Fix GetForeignKey*Triggers for self-referential FKs

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 f4566345cf40, 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
index f687a98bcc9d662cfa9f8a87453541e1e2168545..bc748f8e1acb21373541af975027e2480b2b4ed5 100644 (file)
--- 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))