pub fn try_lookup_int(key: &str) -> Option<i64>Expand description
lookup_int variant that never panics on a live mutable borrow.
Returns None when STATE is currently mutably borrowed (contention),
Some(0) when the key is absent/non-integer (matching lookup_int’s
default), else Some(value).
This exists for the Error!/Warn! reporting path: an error can legitimately
be raised from inside a state_mut() scope (e.g. push_value’s BUG branch,
or any constructor after_digest holding the borrow). A plain borrow() there
panics “RefCell already mutably borrowed”, aborting the whole conversion
(FATAL_panic; crashed tikz-cd 2001.08973 via push_value("QED@stack", …)).
The error reporter must be re-entrancy-safe regardless of what borrows are
held — degrade to “unknown” on contention rather than crash.