Introduce PartialRecursionDepthLimit

RoosterDragon commented 1 year ago

When evaluating templates with partials, it is possible to recurse in the evaluation of those partials. This can be useful for dealing with tree like data, such as rendering a list of friends-of-friends-of-friends-of-etc....

The ability to recurse can lead to stack overflows. For example if a sufficiently deep tree is provided as input data, or more simply if the partial calls itself in an infinite loop. As a stack overflow terminates the process, this is not desirable behaviour as it is an unavoidable crash.

To resolve this a configurable PartialRecursionDepthLimit is introduced, defaulting to 100. Now when a template is evaluated a HandlebarsRuntimeException will be thrown if this limit is reached. This allows the caller to catch the exception and recover gracefully, rather than terminating the process.