Fix GetForeignKey*Triggers for self-referential FKs

alvherre · alvherre · commit 68b0da67794e · 2022-09-09T12:22:20.000+02:00
Because of inadequate filtering, the check triggers were confusing the search for action triggers in GetForeignKeyActionTriggers and vice-versa in GetForeignKeyCheckTriggers; this confusion results in seemingly random assertion failures, and can have real impact in non-asserting builds depending on catalog order. Change these functions so that they correctly ignore triggers that are not relevant to each side. To reduce the odds of further problems, do not break out of the searching loop in assertion builds. This break is likely to hide bugs; without it, we would have detected this bug immediately. This problem was introduced by f456634, so backpatch to 15 where that commit first appeared. Author: Amit Langote <amitlangote09@gmail.com> Discussion: https://postgr.es/m/20220908172029.sejft2ppckbo6oh5@awork3.anarazel.de Discussion: https://postgr.es/m/4104619.1662663056@sss.pgh.pa.us
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
@@ -10615,6 +10615,9 @@ GetForeignKeyActionTriggers(Relation trigrel,
 			continue;
 		if (trgform->tgrelid != confrelid)
 			continue;
+		/* Only ever look at "action" triggers on the PK side. */
+		if (RI_FKey_trigger_type(trgform->tgfoid) != RI_TRIGGER_PK)
+			continue;
 		if (TRIGGER_FOR_DELETE(trgform->tgtype))
 		{
 			Assert(*deleteTriggerOid == InvalidOid);
@@ -10625,8 +10628,11 @@ GetForeignKeyActionTriggers(Relation trigrel,
 			Assert(*updateTriggerOid == InvalidOid);
 			*updateTriggerOid = trgform->oid;
 		}
+#ifndef USE_ASSERT_CHECKING
+		/* In an assert-enabled build, continue looking to find duplicates */
 		if (OidIsValid(*deleteTriggerOid) && OidIsValid(*updateTriggerOid))
 			break;
+#endif
 	}
 
 	if (!OidIsValid(*deleteTriggerOid))
@@ -10670,6 +10676,9 @@ GetForeignKeyCheckTriggers(Relation trigrel,
 			continue;
 		if (trgform->tgrelid != conrelid)
 			continue;
+		/* Only ever look at "check" triggers on the FK side. */
+		if (RI_FKey_trigger_type(trgform->tgfoid) != RI_TRIGGER_FK)
+			continue;
 		if (TRIGGER_FOR_INSERT(trgform->tgtype))
 		{
 			Assert(*insertTriggerOid == InvalidOid);
@@ -10680,8 +10689,11 @@ GetForeignKeyCheckTriggers(Relation trigrel,
 			Assert(*updateTriggerOid == InvalidOid);
 			*updateTriggerOid = trgform->oid;
 		}
+#ifndef USE_ASSERT_CHECKING
+		/* In an assert-enabled build, continue looking to find duplicates. */
 		if (OidIsValid(*insertTriggerOid) && OidIsValid(*updateTriggerOid))
 			break;
+#endif
 	}
 
 	if (!OidIsValid(*insertTriggerOid))
