What causes "brew-cask: structured copy source '{}' was not found" in jdx/mise?

Check the resolved path exists in the staging directory; fix the source template/path in the cask definition.

brew-cask: structured copy source '{}' was not found

Error message

brew-cask: structured copy source '{}' was not found

What it means

The resolved source path of a brew-cask structured copy step does not exist on disk. The library checks existence after resolving the cask's source path (template-expanded against staged_path/appdir) and refuses to copy a missing artifact.

Source

Thrown at src/system/packages/brew/cask/flight.rs:654

            }
        }
        FlightStep::Copy {
            source,
            target,
            recursive,
            overwrite,
            source_glob,
            guards,
        } => {
            if !flight_guards_pass(cask, guards, staged_path, appdir)? {
                return Ok(());
            }
            let sources = flight_symlink_sources(cask, source, *source_glob, staged_path, appdir)?;
            let [source] = sources.as_slice() else {
                bail!("brew-cask: structured copy source must resolve to exactly one path");
            };
            if !source.exists() {
                bail!(
                    "brew-cask: structured copy source '{}' was not found",
                    source.display()
                );
            }
            if source.is_dir() && !recursive {
                bail!("brew-cask: structured directory copy requires recursive=true");
            }
            let target = resolve_flight_path_with_context(cask, target, staged_path, appdir)?;
            let external = !target.starts_with(staged_path);
            let target_metadata = target.symlink_metadata().ok();
            if target_metadata.is_some() {
                if !overwrite {
                    bail!(
                        "brew-cask: structured copy target '{}' already exists",
                        target.display()
                    );
                }
                if external {

View on GitHub (pinned to afd2eddd3a)

Solutions

Check the resolved path exists in the staging directory; fix the source template/path in the cask definition.
Ensure no earlier flight step (Remove/Move) deletes the file before the Copy step runs.
Verify against the currently installed version's staged contents — upstream may have renamed the artifact.

Example fix

// before
source: "bin/legacy-cli"
// after (renamed in new version)
source: "bin/new-cli"

Defensive patterns

Strategy: validation

Validate before calling

let source = resolve_flight_path_with_context(cask, source, staged_path, appdir)?;
if !source.exists() {
    return Err(eyre!("copy source missing: {}", source.display()));
}

Prevention

Verify template variables ({{version}}, {{arch}}) render to real paths in the staged tree.
Order flight steps so sources are not removed before copying.
Re-check the cask definition after upstream app bundle renames.

When it happens

Trigger: FlightStep::Copy whose source path (literal or glob result) is absent at execution time: wrong template variable ({{version}}, {{arch}}), file removed by an earlier Remove/Move step, or upstream changed bundled filenames.

Common situations: Cask definitions pinning old artifact names after an app restructured its bundle; macOS app bundles renamed between versions; source referencing a path created only under a guard that didn't pass.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

AI-assisted analysis of jdx/mise@afd2eddd3a (2026-09-09). Data as JSON: /api/errors/2743fd6051e5d7d9. Report an issue: GitHub.