Index: openacs-4/packages/categories/categories.info
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/categories.info,v
diff -u -N -r1.21 -r1.21.2.1
--- openacs-4/packages/categories/categories.info	31 Jan 2018 08:23:12 -0000	1.21
+++ openacs-4/packages/categories/categories.info	16 Apr 2019 13:52:12 -0000	1.21.2.1
@@ -10,7 +10,7 @@
     <inherit-templates-p>t</inherit-templates-p>
     <auto-mount>categories</auto-mount>
 
-    <version name="1.1.4" url="http://openacs.org/repository/apm/packages/categories-1.1.4">
+    <version name="1.1.5d1" url="http://openacs.org/repository/apm/packages/categories-1.1.5d1">
         <owner url="mailto:timo@timohentschel.de">timo@timohentschel.de</owner>
         <summary>Manage categories in category trees and let users map objects to categories.</summary>
         <release-date>2017-08-06</release-date>
@@ -19,7 +19,7 @@
         <license>GPL</license>
         <maturity>1</maturity>
 
-        <provides url="categories" version="1.1.4"/>
+        <provides url="categories" version="1.1.5d1"/>
         <requires url="acs-kernel" version="5.9.1"/>
 
         <callbacks>
Index: openacs-4/packages/categories/sql/postgresql/category-package.sql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/sql/postgresql/category-package.sql,v
diff -u -N -r1.9 -r1.9.2.1
--- openacs-4/packages/categories/sql/postgresql/category-package.sql	7 Aug 2017 23:48:05 -0000	1.9
+++ openacs-4/packages/categories/sql/postgresql/category-package.sql	16 Apr 2019 13:52:12 -0000	1.9.2.1
@@ -314,7 +314,7 @@
 	and left_ind > v_old_left_ind;
 
 	if (p_parent_id is null) then
-	   select 1, max(right_ind)+1 into v_new_left_ind, v_new_right_ind
+	   select 1, coalesce(max(right_ind)+1, 1) into v_new_left_ind, v_new_right_ind
 	   from categories
 	   where tree_id = p_tree_id;
 	else
Index: openacs-4/packages/categories/sql/postgresql/upgrade/upgrade-1.1.4-1.1.5d1.sql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/sql/postgresql/upgrade/Attic/upgrade-1.1.4-1.1.5d1.sql,v
diff -u -N
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ openacs-4/packages/categories/sql/postgresql/upgrade/upgrade-1.1.4-1.1.5d1.sql	16 Apr 2019 13:52:12 -0000	1.1.2.1
@@ -0,0 +1,89 @@
+
+--
+-- procedure category__change_parent/3
+--
+CREATE OR REPLACE FUNCTION category__change_parent(
+   p_category_id integer,
+   p_tree_id integer,
+   p_parent_id integer
+) RETURNS integer AS $$
+DECLARE
+
+    v_old_left_ind      integer;
+    v_old_right_ind     integer;
+    v_new_left_ind      integer;
+    v_new_right_ind     integer;
+    v_width             integer;
+BEGIN
+ 	update categories
+	set parent_id = p_parent_id
+	where category_id = p_category_id;
+
+	-- first save the subtree, then compact tree, then expand tree to make room
+	-- for subtree, then insert it
+
+	select left_ind, right_ind into v_old_left_ind, v_old_right_ind
+	from categories
+	where category_id = p_category_id;
+
+	v_width := v_old_right_ind - v_old_left_ind + 1;
+
+	-- cut out old subtree
+	update categories
+	set left_ind = -left_ind, right_ind = -right_ind
+	where tree_id = p_tree_id
+	and left_ind >= v_old_left_ind
+	and right_ind <= v_old_right_ind;
+
+	-- compact parent trees
+	update categories
+	set right_ind = right_ind - v_width
+	where tree_id = p_tree_id
+	and left_ind < v_old_left_ind
+	and right_ind > v_old_right_ind;
+
+	-- compact right tree portion
+	update categories
+	set left_ind = left_ind - v_width,
+	right_ind = right_ind - v_width
+	where tree_id = p_tree_id
+	and left_ind > v_old_left_ind;
+
+	if (p_parent_id is null) then
+	   select 1, coalesce(max(right_ind)+1, 1) into v_new_left_ind, v_new_right_ind
+	   from categories
+	   where tree_id = p_tree_id;
+	else
+	   select left_ind, right_ind into v_new_left_ind, v_new_right_ind
+	   from categories
+	   where category_id = p_parent_id;
+	end if;
+
+	-- move parent trees to make room
+	update categories
+	set right_ind = right_ind + v_width
+	where tree_id = p_tree_id
+	and left_ind <= v_new_left_ind
+	and right_ind >= v_new_right_ind;
+
+	-- move right tree portion to make room
+	update categories
+	set left_ind = left_ind + v_width,
+	right_ind = right_ind + v_width
+	where tree_id = p_tree_id
+	and left_ind > v_new_right_ind;
+
+	-- insert subtree at correct place
+	update categories
+	set left_ind = -left_ind + (v_new_right_ind - v_old_left_ind),
+	right_ind = -right_ind + (v_new_right_ind - v_old_left_ind)
+	where tree_id = p_tree_id
+	and left_ind < 0;
+
+	-- for debugging reasons
+        perform category_tree__check_nested_ind(p_tree_id);
+
+        return 0;
+END;
+
+$$ LANGUAGE plpgsql;