From 18ca26574b0178813e27b0039f6ea86b1b8fa3e0 Mon Sep 17 00:00:00 2001
From: Gary Pendergast <gary@pento.net>
Date: Mon, 23 May 2016 08:36:28 +0000
Subject: [PATCH] Database: `dbDelta()` will no longer try to downgrade the
 size of `TEXT` and `BLOB` columns.

When upgrading to `utf8mb4`, `TEXT` fields will be upgraded to `MEDIUMTEXT` (and likewise for all other `*TEXT` and `*BLOB` fields). This is to allow for the additional space requirements of `utf8mb4`.

On the subsequent upgrade, after the `utf8mb4` upgrade, `dbDelta()` would try and downgrade the fields to their original size again. At best, this it a waste of time, at worst, this could truncate any data larger than the original size. There's no harm in leaving them at their original size, so let's do that.

Fixes #36748.


Built from https://develop.svn.wordpress.org/trunk@37525


git-svn-id: http://core.svn.wordpress.org/trunk@37493 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/upgrade.php | 22 ++++++++++++++++++++--
 wp-includes/version.php       |  2 +-
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/wp-admin/includes/upgrade.php b/wp-admin/includes/upgrade.php
index 05d7f97f28..c8f74733b0 100644
--- a/wp-admin/includes/upgrade.php
+++ b/wp-admin/includes/upgrade.php
@@ -2154,6 +2154,9 @@ function dbDelta( $queries = '', $execute = true ) {
 	 */
 	$iqueries = apply_filters( 'dbdelta_insert_queries', $iqueries );
 
+	$text_fields = array( 'tinytext', 'text', 'mediumtext', 'longtext' );
+	$blob_fields = array( 'tinyblob', 'blob', 'mediumblob', 'longblob' );
+
 	$global_tables = $wpdb->tables( 'global' );
 	foreach ( $cqueries as $table => $qry ) {
 		// Upgrade global tables only for the main site. Don't upgrade at all if conditions are not optimal.
@@ -2223,9 +2226,24 @@ function dbDelta( $queries = '', $execute = true ) {
 
 				// Is actual field type different from the field type in query?
 				if ($tablefield->Type != $fieldtype) {
+					$do_change = true;
+					if ( in_array( strtolower( $fieldtype ), $text_fields ) && in_array( strtolower( $tablefield->Type ), $text_fields ) ) {
+						if ( array_search( strtolower( $fieldtype ), $text_fields ) < array_search( strtolower( $tablefield->Type ), $text_fields ) ) {
+							$do_change = false;
+						}
+					}
+
+					if ( in_array( strtolower( $fieldtype ), $blob_fields ) && in_array( strtolower( $tablefield->Type ), $blob_fields ) ) {
+						if ( array_search( strtolower( $fieldtype ), $blob_fields ) < array_search( strtolower( $tablefield->Type ), $blob_fields ) ) {
+							$do_change = false;
+						}
+					}
+
+					if ( $do_change ) {
 					// Add a query to change the column type
-					$cqueries[] = "ALTER TABLE {$table} CHANGE COLUMN {$tablefield->Field} " . $cfields[strtolower($tablefield->Field)];
-					$for_update[$table.'.'.$tablefield->Field] = "Changed type of {$table}.{$tablefield->Field} from {$tablefield->Type} to {$fieldtype}";
+						$cqueries[] = "ALTER TABLE {$table} CHANGE COLUMN {$tablefield->Field} " . $cfields[strtolower($tablefield->Field)];
+						$for_update[$table.'.'.$tablefield->Field] = "Changed type of {$table}.{$tablefield->Field} from {$tablefield->Type} to {$fieldtype}";
+					}
 				}
 
 				// Get the default value from the array
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0d5c8fe1ac..92a58b6353 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37524';
+$wp_version = '4.6-alpha-37525';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.