Péter Kovács opened SPR-12607 and commented
In practice the context-relative attribute on an mvc:redirect-view-controller element defaults to "false" when it's not set.
For example <mvc:redirect-view-controller path="/a" redirect-url="/b" /> will create a controller that redirects from http://localhost:8080/context/a to http://localhost:8080/b.
This contradicts the description of the attribute (from spring-mvc-4.1.xsd):
Whether to interpret a given redirect URL that starts with a slash ("/") as relative to the current ServletContext, i.e. as relative to the web application root. The default is "true".
Affects: 4.1.4
Referenced from: commits 3da9d92, 0c8d07f