Fix contrib/citext's upgrade script to handle array and domain cases.

We previously recognized that citext wouldn't get marked as collatable
during pg_upgrade from a pre-9.1 installation, and hacked its
create-from-unpackaged script to manually perform the necessary catalog
adjustments.  However, we overlooked the fact that domains over citext,
as well as the citext[] array type, need the same adjustments.  Extend
the script to handle those cases.

Also, the documentation suggested that this was only an issue in pg_upgrade
scenarios, which is quite wrong; loading any dump containing citext from a
pre-9.1 server will also result in the type being wrongly marked.

I approached the documentation problem by changing the 9.1.2 release note
paragraphs about this issue, which is historically inaccurate.  But it
seems better than having the information scattered in multiple places, and
leaving incorrect info in the 9.1.2 notes would be bad anyway.  We'll still
need to mention the issue again in the 9.1.4 notes, but perhaps they can
just reference 9.1.2 for fix instructions.

Per report from Evan Carroll.  Back-patch into 9.1.

contrib/citext/citext--unpackaged--1.0.sql

@@ -81,49 +81,108 @@ ALTER EXTENSION citext ADD function translate(citext,citext,text);
 --
 -- As of 9.1, type citext should be marked collatable.  There is no ALTER TYPE
 -- command for this, so we have to do it by poking the pg_type entry directly.
--- We have to poke any derived copies in pg_attribute or pg_index as well.
+-- We have to poke any derived copies in pg_attribute or pg_index as well,
+-- as well as those for arrays/domains based directly or indirectly on citext.
 -- Notes: 100 is the OID of the "pg_catalog.default" collation --- it seems
 -- easier and more reliable to hard-wire that here than to pull it out of
 -- pg_collation.  Also, we don't need to make pg_depend entries since the
 -- default collation is pinned.
 --
 
+WITH RECURSIVE typeoids(typoid) AS
+  ( SELECT 'citext'::pg_catalog.regtype UNION
+    SELECT oid FROM pg_catalog.pg_type, typeoids
+      WHERE typelem = typoid OR typbasetype = typoid )
 UPDATE pg_catalog.pg_type SET typcollation = 100
-WHERE oid = 'citext'::pg_catalog.regtype;
+FROM typeoids
+WHERE oid = typeoids.typoid;
 
+WITH RECURSIVE typeoids(typoid) AS
+  ( SELECT 'citext'::pg_catalog.regtype UNION
+    SELECT oid FROM pg_catalog.pg_type, typeoids
+      WHERE typelem = typoid OR typbasetype = typoid )
 UPDATE pg_catalog.pg_attribute SET attcollation = 100
-WHERE atttypid = 'citext'::pg_catalog.regtype;
+FROM typeoids
+WHERE atttypid = typeoids.typoid;
 
 UPDATE pg_catalog.pg_index SET indcollation[0] = 100
-WHERE indclass[0] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[0] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[1] = 100
-WHERE indclass[1] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[1] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[2] = 100
-WHERE indclass[2] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[2] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[3] = 100
-WHERE indclass[3] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[3] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[4] = 100
-WHERE indclass[4] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[4] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[5] = 100
-WHERE indclass[5] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[5] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[6] = 100
-WHERE indclass[6] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[6] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 UPDATE pg_catalog.pg_index SET indcollation[7] = 100
-WHERE indclass[7] IN (SELECT oid FROM pg_catalog.pg_opclass
-                      WHERE opcintype = 'citext'::pg_catalog.regtype);
+WHERE indclass[7] IN (
+  WITH RECURSIVE typeoids(typoid) AS
+    ( SELECT 'citext'::pg_catalog.regtype UNION
+      SELECT oid FROM pg_catalog.pg_type, typeoids
+        WHERE typelem = typoid OR typbasetype = typoid )
+  SELECT oid FROM pg_catalog.pg_opclass, typeoids
+  WHERE opcintype = typeoids.typoid
+);
 
 -- somewhat arbitrarily, we assume no citext indexes have more than 8 columns

doc/src/sgml/release-9.1.sgml

@@ -667,10 +667,13 @@
    </para>
 
    <para>
-    Also, if your installation was upgraded from a previous major release
-    by running <application>pg_upgrade</>, and it contains table columns of
-    the <type>citext</> data type, you should run <literal>CREATE EXTENSION
-    citext FROM unpackaged</>.  If you've already done that before
+    Also, if you use the <type>citext</> data type, and you upgraded
+    from a previous major release by running <application>pg_upgrade</>,
+    you should run <literal>CREATE EXTENSION citext FROM unpackaged</>
+    to avoid collation-related failures in <type>citext</> operations.
+    The same is necessary if you restore a dump from a pre-9.1 database
+    that contains an instance of the <type>citext</> data type.
+    If you've already run the <command>CREATE EXTENSION</> command before
     upgrading to 9.1.2, you will instead need to do manual catalog updates
     as explained in the second changelog item.
    </para>
@@ -717,7 +720,9 @@
      <para>
       Existing <type>citext</> columns and indexes aren't correctly marked as
       being of a collatable data type during <application>pg_upgrade</> from
-      a pre-9.1 server.  That leads to operations on them failing with errors
+      a pre-9.1 server, or when a pre-9.1 dump containing the <type>citext</>
+      type is loaded into a 9.1 server.
+      That leads to operations on these columns failing with errors
       such as <quote>could not determine which collation to use for string
       comparison</>.  This change allows them to be fixed by the same
       script that upgrades the <type>citext</> module into a proper 9.1
@@ -732,6 +737,7 @@
       <filename><replaceable>SHAREDIR</>/extension/citext--unpackaged--1.0.sql</filename>.
       (Run <literal>pg_config --sharedir</> if you're uncertain where
       <replaceable>SHAREDIR</> is.)
+      There is no harm in doing this again if unsure.
      </para>
     </listitem>