[CF 5767] v1 - Fix violation of principle that plan trees are read-only

This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5767

The branch will be overwritten each time a new patch version is posted to
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on the master branch.

Patch(es): https://www.postgresql.org/message-id/1288373.1747843558@sss.pgh.pa.us
Author(s): Tom Lane

Author: Commitfest Bot

src/backend/commands/explain.c

@@ -1232,6 +1232,10 @@ ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
 			if (((ModifyTable *) plan)->exclRelRTI)
 				*rels_used = bms_add_member(*rels_used,
 											((ModifyTable *) plan)->exclRelRTI);
+			/* Ensure Vars used in RETURNING will have refnames */
+			if (plan->targetlist)
+				*rels_used = bms_add_member(*rels_used,
+											linitial_int(((ModifyTable *) plan)->resultRelations));
 			break;
 		case T_Append:
 			*rels_used = bms_add_members(*rels_used,

src/backend/executor/nodeModifyTable.c

@@ -4830,12 +4830,11 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		ExprContext *econtext;
 
 		/*
-		 * Initialize result tuple slot and assign its rowtype using the first
-		 * RETURNING list.  We assume the rest will look the same.
+		 * Initialize result tuple slot and assign its rowtype using the plan
+		 * node's declared targetlist, which the planner set up to be the same
+		 * as the first (before runtime pruning) RETURNING list.  We assume
+		 * all the result rels will produce compatible output.
 		 */
-		mtstate->ps.plan->targetlist = (List *) linitial(returningLists);
-
-		/* Set up a slot for the output of the RETURNING projection(s) */
 		ExecInitResultTupleSlotTL(&mtstate->ps, &TTSOpsVirtual);
 		slot = mtstate->ps.ps_ResultTupleSlot;
 
@@ -4865,7 +4864,6 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		 * We still must construct a dummy result tuple type, because InitPlan
 		 * expects one (maybe should change that?).
 		 */
-		mtstate->ps.plan->targetlist = NIL;
 		ExecInitResultTypeTL(&mtstate->ps);
 
 		mtstate->ps.ps_ExprContext = NULL;

src/backend/optimizer/plan/setrefs.c

@@ -1097,9 +1097,10 @@ set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
 
 					/*
 					 * Set up the visible plan targetlist as being the same as
-					 * the first RETURNING list. This is for the use of
-					 * EXPLAIN; the executor won't pay any attention to the
-					 * targetlist.  We postpone this step until here so that
+					 * the first RETURNING list.  This is mostly for the use
+					 * of EXPLAIN; the executor won't execute that targetlist,
+					 * although it does use it to prepare the node's result
+					 * tuple slot.  We postpone this step until here so that
 					 * we don't have to do set_returning_clause_references()
 					 * twice on identical targetlists.
 					 */

src/test/regress/expected/partition_prune.out

@@ -4553,45 +4553,50 @@ create view part_abc_view as select * from part_abc where b <> 'a' with check op
 prepare update_part_abc_view as update part_abc_view set b = $2 where a = $1 returning *;
 -- Only the unpruned partition should be shown in the list of relations to be
 -- updated
-explain (costs off) execute update_part_abc_view (1, 'd');
-                      QUERY PLAN                       
--------------------------------------------------------
- Update on part_abc
-   Update on part_abc_1
+explain (verbose, costs off) execute update_part_abc_view (1, 'd');
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
+ Update on public.part_abc
+   Output: part_abc_1.a, part_abc_1.b, part_abc_1.c
+   Update on public.part_abc_1
    ->  Append
          Subplans Removed: 1
-         ->  Seq Scan on part_abc_1
-               Filter: ((b <> 'a'::text) AND (a = $1))
-(6 rows)
+         ->  Seq Scan on public.part_abc_1
+               Output: $2, part_abc_1.tableoid, part_abc_1.ctid
+               Filter: ((part_abc_1.b <> 'a'::text) AND (part_abc_1.a = $1))
+(8 rows)
 
 execute update_part_abc_view (1, 'd');
  a | b | c 
 ---+---+---
  1 | d | t
 (1 row)
 
-explain (costs off) execute update_part_abc_view (2, 'a');
-                      QUERY PLAN                       
--------------------------------------------------------
- Update on part_abc
-   Update on part_abc_2 part_abc_1
+explain (verbose, costs off) execute update_part_abc_view (2, 'a');
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
+ Update on public.part_abc
+   Output: part_abc_1.a, part_abc_1.b, part_abc_1.c
+   Update on public.part_abc_2
    ->  Append
          Subplans Removed: 1
-         ->  Seq Scan on part_abc_2 part_abc_1
-               Filter: ((b <> 'a'::text) AND (a = $1))
-(6 rows)
+         ->  Seq Scan on public.part_abc_2
+               Output: $2, part_abc_2.tableoid, part_abc_2.ctid
+               Filter: ((part_abc_2.b <> 'a'::text) AND (part_abc_2.a = $1))
+(8 rows)
 
 execute update_part_abc_view (2, 'a');
 ERROR:  new row violates check option for view "part_abc_view"
 DETAIL:  Failing row contains (2, a, t).
 -- All pruned.
-explain (costs off) execute update_part_abc_view (3, 'a');
-         QUERY PLAN          
------------------------------
- Update on part_abc
+explain (verbose, costs off) execute update_part_abc_view (3, 'a');
+                     QUERY PLAN                     
+----------------------------------------------------
+ Update on public.part_abc
+   Output: part_abc_1.a, part_abc_1.b, part_abc_1.c
    ->  Append
          Subplans Removed: 2
-(3 rows)
+(4 rows)
 
 execute update_part_abc_view (3, 'a');
  a | b | c 

src/test/regress/sql/partition_prune.sql

@@ -1371,12 +1371,12 @@ create view part_abc_view as select * from part_abc where b <> 'a' with check op
 prepare update_part_abc_view as update part_abc_view set b = $2 where a = $1 returning *;
 -- Only the unpruned partition should be shown in the list of relations to be
 -- updated
-explain (costs off) execute update_part_abc_view (1, 'd');
+explain (verbose, costs off) execute update_part_abc_view (1, 'd');
 execute update_part_abc_view (1, 'd');
-explain (costs off) execute update_part_abc_view (2, 'a');
+explain (verbose, costs off) execute update_part_abc_view (2, 'a');
 execute update_part_abc_view (2, 'a');
 -- All pruned.
-explain (costs off) execute update_part_abc_view (3, 'a');
+explain (verbose, costs off) execute update_part_abc_view (3, 'a');
 execute update_part_abc_view (3, 'a');
 deallocate update_part_abc_view;