Miette panic handler missing lines

[sophiajt]

Noticed that sometimes miette is missing lines in the panic when you use Miette's custom handler.

Here's one example:

Miette:

  × Main thread panicked.
  ├─▶ at crates/nu-protocol/src/engine/stack.rs:46:9
  ╰─▶ variable not found
         0: 0x56147c2f1d38 - engine_q::main::h85b5921abc527ed0
                      at /home/jt/Source/engine-q/src/main.rs:185
         1: 0x56147c2ecf9b -
      core::ops::function::FnOnce::call_once::h70b5d4743a54f260
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/core/src/ops/function.rs:227
         2: 0x56147c2e701e -
      std::sys_common::backtrace::__rust_begin_short_backtrace::h9da7e7484d516
      5ac
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/sys_common/backtrace.rs:123
         3: 0x56147c2ee141 - std::rt::lang_start::
      {{closure}}::hc474539033f905d0
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/rt.rs:145
         4: 0x56147ce4f181 - core::ops::function::impls::<impl
      core::ops::function::FnOnce<A> for &F>::call_once::h42d3791e66d196c0
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/core/src/ops/function.rs:259
                       - std::panicking::try::do_call::hc3bcb188e535517f
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
            at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/panicking.rs:406
                       - std::panicking::try::hb1edf04d4a7097ab
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/panicking.rs:370
                       - std::panic::catch_unwind::h75ed941ac0d36d57
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/panic.rs:133
                       - std::rt::lang_start_internal::
      {{closure}}::hc702b3389af4cbea
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/rt.rs:128
                       - std::panicking::try::do_call::h53276a03c7fe2ebc
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/panicking.rs:406
                       - std::panicking::try::ha9e37f45dc542517
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/panicking.rs:370
                       - std::panic::catch_unwind::h182647595766fee7
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/panic.rs:133
                       - std::rt::lang_start_internal::h571831ebdba142de
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/rt.rs:128
         5: 0x56147c2ee110 - std::rt::lang_start::h58c5b562df81656b
                      at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/
      library/std/src/rt.rs:144
         6: 0x56147c2f5f5c - main
         7: 0x7fe5016fa0b3 - __libc_start_main
         8: 0x56147c2e5f4e - _start
         9:        0x0 - <unresolved>

Compared to:

   0: std::panicking::begin_panic
             at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/library/std/src/panicking.rs:525:12
   1: nu_protocol::engine::stack::Stack::get_var
             at ./crates/nu-protocol/src/engine/stack.rs:46:9
   2: nu_protocol::engine::stack::Stack::get_config
             at ./crates/nu-protocol/src/engine/stack.rs:89:22
   3: <nu_command::viewers::table::Table as nu_protocol::engine::command::Command>::run
             at ./crates/nu-command/src/viewers/table.rs:35:22
   4: engine_q::print_value
             at ./src/main.rs:286:25
   5: engine_q::eval_source
             at ./src/main.rs:389:31
   6: engine_q::main
             at ./src/main.rs:185:21
   7: core::ops::function::FnOnce::call_once
             at /rustc/936238a92b2f9d6e7afe7dda69b4afd903f96399/library/core/src/ops/function.rs:227:5

Miette has more lines, but the rustc panic handler shows more of the lines that happened inside of the user code. I've seen this in both stable and nightly rustc.

[zkat]

The code for this is here: https://github.com/zkat/miette/blob/main/src/panic.rs#L37-L86

I wonder what's going on. It sure looks like miette is just skipping over most of the user code here. :(