cross-rs/cross · error · eyre::ErrReport

unexpected progress type: expected plain, auto, or tty and…

Error message

unexpected progress type: expected plain, auto, or tty and got {s}

What it means

`Progress::from_str` parses a Docker progress output type and only accepts the exact strings "plain", "auto", or "tty". Any other value (including empty or mixed case) fails with this message naming the offending input.

Solutions

Use exactly one of: plain, auto, tty (lowercase).
Remove the progress override to fall back to the default (auto).
If the value comes from a script/CI variable, echo it and fix the casing/spelling.

Example fix

// before
let p = Progress::from_str("TTY")?; // fails
// after
let p = Progress::from_str("tty")?;

Defensive patterns

Strategy: validation

Validate before calling

const VALID: [&str; 3] = ["plain", "auto", "tty"];
if !VALID.contains(&progress) { return Err(format!("progress must be one of {VALID:?}, got {progress}")); }

Type guard

fn is_progress(s: &str) -> bool { matches!(s, "plain" | "auto" | "tty") }

Prevention

Whitelist-check CLI/env inputs against plain|auto|tty before constructing Progress.
Never mix case; lowercase user input and reject anything not exactly matching.
Default to Progress::Auto when the value is empty or absent.

When it happens

Trigger: Passing an unrecognized value for the progress option, e.g. a `--progress` CLI flag set to "tty1", "Plain", "", or "verbose".

Common situations: Typo in the progress flag, copying a value from a different Docker client version that supports other modes, environment variables with stale progress settings, or case-sensitivity mistakes.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of cross-rs/cross@8c1a8aa4b6 (2026-09-13). Data as JSON: /api/errors/5d714d1e427bc298. Report an issue: GitHub.

Appendix: source

Thrown at src/docker/build.rs:24

use crate::errors::*;
use crate::shell::Verbosity;

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum Progress {
    Plain,
    Auto,
    Tty,
}

impl FromStr for Progress {
    type Err = eyre::ErrReport;

    fn from_str(progress: &str) -> Result<Self> {
        Ok(match progress {
            "plain" => Progress::Plain,
            "auto" => Progress::Auto,
            "tty" => Progress::Tty,
            s => eyre::bail!("unexpected progress type: expected plain, auto, or tty and got {s}"),
        })
    }
}

impl From<Progress> for &str {
    fn from(progress: Progress) -> Self {
        match progress {
            Progress::Plain => "plain",
            Progress::Auto => "auto",
            Progress::Tty => "tty",
        }
    }
}

pub trait BuildCommandExt {
    fn invoke_build_command(&mut self) -> &mut Self;
    fn progress(&mut self, progress: Option<Progress>) -> Result<&mut Self>;
    fn verbose(&mut self, verbosity: Verbosity) -> &mut Self;

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