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Maximum Size of Arrays
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Limit How Large Arrays Can Grow
Rhai by default does not limit how large an [array] can be.
This can be changed via the Engine::set_max_array_size method, with zero being unlimited (the default).
A script attempting to create an array literal larger than the maximum will terminate with a parse error.
Any script operation that produces an array larger than the maximum also terminates the script with an error result.
This check can be disabled via the [unchecked] feature for higher performance (but higher risks as well).
let mut engine = Engine::new();
engine.set_max_array_size(500); // allow arrays only up to 500 items
engine.set_max_array_size(0); // allow unlimited arrays
Setting Maximum Size
Be conservative when setting a maximum limit and always consider the fact that a registered function may grow an array's size without Rhai noticing until the very end.
For instance, the built-in '+' operator for arrays concatenates two arrays together to form one larger array;
if both arrays are slightly below the maximum size limit, the resultant array may be almost twice the maximum size.
As a malicious script may create a deeply-nested array which consumes huge amounts of memory while each individual array still stays under the maximum size limit, Rhai also recursively adds up the sizes of all [strings], [arrays] and [object maps] contained within each array to make sure that the aggregate sizes of none of these data structures exceed their respective maximum size limits (if any).