From 31988ac63fb6472029f17ef61fd103a19a62404c Mon Sep 17 00:00:00 2001
From: River Tarnell <river@users.mediawiki.org>
Date: Thu, 8 Mar 2007 17:24:52 +0000
Subject: [PATCH] change hardcoded rc_cur_id update into new flexible form

---
 .../archives/patch-rc_cur_id-not-null.sql     |  1 +
 maintenance/updaters.inc                      | 29 +++++++++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 maintenance/postgres/archives/patch-rc_cur_id-not-null.sql

diff --git a/maintenance/postgres/archives/patch-rc_cur_id-not-null.sql b/maintenance/postgres/archives/patch-rc_cur_id-not-null.sql
new file mode 100644
index 0000000000..2ca7edbfb5
--- /dev/null
+++ b/maintenance/postgres/archives/patch-rc_cur_id-not-null.sql
@@ -0,0 +1 @@
+ALTER TABLE recentchanges ALTER rc_cur_id DROP NOT NULL;
diff --git a/maintenance/updaters.inc b/maintenance/updaters.inc
index 5c860d35a6..327878ebbc 100644
--- a/maintenance/updaters.inc
+++ b/maintenance/updaters.inc
@@ -1064,6 +1064,27 @@ END;
 	return $exists;
 }
 
+function
+pg_column_is_nullable($table, $column)
+{
+global	$wgDatabase, $wgDBname, $wgDBmwschema;
+
+	$q = <<<END
+SELECT attnotnull FROM pg_class, pg_namespace, pg_attribute
+	WHERE relnamespace=pg_namespace.oid AND relkind='r'
+	      AND attrelid=pg_class.oid
+	      AND nspname=%s AND relname=%s AND attname=%s;
+END;
+	$res = $wgDatabase->query(sprintf($q,
+			$wgDatabase->addQuotes($wgDBmwschema),
+			$wgDatabase->addQuotes($table),
+			$wgDatabase->addQuotes($column)));
+	$row = $wgDatabase->fetchRow($res);
+	$nullable = ($row[0] === 'f');
+	$wgDatabase->freeResult($res);
+	return $nullable;
+}
+
 function
 pg_table_exists($table)
 {
@@ -1258,13 +1279,15 @@ function do_postgres_updates() {
 		dbsource(archive('patch-page_deleted.sql'));
 	}
 
+	if (!pg_column_is_nullable("recentchanges", "rc_cur_id")) {
+		echo "... remove NOT NULL constraint on recentchanges.rc_cur_id\n";
+		dbsource(archive('patch-rc_cur_id-not-null.sql'));
+	}
+
 	## 1.8 Updater
 	if ($version < 1008) {
 		$upgrade .= <<<PGEND
 
--- Constraint tweaking:
-ALTER TABLE recentchanges ALTER rc_cur_id DROP NOT NULL;
-
 -- Index order rearrangements:
 DROP INDEX pagelink_unique;
 CREATE UNIQUE INDEX pagelink_unique ON pagelinks (pl_from,pl_namespace,pl_title);
-- 
2.20.1