Panic when using `gix::config::File::remove_section_filter`

[emilazy]

Current behavior 😯

Trying to iteratively remove subsections with a filter matching the metadata against the loaded repository configuration file’s metadata seems to panic.

Expected behavior 🤔

When running the provided test program, the [remote "origin"] sections that come from the loaded configuration file should be removed.

Git behavior

Presumably git config handles this properly :)

Steps to reproduce 🕹

yuyuko:~/Developer/gix-remote-bug  (no description set)
❭ cat src/main.rs
use std::{fs::File, sync::Arc};

use gix::bstr::BStr;
use tempfile::TempDir;

type Error = Box<dyn std::error::Error>;

fn set_up_repository(repo_dir: &TempDir) -> Result<(), Error> {
    let repo = gix::init(repo_dir)?;
    let mut config = repo.config_snapshot().clone();
    let config_meta = Arc::unwrap_or_clone(config.meta_owned());
    repo.remote_at("https://example.com/")?
        .save_as_to("origin", &mut config)?;
    let mut config_file = File::create(config_meta.path.clone().unwrap())?;
    config.write_to_filter(&mut config_file, |section| section.meta() == &config_meta)?;
    Ok(())
}

fn demonstrate_bug(repo_dir: TempDir) -> Result<(), Error> {
    let repo = gix::open(repo_dir.into_path())?;
    let mut config = repo.config_snapshot().clone();
    let config_meta = Arc::unwrap_or_clone(config.meta_owned());
    while config
        .remove_section_filter("remote", Some(BStr::new("origin")), |meta| {
            meta == &config_meta
        })
        .is_some()
    {}
    Ok(())
}

fn main() -> Result<(), Error> {
    let repo_dir = tempfile::tempdir()?;
    set_up_repository(&repo_dir)?;
    demonstrate_bug(repo_dir)?;
    Ok(())
}

yuyuko:~/Developer/gix-remote-bug  (no description set)
❭ cargo run
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.51s
     Running `target/debug/gix-remote-bug`

thread 'main' panicked at /Users/emily/.cache/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/gix-config-0.43.0/src/file/access/mutate.rs:308:53:
each id has a section
stack backtrace:
   0: rust_begin_unwind
             at /rustc/99768c80a1c094a5cfc3b25a04e7a99de7210eae/library/std/src/panicking.rs:695:5
   1: core::panicking::panic_fmt
             at /rustc/99768c80a1c094a5cfc3b25a04e7a99de7210eae/library/core/src/panicking.rs:75:14
   2: core::panicking::panic_display
             at /rustc/99768c80a1c094a5cfc3b25a04e7a99de7210eae/library/core/src/panicking.rs:261:5
   3: core::option::expect_failed
             at /rustc/99768c80a1c094a5cfc3b25a04e7a99de7210eae/library/core/src/option.rs:2024:5
   4: core::option::Option<T>::expect
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/option.rs:933:21
   5: gix_config::file::access::mutate::<impl gix_config::types::File>::remove_section_filter_inner::{{closure}}
             at /Users/emily/.cache/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/gix-config-0.43.0/src/file/access/mutate.rs:308:31
   6: core::iter::traits::double_ended::DoubleEndedIterator::rfind::check::{{closure}}
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/iter/traits/double_ended.rs:364:20
   7: core::iter::adapters::copied::copy_try_fold::{{closure}}
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/iter/adapters/copied.rs:34:22
   8: core::iter::traits::double_ended::DoubleEndedIterator::try_rfold
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/iter/traits/double_ended.rs:238:21
   9: <core::iter::adapters::copied::Copied<I> as core::iter::traits::double_ended::DoubleEndedIterator>::try_rfold
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/iter/adapters/copied.rs:121:9
  10: core::iter::traits::double_ended::DoubleEndedIterator::rfind
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/iter/traits/double_ended.rs:368:9
  11: <core::iter::adapters::rev::Rev<I> as core::iter::traits::iterator::Iterator>::find
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/iter/adapters/rev.rs:72:9
  12: gix_config::file::access::mutate::<impl gix_config::types::File>::remove_section_filter_inner
             at /Users/emily/.cache/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/gix-config-0.43.0/src/file/access/mutate.rs:304:18
  13: gix_config::file::access::mutate::<impl gix_config::types::File>::remove_section_filter
             at /Users/emily/.cache/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/gix-config-0.43.0/src/file/access/mutate.rs:295:9
  14: gix_remote_bug::demonstrate_bug
             at ./src/main.rs:23:11
  15: gix_remote_bug::main
             at ./src/main.rs:35:5
  16: core::ops::function::FnOnce::call_once
             at /nix/store/3zf4srnn9sc5hm7jk4g13kkmrc2jf39n-rust-default-1.86.0-nightly-2025-01-24/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[Byron]

Thanks for reporting and for providing a reproduction, and sorry for the late reply!
I hope to have it fixed soon.