psql: Add tab completion for logical replication

Add tab completion for publications and subscriptions.  Also, to be able
to get a list of subscriptions, make pg_subscription world-readable but
revoke access to subconninfo using column privileges.

From: Michael Paquier <michael.paquier@gmail.com>

doc/src/sgml/catalogs.sgml

@@ -6324,9 +6324,8 @@
   </para>
 
   <para>
-   Access to this catalog is restricted from normal users.  Normal users can
+   Access to the column <structfield>subconninfo</structfield> is revoked from
-   use the view <xref linkend="pg-stat-subscription"> to get some information
+   normal users, because it could contain plain-text passwords.
-   about subscriptions.
   </para>
 
   <table>

src/backend/catalog/system_views.sql

@@ -900,7 +900,11 @@ CREATE VIEW pg_replication_origin_status AS
 
 REVOKE ALL ON pg_replication_origin_status FROM public;
 
+-- All columns of pg_subscription except subconninfo are readable.
 REVOKE ALL ON pg_subscription FROM public;
+GRANT SELECT (subdbid, subname, subowner, subenabled, subslotname, subpublications)
+    ON pg_subscription TO public;
+
 
 --
 -- We have a few function definitions in here, too.

src/bin/psql/tab-complete.c

@@ -845,6 +845,18 @@ static const SchemaQuery Query_for_list_of_matviews = {
 "   FROM pg_catalog.pg_am "\
 "  WHERE substring(pg_catalog.quote_ident(amname),1,%d)='%s'"
 
+#define Query_for_list_of_publications \
+" SELECT pg_catalog.quote_ident(pubname) "\
+"   FROM pg_catalog.pg_publication "\
+"  WHERE substring(pg_catalog.quote_ident(pubname),1,%d)='%s'"
+
+#define Query_for_list_of_subscriptions \
+" SELECT pg_catalog.quote_ident(s.subname) "\
+"   FROM pg_catalog.pg_subscription s, pg_catalog.pg_database d "\
+"  WHERE substring(pg_catalog.quote_ident(s.subname),1,%d)='%s' "\
+"    AND d.datname = pg_catalog.current_database() "\
+"    AND s.subdbid = d.oid"
+
 /* the silly-looking length condition is just to eat up the current word */
 #define Query_for_list_of_arguments \
 "SELECT pg_catalog.oidvectortypes(proargtypes)||')' "\
@@ -985,13 +997,13 @@ static const pgsql_thing_t words_after_create[] = {
 	{"OWNED", NULL, NULL, THING_NO_CREATE},		/* for DROP OWNED BY ... */
 	{"PARSER", Query_for_list_of_ts_parsers, NULL, THING_NO_SHOW},
 	{"POLICY", NULL, NULL},
-	{"PUBLICATION", NULL, NULL},
+	{"PUBLICATION", Query_for_list_of_publications},
 	{"ROLE", Query_for_list_of_roles},
 	{"RULE", "SELECT pg_catalog.quote_ident(rulename) FROM pg_catalog.pg_rules WHERE substring(pg_catalog.quote_ident(rulename),1,%d)='%s'"},
 	{"SCHEMA", Query_for_list_of_schemas},
 	{"SEQUENCE", NULL, &Query_for_list_of_sequences},
 	{"SERVER", Query_for_list_of_servers},
-	{"SUBSCRIPTION", NULL, NULL},
+	{"SUBSCRIPTION", Query_for_list_of_subscriptions},
 	{"TABLE", NULL, &Query_for_list_of_tables},
 	{"TABLESPACE", Query_for_list_of_tablespaces},
 	{"TEMP", NULL, NULL, THING_NO_DROP},		/* for CREATE TEMP TABLE ... */
@@ -2376,6 +2388,11 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_CONST("CONNECTION");
 	else if (Matches5("CREATE", "SUBSCRIPTION", MatchAny, "CONNECTION", MatchAny))
 		COMPLETE_WITH_CONST("PUBLICATION");
+	else if (Matches6("CREATE", "SUBSCRIPTION", MatchAny, "CONNECTION",
+					  MatchAny, "PUBLICATION"))
+	{
+		/* complete with nothing here as this refers to remote publications */
+	}
 	/* Complete "CREATE SUBSCRIPTION <name> ...  WITH ( <opt>" */
 	else if (HeadMatches2("CREATE", "SUBSCRIPTION") && TailMatches2("WITH", "("))
 		COMPLETE_WITH_LIST5("ENABLED", "DISABLED", "CREATE SLOT",

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201703031
+#define CATALOG_VERSION_NO	201703032
 
 #endif

src/include/catalog/pg_subscription.h

@@ -27,6 +27,8 @@
  * seems weird, but the replication launcher process needs to access all of
  * them to be able to start the workers, so we have to put them in a shared,
  * nailed catalog.
+ *
+ * NOTE:  When adding a column, also update system_views.sql.
  */
 CATALOG(pg_subscription,6100) BKI_SHARED_RELATION BKI_ROWTYPE_OID(6101) BKI_SCHEMA_MACRO
 {