Backwards Compatibility ¶
We're strictly not breaking backwards compatibility in patch releases such as 2.x.y.Z and trying to avoid had to fix
backwards incompatible changes in minor releases such as 2.x.Y.
Check Yii Versioning to learn about version numbering.
Usage ¶ Interfaces ¶
Use case BC?
Type hint with the interface Yes Call the interface method Yes Implement the interface and... Implement method Yes Add argument to method implemented Yes Add default value to an argument Yes
Classes ¶
Use case BC?
Type hint with the class Yes Create a new instance Yes Extend the class Yes Access a public property Yes Call a public method Yes Extend the class and... Access a protected property Yes Call a protected method Yes Override a public property Yes Override a protected property Yes Override a public method Yes Override a protected method Yes Add a new property No Add a new method No Add an argument to an overridden method Yes Add a default value to an argument Yes Call a private method (via Reflection) No Access a private property (via Reflection) No
Development ¶ Changing interfaces ¶
Type of change BC?
Remove No Change name or namespace No Add parent interface Yes if no new methods are added Remove parent interface No Interface methods Add method No Remove method No Change name No Move to parent interface Yes Add argument without a default value No Add argument with a default value No Remove argument Yes (only last ones) Add default value to an argument No Remove default value of an argument No Add type hint to an argument No Remove type hint of an argument No Change argument type No Change return type No Constants Add constant Yes Remove constant No Change value of a constant Yes except objects that are likely to be serialized. Mandatory to document in UPGRADE.md.
Classes ¶
Type of change BC?
Remove No Make final No Make abstract No Change name or namespace No Change parent class Yes but original parent class must remain an ancestor of the class. Add interface Yes Remove interface No Public Properties Add public property Yes Remove public property No Reduce visibility No Move to parent class Yes Protected Properties Add protected property Yes Remove protected property No Reduce visibility No Move to parent class Yes Private Properties Add private property Yes Remove private property Yes Constructors Remove constructor No Reduce visibility of a public constructor No Reduce visibility of a protected constructor No Move to parent class Yes Public Methods Add public method Yes Remove public method No Change name No Reduce visibility No Move to parent class Yes Add argument without a default value No Add argument with a default value No Remove arguments Yes, only last ones Add default value to an argument No Remove default value of an argument No Add type hint to an argument No Remove type hint of an argument No Change argument type No Change return type No Protected Methods Add protected method Yes Remove protected method No Change name No Reduce visibility No Move to parent class Yes Add argument without a default value No Add argument with a default value No Remove arguments Yes, only last ones Add default value to an argument No Remove default value of an argument No Add type hint to an argument No Remove type hint of an argument No Change argument type No Change return type No Private Methods Add private method Yes Remove private method Yes Change name Yes Add argument without a default value Yes Add argument with a default value Yes Remove argument Yes Add default value to an argument Yes Remove default value of an argument Yes Add type hint to an argument Yes Remove type hint of an argument Yes Change argument type Yes Change return type Yes Static Methods Turn non static into static No Turn static into non static No Constants Add constant Yes Remove constant No Change value of a constant Yes except objects that are likely to be serialized. Mandatory to document in UPGRADE.md.