Extract new error message fields in cdbdisp_get_PQerror()

Postgres 991f3e5a introduce new error
message fields, but cdbdisp_get_PQerror() did not extract these newly
added message field. These fields client cannot see from libpq.

This fixes https://github.com/greenplum-db/gpdb/issues/7934.
Co-authored-by: NAshwin Agrawal <aashwin@vmware.com>
Reviewed-by: NHeikki Linnakangas <hlinnaka@iki.fi>

src/backend/cdb/dispatcher/cdbdispatchresult.c

@@ -580,6 +580,28 @@ cdbdisp_get_PQerror(PGresult *pgresult)
 	if (fld)
 		errcontext("%s", fld);
 
+	fld = PQresultErrorField(pgresult, PG_DIAG_SCHEMA_NAME);
+	if (fld)
+		err_generic_string(PG_DIAG_SCHEMA_NAME, fld);
+
+	fld = PQresultErrorField(pgresult, PG_DIAG_TABLE_NAME);
+	if (fld)
+		err_generic_string(PG_DIAG_TABLE_NAME, fld);
+
+	fld = PQresultErrorField(pgresult, PG_DIAG_COLUMN_NAME);
+	if (fld)
+		err_generic_string(PG_DIAG_COLUMN_NAME, fld);
+
+	fld = PQresultErrorField(pgresult, PG_DIAG_DATATYPE_NAME);
+	if (fld)
+		err_generic_string(PG_DIAG_DATATYPE_NAME, fld);
+
+	fld = PQresultErrorField(pgresult, PG_DIAG_CONSTRAINT_NAME);
+	if (fld)
+		err_generic_string(PG_DIAG_CONSTRAINT_NAME, fld);
+
+	Assert(TopTransactionContext);
+
 	oldcontext = MemoryContextSwitchTo(TopTransactionContext);
 	ErrorData *edata = errfinish_and_return(filename, lineno, funcname);
 	MemoryContextSwitchTo(oldcontext);

src/test/regress/expected/gp_constraints.out

@@ -7,6 +7,10 @@
 -- error becomes time-sensitive and less predictable.
 -- To preserve coverage, we test those error details here (with greater care).
 --
+-- start_matchsubs
+-- m/^LOCATION:.*:\d+/
+-- s/:\d+/:/
+-- end_matchsubs
 CREATE SCHEMA gpdb_insert;
 SET search_path TO gpdb_insert;
 --
@@ -47,6 +51,16 @@ INSERT INTO tmp VALUES (1, 'three');
 INSERT INTO PRIMARY_TBL SELECT * FROM tmp;
 ERROR:  duplicate key value violates unique constraint "primary_tbl_pkey"
 DETAIL:  Key (i)=(1) already exists.
+-- database object names as separate fields in error messages can be shown when VERBOSITY set to verbose
+\set VERBOSITY verbose
+INSERT INTO PRIMARY_TBL SELECT * FROM tmp;
+ERROR:  23505: duplicate key value violates unique constraint "primary_tbl_pkey"
+DETAIL:  Key (i)=(1) already exists.
+SCHEMA NAME:  gpdb_insert
+TABLE NAME:  primary_tbl
+CONSTRAINT NAME:  primary_tbl_pkey
+LOCATION:  _bt_check_unique, nbtinsert.c:500
+\set VERBOSITY default
 SELECT '' AS four, * FROM PRIMARY_TBL;
  four | i |  t  
 ------+---+-----

src/test/regress/sql/gp_constraints.sql

@@ -7,6 +7,10 @@
 -- error becomes time-sensitive and less predictable.
 -- To preserve coverage, we test those error details here (with greater care).
 --
+-- start_matchsubs
+-- m/^LOCATION:.*:\d+/
+-- s/:\d+/:/
+-- end_matchsubs
 
 CREATE SCHEMA gpdb_insert;
 SET search_path TO gpdb_insert;
@@ -39,6 +43,10 @@ INSERT INTO PRIMARY_TBL VALUES (2, 'two');
 
 INSERT INTO tmp VALUES (1, 'three');
 INSERT INTO PRIMARY_TBL SELECT * FROM tmp;
+-- database object names as separate fields in error messages can be shown when VERBOSITY set to verbose
+\set VERBOSITY verbose
+INSERT INTO PRIMARY_TBL SELECT * FROM tmp;
+\set VERBOSITY default
 
 SELECT '' AS four, * FROM PRIMARY_TBL;