rust-lang/rust-analyzer · error

{:?} failed, {}

Error message

{:?} failed, {}

What it means

utf8_stdout's fallback bail: the command exited non-zero but no usable stderr was captured (empty stderr or invalid UTF-8). It reports only the command and exit status, so the cause must be inferred from the command itself. Same family as the stderr variant but with no diagnostic output attached.

Source

Thrown at crates/project-model/src/lib.rs:220

            | ProjectManifest::CargoScript(it) => it,
        }
    }
}

impl fmt::Display for ProjectManifest {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt::Display::fmt(self.manifest_path(), f)
    }
}

fn utf8_stdout(cmd: &mut Command) -> anyhow::Result<String> {
    let output = cmd.output().with_context(|| format!("{cmd:?} failed"))?;
    if !output.status.success() {
        match String::from_utf8(output.stderr) {
            Ok(stderr) if !stderr.is_empty() => {
                bail!("{:?} failed, {}\nstderr:\n{}", cmd, output.status, stderr)
            }
            _ => bail!("{:?} failed, {}", cmd, output.status),
        }
    }
    let stdout = String::from_utf8(output.stdout)?;
    Ok(stdout.trim().to_owned())
}

#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub enum InvocationStrategy {
    Once,
    #[default]
    PerWorkspace,
}

/// A set of cfg-overrides per crate.
#[derive(Default, Debug, Clone, Eq, PartialEq)]
pub struct CfgOverrides {
    /// A global set of overrides matching all crates.
    pub global: cfg::CfgDiff,

View on GitHub (pinned to e8f7e90aa3)

Solutions

1. Check that `rustc`/`cargo`/`rustup` are installed and on PATH (`which rustc; rustc --version`).
2. Re-run the exact command from the message manually to reproduce and see any output.
3. Fix environment variables (PATH, RUSTUP_HOME, CARGO_HOME, RUSTUP_TOOLCHAIN) that may point at broken installs.
4. If the process is being killed, check memory/disk resources.

Example fix

// before
$ echo $PATH   # rustc not present
// after
$ rustup default stable
$ export PATH="$HOME/.cargo/bin:$PATH"
$ rustc --version

let ok = Command::new("rustc").arg("--version").output()
    .map(|o| o.status.success() && !o.stdout.is_empty())
    .unwrap_or(false);
if !ok { /* repair toolchain / PATH before invoking library code */ }

// no stderr is attached, so retry after fixing the environment
match result {
    Err(e) if e.to_string().contains("failed, exit status") => {
        // re-check PATH/toolchain, then retry once
        retry_after_env_fix()
    }
    other => other,
}

When it happens

Trigger: utf8_stdout running a command that exits non-zero with empty or non-UTF-8 stderr — e.g. `rustc --print sysroot` when rustc is absent from PATH, killed by a signal, or emitting binary garbage on stderr.

Common situations: rustc/cargo not on PATH (broken environment); command killed (OOM/signal) producing no stderr; locale/encoding issues making stderr non-UTF-8; wrapper scripts exiting silently.

Related errors

• {:?} failed, {} stderr: {}

AI-assisted analysis of rust-lang/rust-analyzer@e8f7e90aa3 (2026-09-03). Data as JSON: /api/errors/ffad09ffa17781be. Report an issue: GitHub.