What causes "the rebase state contains duplicate scope commits" in GitoxideLabs/gitoxide?

Deduplicate `scope` lines in the state file so each commit OID appears once.

the rebase state contains duplicate scope commits

Error message

the rebase state contains duplicate scope commits

What it means

During state validation, `validate_state` collects all `scope` OIDs into a `HashSet` and compares its size against the original vector. A size mismatch means the same commit OID was listed in `scope` more than once; since scope membership is a set concept, duplicates indicate a malformed state and validation aborts.

Solutions

Deduplicate `scope` lines in the state file so each commit OID appears once.
Regenerate the state by restarting the rebase/edit operation.
Fix any automation that builds the scope list to deduplicate OIDs before writing.

Example fix

// before (state file)
scope 0123abc...
scope 0123abc...
// after
scope 0123abc...

Defensive patterns

Strategy: validation

Validate before calling

fn scope_lines_are_unique(text: &str) -> bool {
    let ids: Vec<&str> = text.lines()
        .filter_map(|l| l.strip_prefix("scope "))
        .collect();
    ids.iter().collect::<std::collections::HashSet<_>>().len() == ids.len()
}

Try / catch

match todo::parse(state_text) {
    Ok(state) => apply(state),
    Err(e) if e.to_string().contains("duplicate scope commits") => {
        eprintln!("deduplicate scope lines before parsing");
    }
    Err(e) => return Err(e),
}

Prevention

Deduplicate OIDs before writing scope lines in generated state.
Use a set-based collector when building the scope list.
Round-trip validate generated state (write then parse) in tests.

When it happens

Trigger: `parse_state` (via validate_state, gix-tix/src/edit/todo.rs:782) parses a state file where two or more `scope <oid>` lines repeat the same commit OID.

Common situations: Hand-edited state duplicating a scope entry; scripts appending scope commits without deduplication; merged state files from divergent sessions.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of GitoxideLabs/gitoxide@e73179060b (2026-09-08). Data as JSON: /api/errors/67111b15d6c84131. Report an issue: GitHub.

Appendix: source

Thrown at gix-tix/src/edit/todo.rs:782

        head_ref,
        edit_refs,
        expected_refs,
        resolved,
        continuation_sources,
    };
    validate_state(repo, &state)?;
    Ok(Some(state))
}

fn validate_state(repo: &gix::Repository, state: &State) -> Result<()> {
    repo.find_commit(state.base)
        .context("could not find the recorded rebase base")?;
    repo.find_commit(state.onto)
        .context("could not find the recorded rebase target")?;
    let scope: HashSet<_> = state.scope.iter().copied().collect();
    let continuation_sources: HashSet<_> = state.continuation_sources.iter().copied().collect();
    if scope.len() != state.scope.len() {
        anyhow::bail!("the rebase state contains duplicate scope commits");
    }
    if state.tips.iter().copied().collect::<HashSet<_>>().len() != state.tips.len() {
        anyhow::bail!("the rebase state contains duplicate tips");
    }
    let mut refs = HashSet::new();
    for reference in &state.expected_refs {
        if !refs.insert(reference.name.as_bstr()) {
            anyhow::bail!("the rebase state contains duplicate refs");
        }
        if !scope.contains(&reference.target) && reference.target != state.base && reference.target != state.onto {
            anyhow::bail!("a captured ref does not logically point into the rebase scope");
        }
    }
    if let Some(name) = &state.head_ref
        && !state
            .expected_refs
            .iter()
            .any(|reference| reference.editable && reference.name == *name)

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