Call Compatibility

A component is call compatible with another component if uses of the first component can be safely replaced with uses of the other in these cases:

• When making a call to a <control>, <uninstall>, or <snapshot> block of the first component

• When checking for dependencies of the first component by using <checkDependency> or <createDependency>

• When referring to a variable of the first component, by using configuration generation :[component:AB:var]

Call compatibility is also known as API compatibility or interface compatiblity.

Usually, two call-compatible components are different versions of a component that are in the same version tree. However, the second component can also be in a distinct version tree if it is an instance of the first component.

The N1 SPS product enforces call compatibility for components that provide system services. When a system service is updated to refer to a new component, the new component must be call compatible with the original component. This policy ensures that clients of the system service can continue to function properly when the system service is upgraded.

The N1 SPS product also optionally verifies call compatibility when it resolves components that are referenced by certain installed component targeters. See Installed Component Targeters.

Though not required, ensure that a component is call compatible with earlier versions of itself.