Hmbown/CodeWhale · error · anyhow::Error

Complete local diff requires

Error message

Complete local diff requires {chars} characters, exceeding the review limit of {max_chars}. No review was run and no receipt was written or accepted. Select an explicit --path scope, or increase --max-chars only if the selected model can accept the complete input.

What it means

Before sending a complete local diff for review, the code counts its characters and refuses to proceed if it exceeds the configured --max-chars limit. This is a deliberate guard: no model request is made and no review receipt is written or accepted when the diff is truncated implicitly.

Solutions

Narrow the review with an explicit `--path <scope>` so only relevant files are diffed
Increase `--max-chars` only if the selected model's context window can accept the complete input
Reduce the diff itself: split the change, or exclude generated/vendored files from the review scope

Example fix

// before
codewhale review            # 900k-char diff vs 200k limit
// after
codewhale review --path crates/tui --max-chars 200000

Defensive patterns

Strategy: validation

Validate before calling

let chars: usize = git_diff.chars().count();
if chars > max_chars { /* narrow with --path or raise max_chars before invoking review */ }

Prevention

Always scope reviews with --path on large working trees
Check diff size (`git diff | wc -m`) before running the review
Raise --max-chars only after confirming the model's context window

When it happens

Trigger: `ensure_local_review_diff_fits` finds `diff.chars().count() > max_chars` — the full working-tree diff (no --path scope) is larger than the review character budget.

Common situations: Reviewing a big refactor or vendored-code drop with the default limit; diffing binary-ish or generated files that inflate the diff; running against a monorepo without narrowing scope.

Understand the failure class

Background: payload too large / request exceeds maximum size: why libraries cap bytes and how to fix oversize payloads — this error's family across 50 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/f105cd1262c382ac. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/lib.rs:9871

        let output = cmd
            .output()
            .map_err(|e| anyhow::anyhow!("Failed to run git diff. Is git installed? ({e})"))?;
        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            bail!("git diff failed: {}", stderr.trim());
        }
        String::from_utf8_lossy(&output.stdout).to_string()
    };
    if args.pr.is_none() {
        ensure_local_review_diff_fits(&diff, args.max_chars)?;
    }
    Ok(diff)
}

fn ensure_local_review_diff_fits(diff: &str, max_chars: usize) -> Result<()> {
    let chars = diff.chars().count();
    if chars > max_chars {
        bail!(
            "Complete local diff requires {chars} characters, exceeding the review limit of {max_chars}. No review was run and no receipt was written or accepted. Select an explicit --path scope, or increase --max-chars only if the selected model can accept the complete input."
        );
    }
    Ok(())
}

fn review_target_label(args: &ReviewArgs) -> String {
    let mut label = if let Some(number) = args.pr {
        format!("pr:{number}")
    } else if args.staged {
        "staged".to_string()
    } else if let Some(base) = args
        .base
        .as_deref()
        .map(str::trim)
        .filter(|base| !base.is_empty())
    {
        format!("base:{base}")

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