silverstripe-framework/docs/en/04_Changelogs/4.0.0.md

# 4.0.0 (unreleased)

## Overview

### Framework

 * Minimum PHP version raised to 5.5.0
 * Minimum CMS browser requirement raised from Internet Explorer 8 to Internet Explorer 10
 * Deprecate `SQLQuery` in favour `SQLSelect`
 * `DataList::filter` by null now internally generates "IS NULL" or "IS NOT NULL" conditions appropriately on queries
 * `DataObject` constructor now has an additional parameter, which must be included in subclasses.
 * `DataObject::database_fields` now returns all fields on that table.
 * `DataObject::db` now returns composite fields.
 * `DataObject::ClassName` field has been refactored into a `DBClassName` type field.
 * Image manipulations have been moved into a new `[api:ImageManipulation]` trait.
 * `CMSFileAddController` removed.
 * `UploadField::setAllowedFileCategories('image')` now excludes non-resizeable images. 'unresizeable_image' is
   can be used to validate these types.
 * `Image_Backend` API now loads and saves from `AssetContainer` instances rather than local files.
 * The following File categories have been renamed: 'zip' to 'archive', 'doc' to 'document', and 'mov' to 'video'
 * `File::updateLinks` no longer takes urls as parameters. All file links are now identified either by
   the `DataObject::ID` in a `data-fileid` property, or via shortcodes. This is necessary because file
   urls are no longer able to identify assets.
 * Extension point `HtmlEditorField::processImage` has been removed, and moved to `Image::regenerateImageHTML`
 * `Upload::load` now stores assets directly without saving into a `File` dataobject.
 * Protected file storage is now a core Framework API. See [/developer_guides/files/file_security] for
   more information.
 * `Object::useCustomClass` has been removed. You should use the config API with Injector instead.
 * Upgrade of TinyMCE to version 4.
 * `File` is now versioned, and should be published before they can be used on the frontend.
   See section on [Migrating File DataObject from 3.x to 4.0](#migrating-file-dataobject-from-3x-to-40)
   below for upgrade notes.
 * Removed `dev/tests/` controller in favour of standard `vendor/bin/phpunit` command
 * Updated PHPUnit from 3.7 to 4.8 ([upgrade notes](https://github.com/sebastianbergmann/phpunit/wiki/Release-Announcement-for-PHPUnit-4.0.0#backwards-compatibility-issues)). 
   Please remove any PHPUnit related `require_once()` calls (e.g. in `FeatureContext` 
   definitions of the [behat-extension](https://github.com/silverstripe-labs/silverstripe-behat-extension) module).
   Run `composer require --dev 'phpunit/phpunit:~4.8'` on existing projects to pull in the new dependency.
 * `Object::invokeWithExtensions` now has the same method signature as `Object::extend` and behaves the same way.
 * `CMSMain` model actions have been changed:
   * `CMSBatchAction_Delete` and `CMSMain::delete` are no longer deprecated.
   * `CMSBatchAction_DeleteFromLive` is removed.
   * `CMSMain.enabled_legacy_actions` config is removed.
 * `DataObject::can` has new method signature with `$context` parameter.

## New API

 * New filesystem abstraction including new `DBFile` database field to hold file references.
 * `ShortcodeHandler` interface to help generate standard handlers for HTML shortcodes in the editor.
 * `AssetNameGenerator` interface, including a `DefaultAssetNameGenerator` implementation, which is used to generate
   renaming suggestions based on an original given filename in order to resolve file duplication issues.
 * `GeneratedAssetHandler` API now used to store and manage generated files (such as those used for error page
   cache or combined files).
 * `Requirements_Minifier` API can be used to declare any new mechanism for minifying combined required files.
   By default this api is provided by the `JSMinifier` class, but user code can substitute their own.
 * `AssetField` formfield to provide an `UploadField` style uploader for the new `DBFile` database field.
 * `AssetControlExtension` is applied by default to all DataObjects, in order to support the management
   of linked assets and file protection.
 * `ProtectedFileController` class is used to serve up protected assets.
 * `Object` has been broken up into various traits, each of which can be added to other objects independently:
    * `Configurable` Provides Config API helper methods
    * `Injectable` Provides Injector API helper methods
    * `Extensible` Allows extensions to be applied
 * Removed ability to run tests via web requests (`http://mydomain.com/dev/tests`), use the standard CLI command instead (`vendor/bin/phpunit`)
 * Removed `dev/jstests/` controller (no replacement)
 * Moved test database cleanup task from `sake dev/tests/cleanupdb` to `sake dev/tasks/CleanupTestDatabasesTask`
 * Removed `TestRunner` and `JSTestRunner` APIs
 * Removed `PhpUnitWrapper`, `PhpUnitWrapper_3_4`, `PhpUnitWrapper_3_5`, `PhpUnitWrapper_Generic`, `SapphireTestSuite` APIs
 * Removed `SapphireTest->skipTest`, use `markTestSkipped()` in a `setUp()` method instead
 * `HtmlEditorConfig` is now an abstract class, with a default implementation `TinyMCEConfig` for the built in
   TinyMCE editor.
 * `HtmlEditorField::setEditorConfig` may now take an instance of a `HtmlEditorConfig` class, as well as a
   standard config identifier name.
 * A lot of standard versioned API has been refactored from `SiteTree` into `Versioned` extension. Now
   all versioned DataObjects have `canPublish()`, `canArchive()`, `canUnpublish()`, `doPublish()`, `doArchive()`
   `doUnpublish()`, `isPublished()` and `isonDraft()` out of the box. However, `do*()` methods will no longer
   automatically check `can*()` permissions, and must be done by usercode before invocation.
 * GridField edit form now has improved support for versioned DataObjects, with basic publishing
   actions available when editing records.
 * `Versioned` API has some breaking changes:
   * Versioned constructor now only allows a single string to declare whether staging is enabled or not. The
     number of names of stages are no longer able to be specified. See below for upgrading notes for models
     with custom stages.
   * `reading_stage` is now `set_stage`
   * `current_stage` is now `get_stage`
   * `getVersionedStages` is gone.
   * `get_live_stage` is removed. Use the `Versioned::LIVE` constant instead.
   * `getDefaultStage` is removed. Use the `Versioned::DRAFT` constant instead.
   * `$versionableExtensions` is now `private static` instead of `protected static`
   * `hasStages` is addded to check if an object has a given stage.
   * `stageTable` is added to get the table for a given class and stage.
 * `ChangeSet` and `ChangeSetItem` have been added for batch publishing of versioned dataobjects.

### Front-end build tooling for CMS interface

 * Management of CMS JavaScript dependencies via [npm](https://www.npmjs.com/)
 * ES6 is now available in all core JavaScript files via [Babel](https://babeljs.io/)
 * Bundling of core JavaScript via [Browserify](http://browserify.org/)
 * CMS build tasks managed by [Gulp](http://gulpjs.com/)

For more details see the docs on [working with client-side dependencies](../contributing/code#working-with-client-side-dependencies). Note that you don't need any of these tools for running SilverStripe
or developing your own website. These improvements are mainly geared at CMS core development.

### Added new front-end UI libraries

 * Added the following npm libraries:
   * [react](https://www.npmjs.com/package/react)
   * [redux](https://www.npmjs.com/package/redux)
   * [react-redux](https://www.npmjs.com/package/react-redux)
   * [react-dom](https://www.npmjs.com/package/react-dom)
   * [isomorphic-fetch](https://www.npmjs.com/package/isomorphic-fetch)
   * [redux-thunk](https://www.npmjs.com/package/redux-thunk)
   * [react-addons-test-utils](https://www.npmjs.com/package/react-addons-test-utils)
 * Added SilverStripeComponent base class for building React UIs

### Compiling CSS

[Compass](http://compass-style.org/) has been removed and css/sprite compilation is now handled with [gulp](http://gulpjs.com/) (see [Markup and Style Conventions](../developer_guides/customising_the_admin_interface/cms_architecture/#markup-and-style-conventions)).

### Bootstrap CSS

Bootstrap 4 Alpha.2 CSS is available in `admin/css/bootstrap`.

## Deprecated classes/methods

### Core
 * Added the following npm libraries: 
   * Page.js
 
 * Removed the following JavaScript libraries:
   * History.js

 * `debugmethods` querystring argument has been removed from debugging.

### ORM

 * `DataList::getRelation` is removed, as it was mutable. Use `DataList::applyRelation` instead, which is immutable.

### ErrorPage

 * `ErrorPage.static_filepath` config has been removed.
 * `ErrorPage::get_filepath_for_errorcode` has been removed
 * `ErrorPage::alternateFilepathForErrorcode` extension point has been removed

See notes below on upgrading extensions to the ErrorPage class

### Member

 * `Member` Field 'RememberLoginToken' removed, replaced with 'RememberLoginHashes' has_many relationship

### Assets and Filesystem

The following image manipulations previously deprecated has been removed:

 * `Image::SetRatioSize` superceded by `Fit`
 * `Image::SetWidth` superceded by `ScaleWidth`
 * `Image::SetHeight` superceded by `ScaleHeight`
 * `Image::SetSize` superceded by `Pad`
 * `Image::PaddedImage` superceded by `Pad`
 * `Image::CroppedImage` superceded by `Fill`
 * `Image::AssetLibraryPreview` superceded by `PreviewThumbnail`
 * `Image::AssetLibraryThumbnail` superceded by `CMSThumbnail`

The following `File` methods have been removed. Since there is no longer any assumed local path for any file,
methods which dealt with such paths may no longer be relied on.

 * `File::deletedatabaseOnly`
 * `File::link_shortcode_handler` renamed to `handle_shortcode`
 * `File::setParentID`
 * `File::getFullPath`
 * `File::getRelativePath`
 * `File::Content` database field is removed

Image manipulations have been moved out of Image.php and now available to any File or DBFile which has the
appropriate mime types. The following file manipulations classes and methods have been removed:

 * `CleanImageManipulationCache` class
 * `Image_Cached` class
 * `Image::regenerateFormattedImages`
 * `Image::getGeneratedImages`
 * `Image::deleteFormattedImages`
 * `AssetAdmin::deleteunusedthumbnails`
 * `AssetAdmin::getUnusedThumbnails`

Many `Folder` methods have also been removed:

 * `Folder::syncChildren`
 * `Folder::constructChild`
 * `Folder::addUploadToFolder`

The following filesystem synchronisation methods are also removed

 * `Filesystem::sync`
 * `AssetAdmin::doSync`

The Spyc YAML library has been removed from /thirdparty. Please load it yourself, or use the Symfony YAML component that’s automatically installed by composer.

### Requirements

The following methods and properties on `Requirements_Backend` have been renamed:

 * `Requirements_Backund::$combine_files` made protected and renamed `$combinedFiles`
 * `Requirements_Backend::$combine_js_with_min` made protected and renamed `$minifyCombinedFiles`
 * `Requirements_Backend::$write_header_comments` made protected and renamed `$writeHeaderComment`
 * `Requirements_Backend::$write_js_to_body` made protected and renamed to `$writeJavascriptToBody`
 * `Requirements_Backend::$force_js_to_bottom` renamed to `$forceJSToBottom`
 * `get_combined_files_enabled` renamed to `getCombinedFilesEnabled`
 * `set_combined_files_enabled` renamed to `setCombinedFilesEnabled`
 * `get_suffix_requirements` renamed to `getSuffixRequirements`
 * `set_suffix_requirements` renamed to `setSuffixRequirements`
 * `get_custom_scripts` renamed to `getCustomScripts`
 * `unblock_all` renamed to `unblockAll`
 * `include_in_response` renamed to `includeInResponse`
 * `combine_files` renamed to `combineFiles`
 * `get_combine_files` renamed to `getCombinedFiles`
 * `clear_combined_files` renamed to `clearCombinedFiles`
 * `process_combined_files` renamed to `processCombinedFiles`
 * `set_write_js_to_body` renamed to `setWriteJavascriptToBody`
 * `set_force_js_to_bottom` renamed to `setForceJSToBottom`

New methods on `Requirements` are added to access these:

 * `get_minify_combined_js_files`
 * `set_minify_combined_js_files`
 * `get_force_js_to_bottom`
 * `get_write_js_to_body`
 
Some methods on `Requirements` have had their method signatures changed:

 * `includeInHTML` has had the first parameter $template removed as it was previously deprecated.

And some methods on `Requirements` and `Requirements_Backend` have been removed as they are obsolete.

 * `delete_combined_files` (both classes)

A new config `Requirements_Backend.combine_in_dev` has been added in order to allow combined files to be
forced on during development. If this is off, combined files is only enabled in live environments.

In addition, a new API for javascript files has been added to support front-end tools
such as [browserify](http://browserify.org/) that pre-combine scripts. You can specify
a 'provides' option to the second parameter of `Requirements::javascript` to declare
included files.

E.g.


    :::php
    Requirements::javascript('mysite/js/dist/bundle.js', ['provides' => [
        'mysite/js/jquery.js'
        'mysite/js/src/main.js',
        'mysite/js/src/functions.js'
    ]]);


## Upgrading

### Update code that uses SQLQuery

Where your code once used SQLQuery you should now use SQLSelect in all cases, as this has been removed.

See the [3.2.0](3.2.0) upgrading notes for details on how existing code should be upgraded.

### New asset storage mechanism

File system has been abstracted into an abstract interface. By default, the out of the box filesystem
uses [Flysystem](http://flysystem.thephpleague.com/) with a local storage mechanism (under the assets directory).

Because the filesystem now uses the sha1 of file contents in order to version multiple versions under the same
filename, the default storage paths in 4.0 will not be the same as in 3.

In order to retain existing file paths in line with framework version 3 you should set the
`\SilverStripe\Filesystem\Flysystem\FlysystemAssetStore.legacy_paths` config to true.
Note that this will not allow you to utilise certain file versioning features in 4.0.


	:::yaml
	\SilverStripe\Filesystem\Flysystem\FlysystemAssetStore:
	  legacy_paths: true


See [/developer_guides/files/file_management] for more information on how the new system works.

### Migrating File DataObject from 3.x to 4.0

Since the structure of `File` dataobjects has changed, a new task `MigrateFileTask` has been added to assist
in migration of legacy files. Migration can be invoked by either this task, or can be configured to automatically
run during dev build by setting the `File.migrate_legacy_file` config to true. However, it's recommended that
this task is run manually during an explicit migration process, as this process could potentially consume
large amounts of memory and run for an extended time.


	:::yaml
	File:
	  migrate_legacy_file: true


This task will also support migration of existing File DataObjects to file versioning. Any
pre-existing File DataObjects will be automatically published to the live stage, to ensure
that previously visible assets remain visible to the public site.

If additional security or visibility rules should be applied to File dataobjects, then
make sure to correctly extend `canView` via extensions.

### Upgrade code which acts on `Image`

As all image-specific manipulations has been refactored from `Image` into an `ImageManipulations` trait, which 
is applied to both `File` and `DBFile`. These both implement a common interface `AssetContainer`, which
has the `getIsImage()` method. In some cases, it may be preferable to invoke this method to detect
if the asset is an image or not, rather than checking the subclass, as the asset may also be a `DBFile` with
an image filter applied, rather than an instance of the `Image` dataobject.

In addition, a new file category `image/supported` has been added, which is a subset of the `image` category.
This is the subset of all image types which may be assigned to the `[api:Image]` dataobject, and may have
manipulations applied to it. This should be used as the file type restriction on any `[api:UploadField]` which
is intended to upload images for manipulation.

Before:


	:::php
	if($file instanceof Image) {
		$upload = new UploadField();
		$upload->setAllowedFileCategories('image');
	}


After:


	:::php
	if($file->getIsImage()) {
		$upload = new UploadField();
		$upload->setAllowedFileCategories('image/supported');
	}


In cases where image-only assets may be assigned to relationships then your datamodel should specify explicitly
an `Image` datatype, or refer to `DBFile('image/supported')`.

E.g.


	:::php
	class MyObject extends DataObject {
		private static $has_one = array(
			"ImageObject" => "Image"
		);
		private static $db = array(
			"ImageField" => "DBFile('image/supported')"
		);
	}


### Upgrading code that writes to `File` dataobjects, or writes files to the 'assets' folder

In the past all that was necessary to write a `File` DataObject to the database was to ensure a physical file
existed in the assets folder, and that the Filename of the DataObject was set to the same location.

Since the storage of physical files is no longer a standard location, it's necessary to delegate the writing of such
files to the asset persistence layer. As a wrapper for an individual file, you can use any of the `setFrom*`
methods to assign content from a local (e.g. temporary) file, a stream, or a string of content.

You would need to upgrade your code as below.

Before:


	:::php
	function importTempFile($tmp) {
		copy($tmp, ASSETS_PATH . '/imported/' . basename($tmp));
		$file = new File();
		$file->setFilename('assets/imported/'.basename($tmp));
		$file->write();
	}


After:


	:::php
	function importTempFile($tmp) {
	    Versioned::reading_stage('Stage');
		$file = new File();
		$file->setFromLocalFile($tmp, 'imported/'.basename($tmp));
		$file->write();
		$file->doPublish();
	}


Note that 'assets' is no longer present in the new code, and the path beneath what was once assets is now
used to generate the 'filename' value. This is because there is no longer an assumption that files are
stored in the assets folder.

There are other important considerations in working with File dataobjects which differ from legacy:

* File synchronisation is no longer automatic. This is due to the fact that there is no longer a 1-to-1 relationship
  between physical files and File DataObjects.
* Folder DataObjects are now purely logical DataObjects, and perform no actual filesystem folder creation on write.
* All Files are versioned, which means that by default, new File records will not be visibile
  to the public site. You will need to make sure to invoke `->doPublish()` on any File DataObject
  you wish visitors to be able to see.

You can disable File versioning by adding the following to your _config.php


    :::php
    File::remove_extension('Versioned');


### Upgrading code performs custom image manipulations

As file storage and handling has been refactored into the abstract interface, many other components which were
once specific to Image.php have now been moved into a shared `ImageManipulation` trait. Manipulations of file content,
which are used to generate what are now called "variants" of assets, is now a generic api available to both `File`
and `DBFile` classes through this trait.

Custom manipulations, applied via extensions, must be modified to use the new API.

For instance, code which sizes images to a fixed width should be updated as below:

Before:


	:::php
	// in MyImageExtension.php
	class MyImageExtension extends DataExtension {
		public function GalleryThumbnail($height) {
			return $this->getFormattedImage('GalleryThumbnail', $height);
		}
		public function generateGalleryThumbnail(Image_Backend $backend, $height) {
			return $backend->paddedResize(300, $height);
		}
	}

	// in _config.php
	Image::add_extension('MyImageExtension');


Now image manipulations are implemented with a single method via a callback generator.

After:


	:::php
	// in MyImageExtension.php
	class MyImageExtension extends Extension {
		public function GalleryThumbnail($height) {
			// Generates the manipulation key
			$variant = $this->owner->variantName(__FUNCTION__, $height);

			// Instruct the backend to search for an existing variant with this key,
			// and include a callback used to generate this image if it doesn't exist
			return $this->owner->manipulateImage($variant, function(Image_Backend $backend) use ($height) {
				return $backend->paddedResize(300, $height);
			});
		}
	}

	// in _config.php
	File::add_extension('MyImageExtension');
	SilverStripe\Filesystem\Storage\DBFile::add_extension('MyImageExtension');


There are a few differences in this new API:

* The extension is no longer specific to DataObjects, so it uses the generic 'Extension' class instead of 'DataExtension'
* This extension is added to both `DBFile` and `File`, or order to make this manipulation available to non-dataobject
  file references as well, but it could be applied to either independently.
* A helper method `variantName` is invoked in order to help generate a unique variant key. Custom code may use another
  generation mechanism.
* Non-image files may also have manipulations, however the specific `manipulateImage` should not be used in this case.
  A generic `manipulate` method may be used, although the callback for this method both is given, and should return,
  an `AssetStore` instance and file tuple (Filename, Hash, and Variant) rather than an Image_Backend.

### Upgrading code that uses composite db fields.

The `CompositeDBField` interface has been replaced with an abstract class, `DBComposite`. In many cases, custom code
that handled saving of content into composite fields can be removed, as it is now handled by the base class.

The below describes the minimum amount of effort required to implement a composite DB field.

	:::php
	<?
	class MyAddressField extends DBComposite {

		private static $composite_db = array(
			'Street' => 'Varchar(200)',
			'Suburb' => 'Varchar(100)',
			'City' => 'Varchar(100)',
			'Country' => 'Varchar(100)'
		);

		public function scaffoldFormField($title = null) {
			new AddressFormField($this->getName(), $title);
		}
	}


### Upgrading code that references `DataObject::database_fields` or `DataObject::db`

These methods have been updated to include base fields (such as ID, ClassName, Created, and LastEdited), as
well as composite DB fields.

`DataObject::database_fields` does not have a second parameter anymore, and can be called directly on an object
or class. E.g. `Member::database_fields()`

If user code requires the list of fields excluding base fields, then use custom_database_fields instead, or
make sure to call `unset($fields['ID']);` if this field should be excluded.

`DataObject:db()` will return all logical fields, including foreign key ids and composite DB Fields, alongside
any child fields of these composites. This method can now take a second parameter $includesTable, which 
when set to true (with a field name as the first parameter), will also include the table prefix in
`Table.ClassName(args)` format.


### Update code that uses SQLQuery

SQLQuery is still implemented, but now extends the new SQLSelect class and has some methods
deprecated. Previously this class was used for both selecting and deleting, but these
have been superceded by the specialised SQLSelect and SQLDelete classes.

Take care for any code or functions which expect an object of type `SQLQuery`, as
these references should be replaced with `SQLSelect`. Legacy code which generates
`SQLQuery` can still communicate with new code that expects `SQLSelect` as it is a
subclass of `SQLSelect`, but the inverse is not true.

### Update implementations of augmentSQL

Since this method now takes a `SQLSelect` as a first parameter, existing code referencing the deprecated `SQLQuery`
type will raise a PHP error.

E.g.

Before:

	:::php
	function augmentSQL(SQLQuery &$query, DataQuery &$dataQuery = null) {
		$locale = Translatable::get_current_locale();
		if(!preg_match('/("|\'|`)Locale("|\'|`)/', implode(' ', $query->getWhere())))  {
			$qry = sprintf('"Locale" = \'%s\'', Convert::raw2sql($locale));
			$query->addWhere($qry); 
		}
	}

After:

	:::php
	function augmentSQL(SQLSelect $query, DataQuery $dataQuery = null) {
		$locale = Translatable::get_current_locale();
		if(!preg_match('/("|\'|`)Locale("|\'|`)/', implode(' ', $query->getWhereParameterised($parameters))))  {
			$query->addWhere(array(
				'"Locale"' => $locale
			));
		}
	}


### Update code that modifies the behaviour of ErrorPage

ErrorPage has been updated to use a configurable asset backend, similar to the `AssetStore` described above.
This replaces the `ErrorPage.static_filepath` config that was used to write local files.

As a result, error pages may be cached either to a local filesystem, or an external Flysystem store
(which is configured via setting a new Flysystem backend with YAML).

`ErrorPage::get_filepath_for_errorcode()` has been removed, because the local path for a specific code is
no longer assumed. Instead you should use `ErrorPage::get_content_for_errorcode` which retrieves the
appropriate content for that error using one of the methods above.

In order to retrieve the actual filename (which is used to identify an error page regardless of base
path), you can use `ErrorPage::get_error_filename()` instead. Unlike the old `get_filepath_for_errorcode`
method, there is no $locale parameter.

In case that user code must customise this filename, such as for extensions which provide a locale value
for any error page, the extension point `updateErrorFilename` can be used. This extension point should
also be used to replace any `alternateFilepathForErrorcode` used.

E.g.


	:::php
	class MyErrorPageExtension extends SiteTreeExtension {
		public function updateErrorFilename(&$name, &$statuscode) {
			if($this->owner->exists()) {
				$locale = $this->Locale;
			} else {
				$locale = Translatable::get_current_locale();
			}
			$name = "error-{$statusCode}-{$locale}.html";
		}
	}


	:::yaml
	ErrorPage:
	  extensions:
	    - MyErrorPageExtension

### Upgrading asset web.config, .htaccess, or other server configuration

Server configuration files for `/assets` are no longer static, and are regenerated via a set of
standard silverstripe templates on flush. These templates include:

 * `Assets_HTAccess.ss`: Template for public permissions on the Apache server.
 * `Assets_WebConfig.ss`: Template for public permissions on the IIS server.
 * `Protected_HTAccess.ss`: Template for the protected store on the Apache server (should deny all requests).
 * `Protected_WebConfig.ss`: Template for the protected store on the IIS server (should deny all requests).

You will need to make sure that these files are writable via the web server, and that any necessary
configuration customisation is done via overriding these templates.

If upgrading from an existing installation, make sure to invoke `?flush=all` at least once.

See [/developer_guides/files/file_security] for more information.

### `ListboxField` is now multiple-only

Previously, this field would operate as either a single select (default) or multi-select by setting
`setMultiple` to either true or false.

Now this field should only be used for multi-selection. Single-selection should be done using
a regular `DropdownField`.

### `GroupedDropdownField::setDisabled` now only accepts a list of values.

Where previously you could specify a list of grouped values in the same way as `setSource`, this
method now only accepts either a non-associative array of values (not titles) or an `SS_List`
of items to disable.

### Upgrading Requirements file paths

`Requirements` now throws an exception then a file is not found, rather than failing silently, so check your `Requirements` are pointing to files that exist.

Core JavaScript files paths have changed, so if you're referencing these, you'll have to update your file paths. Files previously in `admin/javascript` are now located in `admin/javascript/dist` and files previously located in `javascript` are now locatied in `javascript/dist`.

If you're not doing this already, we suggest looking into a JavaScript bundler like [Browserify](http://browserify.org/), to combine JavaScript files. SilverStripe core is moving away from `Requirements::combine_files` in favour of Browserify as of 4.0 and `Requirements::combine_files` is being considered for deprecation in future versions.

### Upgrading TinyMCE to 4.0

 Please see the [tinymce upgrading guide](http://archive.tinymce.com/wiki.php/Tutorial:Migration_guide_from_3.x)
 to assist with upgrades to customisations to tinymce 3.
 
 In Framework 4.0 the user interface for TinyMCE has been trimmed down considerably, with certain toolbar
 buttons removed from the default cms configuration. These include:
 * Strikethrough
 * Styles dropdown
 * Block quotes
 * Horizontal Rule
 * Undo / Redo
 * Cut / Paste as word
 * Select all
 * Fullscreen
 
However, these function may be enabled on a case by case basis through modifification of the default
tinymce config, or by creating custom configurations.

The optional `ss_macron` plugin for inserting Māori diacritical marks
has been removed from core. You can configure the built-in `charmap` plugin instead:
    
    :::php
    $editor = HtmlEditorConfig::get('cms');
    $editor->enablePlugins('charmap');
    $editor->addButtonsToLine(1, 'charmap');
    $editor->setOption('charmap_append', [
        ['256','A - macron'],
        ['274','E - macron'],
        ['298','I - macron'], 
        ['332','O - macron'], 
        ['362','U - macron'], 
        ['257','a - macron'], 
        ['275','e - macron'], 
        ['299','i - macron'], 
        ['333','o - macron'], 
        ['363','u - macron']
    ]);
 
For more information on available options and plugins please refer to the
[tinymce documentation](https://www.tinymce.com/docs/configure/)

### Upgrading DataObjects with the `Versioned` extension

In most cases, versioned models with the default versioning parameters will not need to be changed. However,
there are now additional restrictions on the use of custom stage names.

Rather than declaring the list of stages a model has, the constructor for `Versioned` will take a single mode
parameter, which declares whether or not the model is versioned and has a draft and live stage, or alternatively
if it only has versioning without staging.

For instance:


	:::php
	/**
	 * This model has staging and versioning. Stages will be "Stage" and "Live"
	 */
	class MyStagedModel extends DataObject {
		private staic $extensions = array(
			"Versioned('StagedVersioned')"
		);
	}
	
	/**
	 * This model has versioning only, and will not has a draft or live stage, nor be affected by the current stage.
	 */
	class MyVersionedModel extends DataObject {
		private static $extensions = array(
			"Versioned('Versioned')"
		);
	}


Additionally, the following api methods have been added:

 * `Versioned::publishRecursive` Publishes this object, and all owned objects
 * `Versioned::publishSingle` Publishes this object, but not owned objects
 * `Versioned::copyVersionToStage` Replaces the old `publish` method.
 
These methods are deprecated:

 * `Versioned::publish` Replaced by `Versioned::copyVersionToStage`
 * `Versioned::doPublish` Replaced by `Versioned::publishRecursive`

### Implementation of ownership API

In order to support the recursive publishing of dataobjects, a new API has been developed to allow
developers to declare dependencies between objects. See the
[versioned documentation](/developer_guides/model/versioning) for more information.

By default all versioned dataobjects will automatically publish objects that they own.

### ChangeSet batch publishing

ChangeSet objects have been added, which allow groups of objects to be published in
a single atomic transaction.

This API will utilise the ownership API to ensure that changes to any object include
all necessary changes to owners or owned entities within the same changeset.

### New `[image]` shortcode in `HTMLText` fields

The new Ownership API relies on relationships between objects.
Many of these relationships are already made explicit through `has_one`, `has_many` and `many_many`.
Images inserted into `HTMLText` fields (through a WYSIWYG editor) need to be tracked as well.
Instead of `<img>` tags, the field will insert `[image]` shortcodes which point to the database identifier
of the `Image` record rather than its path on the filesystem. The shortcode will be automatically replaced
when the field is rendered. Newly inserted images will automatically receive the shortcode and ownership tracking,
and existing `<img>` will continue to work.  

### Upgrading references to DBField and subclasses

A major change in 4.0 is the introduction of namespaced DBField subclasses. Now as a standard, all DBField subclasses have a `DB` prefix, are namespaced, and have an associative alias which omits the DB prefix.

This means that for the most part, code that worked in 3.0 won't need to be changed, although if you have any hard class literals which reference the old classes, they will need to be updated to point to the new namespaced classes.

An exception to this is any classes which once had the `SS_` prefix, which will now be instead prefixed with `DB`, and have an un-aliased prefix. For example `SS_Datetime` is now `DBDateTime`, and has the alias `DateTime` which may be used in config.

For example:

	class MyObject extends DataObject {
	    private static $db = array(
	        'Number' => 'Int',
	        'Time' => 'SS_Datetime'
	    );

	    /**
	     * @param Int $val
	     * @return Varchar
	     */
	    public function TextNumber() {
	        return new Varchar('TextNumber', 'Number is ' . $this->Number);
	    }
	}

Will become:

	use SilverStripe\Model\FieldType\DBVarchar;

	class MyObject extends DataObject {
	    private static $db = array(
	        'Number' => 'Int',
	        'Time' => 'Datetime'
	    );

	    /**
	     * @param Int $val
	     * @return Varchar
	     */
	    public function TextNumber() {
	        return new DBVarchar('TextNumber', 'Number is ' . $this->Number);
	    }
	}

Note that string references to SS_Datetime passed to injector, or used in config values, will still work, and will refer to the updated class names.