Debug Assertions Triggered In gix-blame

[holodorum]

Current behavior 😯

Last week I was playing around with gix blame recently upgraded by @cruessler.
I've made a clone of the linux repository and ran the following script to get the blame for CREDITS.

use gitoxide_core::repository::blame::blame_file;

fn main() -> anyhow::Result<()> {
    // Set repository and file to read
    let repo = gix::discover("./tmp/linux/").unwrap();
    let file = OsStr::new("CREDITS");

    let out = std::fs::File::create("./tmp/out.txt")?;
    blame_file(repo, file, None, &mut std::io::BufWriter::new(out), Some(&mut std::io::stdout()))?;

    Ok(())
}

The program hits one of the debug assertions with the following output:

❯ RUST_BACKTRACE=1 cargo run --bin bug_blame
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.30s
     Running `target/debug/bug_blame`
thread 'main' panicked at /xxxxx/gitoxide/gix-blame/src/file/function.rs:301:25:
#[
    UnblamedHunk {
        range_in_blamed_file: 0..22,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 0..22,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 26..191,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 22..187,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 196..282,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 187..273,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 282..389,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 273..380,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 392..544,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 380..532,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 551..585,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 532..566,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 588..820,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 566..798,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 825..1218,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 798..1191,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1222..1247,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1191..1216,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1251..1376,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1216..1341,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1376..1434,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1345..1403,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1438..1695,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1403..1660,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1695..1709,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1665..1679,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1714..1822,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1679..1787,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1826..1893,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1787..1854,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1897..1898,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1854..1855,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 1901..2213,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 1855..2167,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 2213..3181,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 2180..3148,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 3187..3204,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 3148..3165,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 3209..3317,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 3165..3273,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 3321..3598,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 3273..3550,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 3598..3787,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 3555..3744,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 3792..3817,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 3744..3769,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 3821..4311,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 3769..4259,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 4315..4415,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 4259..4359,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 4415..4416,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 4359..4360,
        },
    },
    UnblamedHunk {
        range_in_blamed_file: 4419..4464,
        suspects: {
            Sha1(4cece764965020c22cff7665b18a012006359095): 4359..4404,
        },
    },
]
stack backtrace:
   0: rust_begin_unwind
             at /rustc/e71f9a9a98b0faf423844bf0ba7438f29dc27d58/library/std/src/panicking.rs:665:5
   1: core::panicking::panic_fmt
             at /rustc/e71f9a9a98b0faf423844bf0ba7438f29dc27d58/library/core/src/panicking.rs:76:14
   2: gix_blame::file::function::file
             at ./gix-blame/src/file/function.rs:301:25
   3: gitoxide_core::repository::blame::blame_file
             at ./gitoxide-core/src/repository/blame.rs:41:19
   4: bug_blame::main
             at ./src/bin/bug_blame.rs:11:5
   5: core::ops::function::FnOnce::call_once
             at /xxx/.rustup/toolchains/stable-aarch64-apple-darwin/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.

Expected behavior 🤔

Running the same code on the README file returns without errors.

Git behavior

No response

Steps to reproduce 🕹

No response

[cruessler]

@holodorum Thanks a lot for the report and the detailed reproduction! I’ll have a look! (Context: I know that there are edge cases that the graph traversal algorithm used by gix-blame does not handle well. So far, I haven’t been able to find the root cause for these errors, so this report is very helpful!)