pg_dump: Fix dumping of security labels on subscriptions and event triggers.

Previously, pg_dump incorrectly queried pg_seclabel to retrieve security labels
for subscriptions, which are stored in pg_shseclabel as they are global objects.
This could result in security labels for subscriptions not being dumped.

This commit fixes the issue by updating pg_dump to query the pg_seclabels view,
which aggregates entries from both pg_seclabel and pg_shseclabel.
While querying pg_shseclabel directly for subscriptions was an alternative,
using pg_seclabels is simpler and sufficient.

In addition, pg_dump is updated to dump security labels on event triggers,
which were previously omitted.

Backpatch to all supported versions.

Author: Jian He <jian.universality@gmail.com>
Co-authored-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/CACJufxHCt00pR9h51AVu6+yPD5J7JQn=7dQXxqacj0XyDhc-fA@mail.gmail.com
Backpatch-through: 13

src/bin/pg_dump/pg_backup_archiver.c

@@ -3125,12 +3125,14 @@ _tocEntryRestorePass(TocEntry *te)
 		return RESTORE_PASS_POST_ACL;
 
 	/*
-	 * Comments need to be emitted in the same pass as their parent objects.
-	 * ACLs haven't got comments, and neither do matview data objects, but
-	 * event triggers do.  (Fortunately, event triggers haven't got ACLs, or
-	 * we'd need yet another weird special case.)
+	 * Comments and security labels need to be emitted in the same pass as
+	 * their parent objects. ACLs haven't got comments and security labels,
+	 * and neither do matview data objects, but event triggers do.
+	 * (Fortunately, event triggers haven't got ACLs, or we'd need yet another
+	 * weird special case.)
 	 */
-	if (strcmp(te->desc, "COMMENT") == 0 &&
+	if ((strcmp(te->desc, "COMMENT") == 0 ||
+		 strcmp(te->desc, "SECURITY LABEL") == 0) &&
 		strncmp(te->tag, "EVENT TRIGGER ", 14) == 0)
 		return RESTORE_PASS_POST_ACL;
 

src/bin/pg_dump/pg_dump.c

@@ -15840,7 +15840,7 @@ collectSecLabels(Archive *fout, SecLabelItem **items)
 
 	appendPQExpBufferStr(query,
 						 "SELECT label, provider, classoid, objoid, objsubid "
-						 "FROM pg_catalog.pg_seclabel "
+						 "FROM pg_catalog.pg_seclabels "
 						 "ORDER BY classoid, objoid, objsubid");
 
 	res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
@@ -18301,6 +18301,11 @@ dumpEventTrigger(Archive *fout, const EventTriggerInfo *evtinfo)
 					NULL, evtinfo->evtowner,
 					evtinfo->dobj.catId, 0, evtinfo->dobj.dumpId);
 
+	if (evtinfo->dobj.dump & DUMP_COMPONENT_SECLABEL)
+		dumpSecLabel(fout, "EVENT TRIGGER", qevtname,
+					 NULL, evtinfo->evtowner,
+					 evtinfo->dobj.catId, 0, evtinfo->dobj.dumpId);
+
 	destroyPQExpBuffer(query);
 	destroyPQExpBuffer(delqry);
 	free(qevtname);