Fix error code for referential action RESTRICT

According to the SQL standard, if the referential action RESTRICT is
triggered, it has its own error code.  We previously didn't use that,
we just used the error code for foreign key violation.  But RESTRICT
is not necessarily an actual foreign key violation.  The foreign key
might still be satisfied in theory afterwards, but the RESTRICT
setting prevents the action even then.  So it's a separate kind of
error condition.

Discussion: https://www.postgresql.org/message-id/ea5b2777-266a-46fa-852f-6fca6ec480ad@eisentraut.org

1 files changed, 27 insertions, 5 deletions

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 91792cb2a47..3185f48afa6 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -228,6 +228,7 @@ static bool ri_PerformCheck(const RI_ConstraintInfo *riinfo,
 							RI_QueryKey *qkey, SPIPlanPtr qplan,
 							Relation fk_rel, Relation pk_rel,
 							TupleTableSlot *oldslot, TupleTableSlot *newslot,
+							bool is_restrict,
 							bool detectNewRows, int expect_OK);
 static void ri_ExtractValues(Relation rel, TupleTableSlot *slot,
 							 const RI_ConstraintInfo *riinfo, bool rel_is_pk,
@@ -235,7 +236,7 @@ static void ri_ExtractValues(Relation rel, TupleTableSlot *slot,
 static void ri_ReportViolation(const RI_ConstraintInfo *riinfo,
 							   Relation pk_rel, Relation fk_rel,
 							   TupleTableSlot *violatorslot, TupleDesc tupdesc,
-							   int queryno, bool partgone) pg_attribute_noreturn();
+							   int queryno, bool is_restrict, bool partgone) pg_attribute_noreturn();
 
 
 /*
@@ -449,6 +450,7 @@ RI_FKey_check(TriggerData *trigdata)
 	ri_PerformCheck(riinfo, &qkey, qplan,
 					fk_rel, pk_rel,
 					NULL, newslot,
+					false,
 					pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE,
 					SPI_OK_SELECT);
 
@@ -613,6 +615,7 @@ ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
 	result = ri_PerformCheck(riinfo, &qkey, qplan,
 							 fk_rel, pk_rel,
 							 oldslot, NULL,
+							 false,
 							 true,	/* treat like update */
 							 SPI_OK_SELECT);
 
@@ -800,6 +803,7 @@ ri_restrict(TriggerData *trigdata, bool is_no_action)
 	ri_PerformCheck(riinfo, &qkey, qplan,
 					fk_rel, pk_rel,
 					oldslot, NULL,
+					!is_no_action,
 					true,		/* must detect new rows */
 					SPI_OK_SELECT);
 
@@ -901,6 +905,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
 	ri_PerformCheck(riinfo, &qkey, qplan,
 					fk_rel, pk_rel,
 					oldslot, NULL,
+					false,
 					true,		/* must detect new rows */
 					SPI_OK_DELETE);
 
@@ -1017,6 +1022,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 	ri_PerformCheck(riinfo, &qkey, qplan,
 					fk_rel, pk_rel,
 					oldslot, newslot,
+					false,
 					true,		/* must detect new rows */
 					SPI_OK_UPDATE);
 
@@ -1244,6 +1250,7 @@ ri_set(TriggerData *trigdata, bool is_set_null, int tgkind)
 	ri_PerformCheck(riinfo, &qkey, qplan,
 					fk_rel, pk_rel,
 					oldslot, NULL,
+					false,
 					true,		/* must detect new rows */
 					SPI_OK_UPDATE);
 
@@ -1690,7 +1697,7 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 		ri_ReportViolation(&fake_riinfo,
 						   pk_rel, fk_rel,
 						   slot, tupdesc,
-						   RI_PLAN_CHECK_LOOKUPPK, false);
+						   RI_PLAN_CHECK_LOOKUPPK, false, false);
 
 		ExecDropSingleTupleTableSlot(slot);
 	}
@@ -1906,7 +1913,7 @@ RI_PartitionRemove_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 			fake_riinfo.pk_attnums[i] = i + 1;
 
 		ri_ReportViolation(&fake_riinfo, pk_rel, fk_rel,
-						   slot, tupdesc, 0, true);
+						   slot, tupdesc, 0, false, true);
 	}
 
 	if (SPI_finish() != SPI_OK_FINISH)
@@ -2387,6 +2394,7 @@ ri_PerformCheck(const RI_ConstraintInfo *riinfo,
 				RI_QueryKey *qkey, SPIPlanPtr qplan,
 				Relation fk_rel, Relation pk_rel,
 				TupleTableSlot *oldslot, TupleTableSlot *newslot,
+				bool is_restrict,
 				bool detectNewRows, int expect_OK)
 {
 	Relation	query_rel,
@@ -2511,7 +2519,7 @@ ri_PerformCheck(const RI_ConstraintInfo *riinfo,
 						   pk_rel, fk_rel,
 						   newslot ? newslot : oldslot,
 						   NULL,
-						   qkey->constr_queryno, false);
+						   qkey->constr_queryno, is_restrict, false);
 
 	return SPI_processed != 0;
 }
@@ -2552,7 +2560,7 @@ static void
 ri_ReportViolation(const RI_ConstraintInfo *riinfo,
 				   Relation pk_rel, Relation fk_rel,
 				   TupleTableSlot *violatorslot, TupleDesc tupdesc,
-				   int queryno, bool partgone)
+				   int queryno, bool is_restrict, bool partgone)
 {
 	StringInfoData key_names;
 	StringInfoData key_values;
@@ -2682,6 +2690,20 @@ ri_ReportViolation(const RI_ConstraintInfo *riinfo,
 				 errdetail("Key is not present in table \"%s\".",
 						   RelationGetRelationName(pk_rel)),
 				 errtableconstraint(fk_rel, NameStr(riinfo->conname))));
+	else if (is_restrict)
+		ereport(ERROR,
+				(errcode(ERRCODE_RESTRICT_VIOLATION),
+				 errmsg("update or delete on table \"%s\" violates RESTRICT setting of foreign key constraint \"%s\" on table \"%s\"",
+						RelationGetRelationName(pk_rel),
+						NameStr(riinfo->conname),
+						RelationGetRelationName(fk_rel)),
+				 has_perm ?
+				 errdetail("Key (%s)=(%s) is referenced from table \"%s\".",
+						   key_names.data, key_values.data,
+						   RelationGetRelationName(fk_rel)) :
+				 errdetail("Key is referenced from table \"%s\".",
+						   RelationGetRelationName(fk_rel)),
+				 errtableconstraint(fk_rel, NameStr(riinfo->conname))));
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_FOREIGN_KEY_VIOLATION),