Extending custom groups to auto support new object

Steps currently required to make custom groups support a new object

Core And Custom Group Forms

• Fixing xml / schema to change enum for extends column of civicrm_custom_group table. File - xml/schema/Core/CustomGroup.xml.
• Fixing upgrade to address above schema change.
• Writing helper functions or CRM/{$Component}/PseudoConstant.php to generate types for new extend object. For example Contribution object has types as Donation, Event Fee etc.
• Adding to custom group extends list in CRM/Core/SelectValues::customGroupExtends().
• Adding "object -to-> table" mapping in CRM/Core/BAO/CustomGroup::mapTableName().
• Fixing custom group forms to list / populate / save new object and its types - CRM/Custom/Form/Group.php.
• Fixing display of custom groups extending new object in CRM/Custom/Page/Group.php

Injecting New Custom Fields In A Form And Supporting CRUD Operation

• Supporting CRUD operation for custom fields related to new object, for a form using -
  CRM_Custom_Form_Customdata::preProcess(),
  CRM_Custom_Form_Customdata::buildQuickForm(),
  CRM_Custom_Form_Customdata::setDefaultValues(),
  CRM_Core_BAO_CustomField::postProcess() to format the custom fields in proper format.
• If your new object has a BAO file example CRM/$Object/BAO$Object.php, the create file in same function should be made responsible for saving custom field values (if any) with the help of CRM_Core_BAO_CustomValueTable::store() method.
• Fixing form tpl to inject CRM/Custom/Form/CustomData.tpl and js file CRM/common/customData.tpl.

Adding Support To Searches

• If there is a component advanced search pane in advanced search that you would like your custom fields rendered into, CRM/{$Component}/Form/Search.php is the file generally, where you could add support for injecting / building custom field forms.
• If a component search is to be populated with custom fields related to new object, CRM/{$Component}/Form/Search{$component}.php is generally the file, you would be adding support to.
• Make sure CRM/{$Component}/BAO/Query.php for new object supports querying custom fields.

Adding Support To Profiles

• Fixing profile form to list custom fields corresponding to related object in CRM/UF/Form/Field.php.
• If required making sure profile supports add / update / view of these custom fields.

Adding Support To Import / Export

• Fixing import / export to reflect fields for this new custom object.
• Needs more investigation ...

Suggestions To Make Custom Fields Auto Support A New Object

Core And Custom Group Forms

• Remove enum constraint from extends column of custom_group table. Make it a varchar.
• Store the custom group extends list along with types for every object, and entity_table (for object to table mapping) in option_group / value table.
• Fixing CRM/Core/SelectValues::customGroupExtends() method to retrieve 'custom group extends' list from option group / value table.
• Fixing CRM/Custom/Form/Group.php (and page) to retrieve type list from option group / value table.
• Fixing custom group schema handler to look for object to table mapping in option group / value table.