X-Git-Url: http://git.heureux-cyclage.org/?a=blobdiff_plain;f=includes%2FDefines.php;h=ca603e76845745d82290dd9975c491281026e6b7;hb=587d08c5a626f8195def9f82ee83e17c85824db8;hp=6bc70edbc500534a793c8c31ceae07895b659180;hpb=cf35ff756c89ca6d6e003b440076df5ebe7ccef7;p=lhc%2Fweb%2Fwiklou.git

diff --git a/includes/Defines.php b/includes/Defines.php
index 6bc70edbc5..ca603e7684 100644
--- a/includes/Defines.php
+++ b/includes/Defines.php
@@ -31,6 +31,9 @@ use Wikimedia\Rdbms\IDatabase;
  */
 
 # Obsolete aliases
+/**
+ * @deprecated since 1.28
+ */
 define( 'DB_SLAVE', -1 );
 
 /**@{
@@ -267,3 +270,28 @@ define( 'CONTENT_FORMAT_XML', 'application/xml' );
  */
 define( 'SHELL_MAX_ARG_STRLEN', '100000' );
 /**@}*/
+
+/**@{
+ * Schema change migration flags.
+ *
+ * Used as values of a feature flag for an orderly transition from an old
+ * schema to a new schema.
+ *
+ * - MIGRATION_OLD: Only read and write the old schema. The new schema need not
+ *   even exist. This is used from when the patch is merged until the schema
+ *   change is actually applied to the database.
+ * - MIGRATION_WRITE_BOTH: Write both the old and new schema. Read the new
+ *   schema preferentially, falling back to the old. This is used while the
+ *   change is being tested, allowing easy roll-back to the old schema.
+ * - MIGRATION_WRITE_NEW: Write only the new schema. Read the new schema
+ *   preferentially, falling back to the old. This is used while running the
+ *   maintenance script to migrate existing entries in the old schema to the
+ *   new schema.
+ * - MIGRATION_NEW: Only read and write the new schema. The old schema (and the
+ *   feature flag) may now be removed.
+ */
+define( 'MIGRATION_OLD', 0 );
+define( 'MIGRATION_WRITE_BOTH', 1 );
+define( 'MIGRATION_WRITE_NEW', 2 );
+define( 'MIGRATION_NEW', 3 );
+/**@}*/