c030) at postmaster.c:4081
#18 ServerLoop () at postmaster.c:1754
#19 0x0000556c149ec017 in PostmasterMain (argc=3, argv=0x556c16b257d0) at postmaster.c:1362
#20 0x0000556c1475006d in main (argc=3, argv=0x556c16b257d0) at main.c:228

set min_parallel_table_scan_size to 0;
select
  66 as c0,
  ref_1.cid as c1,
    pg_catalog.min(
      cast((select timetzcol from public.brintest limit 1 offset 3)
	 as timetz)) over (partition by ref_1.name order by ref_1.name) as c2,
  ref_0.c as c3
from
  public.prt1_l as ref_0
    right join public.my_property_normal as ref_1
    on (ref_0.a <= ref_0.a)
where EXISTS (
  select
      ref_2.y as c0,
      ref_2.y as c1,
      sample_0.random as c2,
      ref_1.tel as c3,
      ref_0.a as c4,
      sample_0.random as c5,
      ref_2.y as c6,
      ref_2.x as c7,
      case when (true <> (select pg_catalog.bool_and(n) from testxmlschema.test2)
	      )
	  and (sample_0.seqno = (select int_four from public.test_type_diff2_c3 limit 1 offset 1)
	      ) then ref_2.y else ref_2.y end
	 as c8,
      sample_0.seqno as c9,
      ref_1.name as c10,
      ref_0.a as c11,
      (select nslots from public.hub limit 1 offset 2)
	 as c12,
      ref_1.name as c13
    from
      public.hash_name_heap as sample_0 tablesample system (8.2)
	left join public.tt6 as ref_2
	on ((((cast(null as tinterval) <= (select f1 from public.tinterval_tbl limit 1 offset 79)
		    )
		and (ref_2.y is not NULL))
	      or (((false)
		  and ((cast(null as tsquery) > (select keyword from public.test_tsquery limit 1 offset 34)
			)
		    or ((((select pg_catalog.jsonb_agg(sl_name) from public.shoelace_obsolete)
			     <@ cast(null as jsonb))
			or (EXISTS (
			  select
			      100 as c0,
			      ref_0.a as c1,
			      sample_0.seqno as c2,
			      ref_0.a as c3,
			      sample_0.seqno as c4,
			      ref_0.a as c5,
			      (select a from public.prt3_n limit 1 offset 30)
				 as c6,
			      ref_2.y as c7,
			      ref_1.cid as c8,
			      ref_2.y as c9
			    from
			      public.num_exp_mul as sample_1 tablesample system (7.1)
			    where true
			    limit 89)))
		      and (cast(null as _aclitem) @> cast(null as aclitem)))))
		and ((select timecol from public.brintest limit 1 offset 96)
		     > cast(null as "time"))))
	    and (cast(null as timestamptz) < cast(null as "timestamp")))
    where ((EXISTS (
	  select
	      sample_2.int_four as c0,
	      sample_0.seqno as c1,
	      43 as c2
	    from
	      public.test_type_diff2_c1 as sample_2 tablesample bernoulli (2.3)
	    where (sample_0.random ~~ ref_1.name)
	      and (ref_2.y <> ref_2.y)
	    limit 98))
	and (sample_0.random is NULL))
      and (cast(null as point) <@ (select b from public.quad_box_tbl limit 1 offset 5)
	  )
    limit 61);