Project cascading

The concept of cascading project is the ability to inherit project properties from parent in a cascading fashion down the inheritance tree as  discussed in HUDSON-3157 Feature request: cascading project settings.  

Initially  the implementation will be kept simple, with only few UI changes

• Drop down Box at the top of the project config page to select one the saved project to inherit from (filtered by the same type)
  
• Any project of same type can be used as a parent project for inheritance
• Cycle inheritance is prohibited. The dropdown will not have those projects which can make potential cyclic dependency.
• All Job properties will be shown on the Configure Page, by default they will be taken from Parent
• User can override configuration properties by changing them on Child Configuration Page. When overiiden, property will be highlighted to show it is overriden

• User will be allowed to revert the overriding property to that of the parent using a simple revert button at the left hand side
  

• User will not be allowed to delete the project, if the it has cascading children
  

• If Parent contains Builders, Publishers or Triggers they will be merged with Child.

Project properties which support cascading in 2.2.0-BETA2 (Released on Nov 15, 2011)

Project properties which support cascading in 2.2.0-BETA (Released Oct 26, 2011)

Hudson plugins which support cascading

Implementation Point of View

• Parent project is a regular project.
• Additional property will be added to the regular project to hold the "Cascading parent name"
• The inheritance will be done purely by comparison.
• Same way initially the loading and saving of config page is also done purely by comparison.
  • All the UI elements in the config page relies on respective getter method of the project. The getter will provide corresponding data comparing what is saved in the project level config and what is saved in the parent level.
  • While saving, compare project level and parent level. If the item (property) to be saved match that of the parent, do not save it in the project config, keep it in the parent config. Properties can have multiple count (example: a project can have more than one builder), So while comparing the count also should be taken in to consideration.