Fix #9161, #9298: Upgrading from old database failed when projects ha…

…d 2+ categories with same name but different case ('Cat' vs 'cat').

admin/install_functions.php

@@ -56,10 +56,17 @@ function install_category_migrate() {
 
 	# In every project, go through all the categories found, and create them and update the bug
 	foreach( $t_data as $t_project_id => $t_categories ) {
+		$t_inserted = array();
 		foreach( $t_categories as $t_name => $t_true ) {
-			$query = "INSERT INTO $t_category_table ( name, project_id ) VALUES ( " . db_param() . ', ' . db_param() . ' )';
-			db_query_bound( $query, array( $t_name, $t_project_id ) );
-			$t_category_id = db_insert_id( $t_category_table );
+			$t_lower_name = mb_strtolower( $t_name );
+			if ( !isset( $t_inserted[$t_lower_name] ) ) {
+				$query = "INSERT INTO $t_category_table ( name, project_id ) VALUES ( " . db_param() . ', ' . db_param() . ' )';
+				db_query_bound( $query, array( $t_name, $t_project_id ) );
+				$t_category_id = db_insert_id( $t_category_table );
+				$t_inserted[$t_lower_name] = $t_category_id;
+			} else {
+				$t_category_id = $t_inserted[$t_lower_name];
+			}
 
 			$query = "UPDATE $t_bug_table SET category_id=" . db_param() . '
 						WHERE project_id=' . db_param() . ' AND category=' . db_param();