Include column name in build_attrmap_by_position's error reports.

Formerly we only provided the column number, but it's frequently
more useful to mention the column name.  The input tupdesc often
doesn't have useful column names, but the output tupdesc usually
contains user-supplied names, so report that one.

Author: Marcos Pegoraro <marcos@f10.com.br>
Co-authored-by: jian he <jian.universality@gmail.com>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Co-authored-by: Erik Wienhold <ewie@ewie.name>
Reviewed-by: Vladlen Popolitov <v.popolitov@postgrespro.ru>
Discussion: https://postgr.es/m/CAB-JLwanky28gjAMdnMh1CjyO1b2zLdr6UOA1-oY9G7PVL9KKQ@mail.gmail.com

Author: 3 people

src/backend/access/common/attmap.c

@@ -96,33 +96,31 @@ build_attrmap_by_position(TupleDesc indesc,
 	same = true;
 	for (i = 0; i < n; i++)
 	{
-		Form_pg_attribute att = TupleDescAttr(outdesc, i);
-		Oid			atttypid;
-		int32		atttypmod;
+		Form_pg_attribute outatt = TupleDescAttr(outdesc, i);
 
-		if (att->attisdropped)
+		if (outatt->attisdropped)
 			continue;			/* attrMap->attnums[i] is already 0 */
 		noutcols++;
-		atttypid = att->atttypid;
-		atttypmod = att->atttypmod;
 		for (; j < indesc->natts; j++)
 		{
-			att = TupleDescAttr(indesc, j);
-			if (att->attisdropped)
+			Form_pg_attribute inatt = TupleDescAttr(indesc, j);
+
+			if (inatt->attisdropped)
 				continue;
 			nincols++;
 
 			/* Found matching column, now check type */
-			if (atttypid != att->atttypid ||
-				(atttypmod != att->atttypmod && atttypmod >= 0))
+			if (outatt->atttypid != inatt->atttypid ||
+				(outatt->atttypmod != inatt->atttypmod && outatt->atttypmod >= 0))
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg_internal("%s", _(msg)),
-						 errdetail("Returned type %s does not match expected type %s in column %d.",
-								   format_type_with_typemod(att->atttypid,
-															att->atttypmod),
-								   format_type_with_typemod(atttypid,
-															atttypmod),
+						 errdetail("Returned type %s does not match expected type %s in column \"%s\" (position %d).",
+								   format_type_with_typemod(inatt->atttypid,
+															inatt->atttypmod),
+								   format_type_with_typemod(outatt->atttypid,
+															outatt->atttypmod),
+								   NameStr(outatt->attname),
 								   noutcols)));
 			attrMap->attnums[i] = (AttrNumber) (j + 1);
 			j++;

src/pl/plpgsql/src/expected/plpgsql_record.out

@@ -28,7 +28,7 @@ create or replace function retc(int) returns two_int8s language plpgsql as
 $$ begin return row($1,1); end $$;
 select retc(42);
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type integer does not match expected type bigint in column 1.
+DETAIL:  Returned type integer does not match expected type bigint in column "q1" (position 1).
 CONTEXT:  PL/pgSQL function retc(integer) while casting return value to function's return type
 -- nor extra columns
 create or replace function retc(int) returns two_int8s language plpgsql as
@@ -50,7 +50,7 @@ create or replace function retc(int) returns two_int8s language plpgsql as
 $$ declare r record; begin r := row($1,1); return r; end $$;
 select retc(42);
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type integer does not match expected type bigint in column 1.
+DETAIL:  Returned type integer does not match expected type bigint in column "q1" (position 1).
 CONTEXT:  PL/pgSQL function retc(integer) while casting return value to function's return type
 create or replace function retc(int) returns two_int8s language plpgsql as
 $$ declare r record; begin r := row($1::int8, 1::int8, 42); return r; end $$;
@@ -386,7 +386,7 @@ DETAIL:  Number of returned columns (2) does not match expected column count (3)
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 select * from returnsrecord(42) as r(x int, y bigint);  -- fail
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type integer does not match expected type bigint in column 2.
+DETAIL:  Returned type integer does not match expected type bigint in column "y" (position 2).
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 -- same with an intermediate record variable
 create or replace function returnsrecord(int) returns record language plpgsql as
@@ -409,7 +409,7 @@ DETAIL:  Number of returned columns (2) does not match expected column count (3)
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 select * from returnsrecord(42) as r(x int, y bigint);  -- fail
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type integer does not match expected type bigint in column 2.
+DETAIL:  Returned type integer does not match expected type bigint in column "y" (position 2).
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 -- should work the same with a missing column in the actual result value
 create table has_hole(f1 int, f2 int, f3 int);
@@ -434,7 +434,7 @@ DETAIL:  Number of returned columns (2) does not match expected column count (3)
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 select * from returnsrecord(42) as r(x int, y bigint);  -- fail
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type integer does not match expected type bigint in column 2.
+DETAIL:  Returned type integer does not match expected type bigint in column "y" (position 2).
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 -- same with an intermediate record variable
 create or replace function returnsrecord(int) returns record language plpgsql as
@@ -457,7 +457,7 @@ DETAIL:  Number of returned columns (2) does not match expected column count (3)
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 select * from returnsrecord(42) as r(x int, y bigint);  -- fail
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type integer does not match expected type bigint in column 2.
+DETAIL:  Returned type integer does not match expected type bigint in column "y" (position 2).
 CONTEXT:  PL/pgSQL function returnsrecord(integer) while casting return value to function's return type
 -- check access to a field of an argument declared "record"
 create function getf1(x record) returns int language plpgsql as
@@ -545,6 +545,7 @@ begin
   return next h;
   return next row(5,6);
   return next row(7,8)::has_hole;
+  return query select 9, 10;
 end$$;
 select returnssetofholes();
  returnssetofholes 
@@ -554,7 +555,8 @@ select returnssetofholes();
  (3,4)
  (5,6)
  (7,8)
-(5 rows)
+ (9,10)
+(6 rows)
 
 create or replace function returnssetofholes() returns setof has_hole language plpgsql as
 $$
@@ -575,6 +577,16 @@ select returnssetofholes();
 ERROR:  returned record type does not match expected record type
 DETAIL:  Number of returned columns (3) does not match expected column count (2).
 CONTEXT:  PL/pgSQL function returnssetofholes() line 3 at RETURN NEXT
+create or replace function returnssetofholes() returns setof has_hole language plpgsql as
+$$
+begin
+  return query select 1, 2.0;  -- fails
+end$$;
+select returnssetofholes();
+ERROR:  structure of query does not match function result type
+DETAIL:  Returned type numeric does not match expected type integer in column "f3" (position 2).
+CONTEXT:  SQL statement "select 1, 2.0"
+PL/pgSQL function returnssetofholes() line 3 at RETURN QUERY
 -- check behavior with changes of a named rowtype
 create table mutable(f1 int, f2 text);
 create function sillyaddone(int) returns int language plpgsql as

src/pl/plpgsql/src/sql/plpgsql_record.sql

@@ -338,6 +338,7 @@ begin
   return next h;
   return next row(5,6);
   return next row(7,8)::has_hole;
+  return query select 9, 10;
 end$$;
 select returnssetofholes();
 
@@ -356,6 +357,13 @@ begin
 end$$;
 select returnssetofholes();
 
+create or replace function returnssetofholes() returns setof has_hole language plpgsql as
+$$
+begin
+  return query select 1, 2.0;  -- fails
+end$$;
+select returnssetofholes();
+
 -- check behavior with changes of a named rowtype
 create table mutable(f1 int, f2 text);
 

src/test/regress/expected/plpgsql.out

@@ -3779,7 +3779,7 @@ end;
 $$ language plpgsql;
 select compos();
 ERROR:  returned record type does not match expected record type
-DETAIL:  Returned type unknown does not match expected type character varying in column 2.
+DETAIL:  Returned type unknown does not match expected type character varying in column "y" (position 2).
 CONTEXT:  PL/pgSQL function compos() while casting return value to function's return type
 -- ... but this does
 create or replace function compos() returns compostype as $$