Struct Nesting 

pub struct Nesting { /* private fields */ }

A recursion counter, held by whatever is recursing.

The discipline is enter at the recursion site and leave on the way out — at the site, not at one grammar rule that seemed to be where nesting comes from. That is the Scriban lesson (GHSA-p6q4-fgr8-vx4p, §42.2): a limit added at the one production somebody thought of was bypassed through a different one.

Implementations

impl Nesting

pub fn new() -> Nesting

pub fn with_limit(limit: u32) -> Nesting

A counter with a lower ceiling, for a test that would rather not build a 256-deep input.

pub fn resumed(&self) -> Nesting

A counter for a sub-parse that continues this one, starting at the depth already reached.

A sub-parser over a captured token run is still inside whatever brackets captured it, and a counter that started again at zero would be a way in — the same shape of bypass the Scriban advisory records.

pub fn limit(&self) -> u32

pub fn depth(&self) -> u32

pub fn enter(&mut self) -> bool

Descend one level. false means the ceiling is reached and the caller must not recurse — and must not leave either, because nothing was entered.

pub fn leave(&mut self)

pub fn should_report(&mut self) -> bool

True exactly once per compilation.

One over-deep expression is refused at every level on the way out, and a reader wants the count, not one copy of it per level.

pub fn note(&self) -> String

The note every site prints, so the three of them say the same thing.

pub fn note_about(&self, what: &str) -> String

The same note, naming the axis being counted.

Two axes reach the same stack — nesting depth and the length of a flat chain (MAX_BLOCK) — and a note that called the second “nesting” would send a reader looking for brackets in a function that has none.

Trait Implementations

impl Debug for Nesting

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Nesting

fn default() -> Nesting

Returns the “default value” for a type.