Deprecation: #65290 - TCA changes 

Simplified types showitem configuration using columnsOverrides 

If a field is configured as type in TCA ctrl section, the value of this database field determines which fields are shown if opening a record in the backend. The shown fields are configured in TCA section types showitem and is a comma separated list of field names. Each field name can have 4 additional semicolon separated options, from which the last two have been dropped and moved:

Before:

'types' => array(
	'aType' => array(
		'showitem' => 'aField,anotherField;otherLabel;aPalette;special:configuration;a-style-indicator,thirdField',
	),
),

If a record is opened that has the type field set to aType, it would show the three fields aField, anotherField and thirdField. The second field anotherField has further configuration and shows a different label, adds an additional palette below the field referenced as aPalette, adds special:configuration as special configuration and changes the style with its last field. The last two parameters were changed: The style configuration is obsolete since 7.1 and has been removed. The special configuration is identical to the defaultExtras field of a columns field section and can be added with this name in a newly introduced array columnsOverrides that is parallel to showitem of this type:

'types' => array(
	'aType' => array(
		'showitem' => 'aField,anotherField;otherLabel;aPalette,thirdField',
		'columnsOverrides` => array(
			'anotherField' => array(
				'defaultExtras' => 'special:configuration',
			),
		),
	),
),

So, the 4th parameter has been transferred to columnsOverrides while the 5th parameter has been removed.

This change enables more flexible overrides of column configuration based on a given type. This is currently used in FormEngine only, so only view-related parameters must be overwritten here. It is not supported to change data handling related parameters like type=text to type=select or similar, but it is possible to change for example the number of rows shown in a type=text column field:

'types' => array(
	'aType' => array(
		'showitem' => 'aField,anotherField;otherLabel;aPalette,thirdField',
		'columnsOverrides` => array(
			'anotherField' => array(
				'config' => array(
					'rows' => 42,
				),
			),
		),
	),
),

It is also possible to remove a given configuration from the default configuration using the __UNSET keyword. Again, this is only supported for view-related configuration options. Changing for instance an eval option may cripple the PHP-side validation done by the DataHandler that checks and stores values.

'types' => array(
	'aType' => array(
		'columnsOverrides` => array(
			'bodytext' => array(
				'config' => array(
					'rows' => '__UNSET',
				),
			),
		),
	),
),

The above example would remove the rows parameter of the bodytext field columns configuration, so a default value would be used instead.

Simplified t3editor configuration 

t3editor is no longer configured and enabled as wizard.

Configuration for a column field looked like this before:

'bodytext' => array(
	'config' => array(
		'type' => 'text',
		'rows' => 42,
		'wizards' => array(
			't3editor' => array(
				'type' => 'userFunc',
				'userFunc' => 'TYPO3\CMS\T3editor\FormWizard->main',
				'title' => 't3editor',
				'icon' => 'wizard_table.gif',
				'module' => array(
					'name' => 'wizard_table'
				),
				'params' => array(
					'format' => 'html',
					'style' => 'width:98%; height: 60%;'
				),
			),
		),
	),
),

The new configuration is simplified to:

'bodytext' => array(
	'exclude' => 1,
	'label' => 'aLabel',
	'config' => array(
		'type' => 'text',
		'renderType' => 't3editor',
		'format' => 'html',
		'rows' => 42,
	),
),

In case t3editor was only enabled for a specific type, this was previously done with enableByTypeConfig within the wizard configuration and wizards[theWizardName] as the 4th semicolon separated parameter of the according field in section showitem of the type where t3editor should be enabled. Old configuration was:

'columns' => array(
	'bodytext' => array(
		'exclude' => 1,
		'label' => 'aLabel',
		'config' => array(
			'type' => 'text',
			'rows' => 42,
			'wizards' => array(
				't3editorHtml' => array(
					'type' => 'userFunc',
					'userFunc' => 'TYPO3\CMS\T3editor\FormWizard->main',
					'enableByTypeConfig' => 1,
					'title' => 't3editor',
					'icon' => 'wizard_table.gif',
					'module' => array(
						'name' => 'wizard_table'
					),
					'params' => array(
						'format' => 'html',
						'style' => 'width:98%; height: 60%;'
					),
				),
			),
		),
	),
),
'types' => array(
	'firstType' => array(
		'showitem' => 'bodytext;;;wizards[t3editorHtml]',
	),
),

This now uses the new columnsOverrides feature parallel to showitem:

'columns' => array(
	'bodytext' => array(
		'config' => array(
			'type' => 'text',
			'rows' => 42,
		),
	),
),
'types' => array(
	'firstType' => array(
		'showitem' => 'bodytext',
		'columnsOverrides' => array(
			'bodytext' => array(
				'config' => array(
					'format' => 'typoscript',
					'renderType' => 't3editor',
				),
			),
		),
	),