[![Crate][CrateStatus]][Crate]
[![Tests][TestsStatus]][Tests]
[![Docs][PagesStatus]][Docs]

# bare\_err\_tree
`bare_err_tree` is a `no_std` library to print a standard `Error` with a tree of sources.

Support for the extra information prints does not change the type or public API (besides a hidden field or deref).
It is added via macro or manual implementation of the `AsErrTree` trait (see
the [docs][Docs] for details).
End users can then use `tree_unwrap` or `print_tree` to get better error output.

Unlike [anyhow][Anyhow], [eyre][Eyre], or [error-stack][ErrorStack], the extra
functionality does not require exposing a special type in a library's API.
A library can use `bare_err_tree` for its errors without changing any types,
and library users can ignore the the existence of this crate entirely. There is
also support for including any implementor of `Error` in the tree with less
information, so it works on top of std and other libraries.

The formatting is borrowed from from [error-stack][ErrorStack].
Please see the [contributors page](https://github.com/hashintel/hash/graphs/contributors) for appropriate credit.

# Example Output (source\_line)
Generate with `cd testing; cargo run --bin example`.
```
missed class
├─ at testing/src/bin/example.rs:25:6
│
╰─▶ stayed in bed too long
    ├─ at testing/src/bin/example.rs:17:57
    │
    ├─▶ bed is comfortable
    │
    ╰─▶ went to sleep at 2 A.M.
        ├─ at testing/src/bin/example.rs:17:72
        │
        ├─▶ finishing a project
        │   │
        │   ╰─▶ proving 1 == 2
        │
        ├─▶ stressed about exams
        │
        ╰─▶ playing video games
```

# Example Output (source\_line + tracing)
Generate with `cd testing_trace; cargo run --bin trace_example`.
```
missed class
├─ at testing_trace/src/bin/trace_example.rs:44:6
│
├─ tracing frame 0 => trace_example::run_fatal
│        at testing_trace/src/bin/trace_example.rs:31
│
╰─▶ stayed in bed too long
    ├─ at testing_trace/src/bin/trace_example.rs:33:57
    │
    ├─ tracing frame 1 => trace_example::new with
    │    bed_time=BedTime {
    │      hour: 2,
    │      reasons: [
    │        FinishingProject(
    │          ClassProject {
    │            desc: "proving 1 == 2"
    │          }
    │        ),
    │        ExamStressed,
    │        PlayingGames
    │      ]
    │    }
    │    _garbage=5
    │        at testing_trace/src/bin/trace_example.rs:117
    ├─ 1 duplicate tracing frame(s): [0]
    │
    ├─▶ bed is comfortable
    │
    ╰─▶ went to sleep at 2 A.M.
        ├─ at testing_trace/src/bin/trace_example.rs:34:9
        │
        ├─ 1 duplicate tracing frame(s): [0]
        │
        ├─▶ finishing a project
        │   │
        │   ╰─▶ proving 1 == 2
        │
        ├─▶ stressed about exams
        │
        ╰─▶ playing video games
```

# TODO
* Clean up proc macro code
    * Add more internal documentation
    * Write tests to make sure the proc macro is fully correct

[CrateStatus]: https://img.shields.io/crates/v/bare_err_tree.svg
[Crate]: https://crates.io/crates/bare_err_tree
[TestsStatus]: https://github.com/Bennett-Petzold/bare_err_tree/actions/workflows/all-tests.yml/badge.svg?branch=main
[Tests]: https://github.com/Bennett-Petzold/bare_err_tree/actions/workflows/all-tests.yml
[PagesStatus]: https://github.com/Bennett-Petzold/bare_err_tree/actions/workflows/pages.yml/badge.svg?branch=main
[Docs]: https://bennett-petzold.github.io/bare_err_tree/docs/bare_err_tree/
[Coverage]: https://bennett-petzold.github.io/bare_err_tree/coverage/badge.svg
[CoveragePages]: https://bennett-petzold.github.io/bare_err_tree/coverage/

[ErrorStack]: https://crates.io/crates/error-stack
[Eyre]: https://crates.io/crates/eyre
[Anyhow]: https://crates.io/crates/anyhow