rtk-ai/rtk · error · anyhow::Error

negative string length: {}

Error message

negative string length: {}

What it means

read_dotnet_string decodes a 7-bit length then reads that many bytes as UTF-8. A negative length is impossible for a valid string, so it means the stream is corrupt or the reader is desynchronized. The subsequent read_exact would also fail on absurd lengths.

Source

Thrown at src/cmds/dotnet/binlog.rs:631

        let mut shift = 0;
        loop {
            let byte = self.read_u8()?;
            value |= ((byte & 0x7F) as u32) << shift;
            if (byte & 0x80) == 0 {
                return Ok(value as i32);
            }

            shift += 7;
            if shift >= 35 {
                anyhow::bail!("invalid 7-bit encoded integer");
            }
        }
    }

    fn read_dotnet_string(&mut self) -> Result<String> {
        let len = self.read_7bit_i32()?;
        if len < 0 {
            anyhow::bail!("negative string length: {}", len);
        }
        let bytes = self.read_exact(len as usize)?;
        String::from_utf8(bytes.to_vec()).context("invalid UTF-8 string")
    }
}

pub fn scrub_sensitive_env_vars(input: &str) -> String {
    SENSITIVE_ENV_RE
        .replace_all(input, "${prefix}[REDACTED]")
        .into_owned()
}

pub fn parse_build_from_text(text: &str) -> BuildSummary {
    let text = text.replace("\r\n", "\n");
    let clean = strip_ansi(&text);
    let scrubbed = scrub_sensitive_env_vars(&clean);
    let mut seen_errors: HashSet<(String, String, u32, u32, String)> = HashSet::new();
    let mut seen_warnings: HashSet<(String, String, u32, u32, String)> = HashSet::new();

View on GitHub (pinned to 36788f6bd4)

Solutions

1. Regenerate the binlog — treat this file as corrupt
2. Check integrity (checksum) if the file came from CI or a share
3. Confirm it is a binlog (magic header), not a misnamed file

match parse_events_from_binlog(&path) {
    Ok(b) => use_events(&b),
    Err(e) if e.to_string().contains("negative string length") => {
        eprintln!("binlog corrupt; regenerate from a clean build");
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: An event field containing a string whose encoded length decodes negative, occurring during read_event_fields driven by parse_events_from_binlog — corrupt payload or mid-stream misalignment.

Common situations: Truncated/partially written binlogs; non-binlog files fed to the parser; corrupted artifacts transferred between machines.

Related errors

• negative record length: {}
• negative event length: {}
• invalid 7-bit encoded integer
• unexpected end of stream
• Failed to parse binlog at {}: empty file

AI-assisted analysis of rtk-ai/rtk@36788f6bd4 (2026-09-03). Data as JSON: /api/errors/f8a75596dce35f30. Report an issue: GitHub.