astrid-runtime/astrid · error

--var has an empty key (got {item:?})

Error message

--var has an empty key (got {item:?})

What it means

`from_cli` parses each `--var KEY=VALUE` item with `split_once('=')`. After splitting, if the key part is empty (e.g. `--var =value` or `--var =`), it bails with this message including the offending item in debug form. It enforces that every variable override has a non-empty key.

Source

Thrown at crates/astrid-cli/src/commands/capsule/install.rs:68

}

/// Operator input policy for a manual capsule install.
#[derive(Debug, Clone, Default)]
pub(super) struct ManualInstallOptions {
    pub(super) yes: bool,
    pub(super) approve_untrusted: bool,
    pub(super) vars: HashMap<String, String>,
}

impl ManualInstallOptions {
    fn from_cli(yes: bool, approve_untrusted: bool, items: &[String]) -> anyhow::Result<Self> {
        let mut vars = HashMap::new();
        for item in items {
            let (key, value) = item
                .split_once('=')
                .ok_or_else(|| anyhow::anyhow!("--var must be KEY=VALUE (got {item:?})"))?;
            if key.is_empty() {
                bail!("--var has an empty key (got {item:?})");
            }
            if vars.insert(key.to_string(), value.to_string()).is_some() {
                bail!("--var '{key}' was supplied more than once");
            }
        }
        Ok(Self {
            yes,
            approve_untrusted,
            vars,
        })
    }
}

#[derive(Clone, Copy)]
pub(crate) struct OfflineCapsuleProvenance<'a> {
    pub(crate) original_source: &'a str,
    pub(crate) resolved_ref: Option<&'a str>,
    pub(crate) signer: Option<&'a str>,

View on GitHub (pinned to affd8760f4)

Solutions

1. Supply the variable as `KEY=VALUE` with a non-empty KEY: `--var MY_VAR=value`.
2. Check shell quoting/expansions — an empty variable before `=` yields an empty key.
3. Review the printed `{item:?}` to see the exact malformed argument the CLI received.
4. Remove the offending `--var` flag if it was added by mistake.

Example fix

// before
--var =value
// after
--var MY_KEY=value

fn validate_var(item: &str) -> Result<(), String> {
    match item.split_once('=') {
        Some((k, _)) if !k.is_empty() => Ok(()),
        _ => Err(format!("--var must be non-empty KEY=VALUE, got {item:?}")),
    }
}
// validate every --var before invoking the CLI

match result {
    Err(e) if e.to_string().contains("empty key") =>
        eprintln!("Fix your --var flags: every entry needs KEY=VALUE with a non-empty KEY."),
    other => other.expect("install failed"),
}

When it happens

Trigger: Running `astrid capsule install` with `--var` whose value has no characters before `=`: `--var =foo`, `--var =`, or a shell-quoting accident that drops the key (e.g. `--var "$EMPTY"=x`).

Common situations: Scripted installs where a variable holding the key is empty; copy-pasted CLI examples with the key lost; shell expansions interpolating to `=value`.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• --var has an invalid key (got {key:?})
• --var has an empty key (got {item:?})
• --var must be KEY=VALUE (got {item:?})
• --retain-entries must be at least 1
• --retain-bytes must be greater than 0

AI-assisted analysis of astrid-runtime/astrid@affd8760f4 (2026-09-09). Data as JSON: /api/errors/c25a437db3a8adc0. Report an issue: GitHub.