jdx/mise · error

oci mount_point must not be empty

Error message

oci mount_point must not be empty

What it means

The OCI builder resolves the container's mount point from the build request, then the project [oci] settings, then Settings::get().oci.default_mount_point. After trimming trailing slashes it refuses to continue if the resulting path is empty, because an empty mount point would map MISE_DATA_DIR to the container root and corrupt/confuse tool layout. This is a fail-fast validation before any image layers are built.

Solutions

  1. Set a valid absolute mount point in settings: `mise settings set oci.default_mount_point /mise` (or set [oci] mount_point in the project config).
  2. If the build request sets mount_point, change it to a non-empty absolute path like "/opt/mise-data".
  3. Check for config templating that resolves to an empty value (e.g. an unset env var interpolated into the setting).

Example fix

// before (settings.toml)
[oci]
default_mount_point = ""

// after
[oci]
default_mount_point = "/mise"
Defensive patterns

Strategy: validation

Validate before calling

let mp = std::env::var("MISE_OCI_DEFAULT_MOUNT_POINT").unwrap_or_default();
if mp.trim_end_matches('/').is_empty() {
    return Err("oci mount_point must be set to a non-empty absolute path".into());
}

Prevention

When it happens

Trigger: Calling build (via send) when every source is empty: the request's mount_point is Some("") or None, self.oci.mount_point is empty/None, and oci.default_mount_point in settings is an empty string (or only slashes, which trim to "").

Common situations: Users set `[oci] default_mount_point = ""` or `mount_point = "/"` in settings; a config template expands a variable to an empty string; a new install where the default was never populated.

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

AI-assisted analysis of jdx/mise@533346cc37 (2026-09-17). Data as JSON: /api/errors/40670066f6bf01d3. Report an issue: GitHub.

Appendix: source

Thrown at src/oci/builder.rs:190

    pub(crate) async fn build(self) -> Result<BuildOutput> {
        let versions = self.ts.list_current_versions();
        if versions.is_empty() {
            warn!("mise oci build: no tools in the toolset — image will have only the base layer");
        }
        reject_unsupported_backends(&versions)?;

        file::create_dir_all(&self.opts.out_dir)?;
        let layout = ImageLayout::init(&self.opts.out_dir)?;

        let mount_point = self
            .opts
            .mount_point
            .clone()
            .or_else(|| self.oci.mount_point.clone())
            .unwrap_or_else(|| Settings::get().oci.default_mount_point.clone());
        let mount_point = mount_point.trim_end_matches('/').to_string();
        if mount_point.is_empty() {
            bail!("oci mount_point must not be empty");
        }
        if !mount_point.starts_with('/') {
            bail!(
                "oci mount_point must be an absolute path (got {mount_point:?}); \
                 a relative value makes MISE_DATA_DIR inside the container \
                 depend on the working directory and mis-resolve tools."
            );
        }

        let owner = resolve_layer_owner(self.opts.owner, &self.oci);
        let copies: Vec<&OciCopy> = self.oci.copy.iter().chain(&self.opts.copy).collect();

        // --- 1. Base image (optional) ---
        let from_ref = self
            .opts
            .from
            .clone()
            .or_else(|| self.oci.from.clone())

View on GitHub (pinned to 533346cc37)