---
title: "MGS1013: cross-project output glob escapes its owner"
description: Fires at load when the glob half of a cross-project ctx.writesFiles is absolute or contains .., so it would resolve outside the project that owns it.
tags: [MGS1013, magusfile, outputs, cross-project, globs, containment]
---

# MGS1013: cross-project output glob escapes its owner

The glob in a cross-project `ctx.writesFiles` is absolute or contains `..`, so it
does not name a path inside the project it is declared against.

```text
[MGS1013] workspace://producer: target "build": ctx.writesFiles glob "../../etc/x"
must be relative to "site" and must not contain ..
```

## Why

A cross-project output has two halves, and they are validated for different
reasons:

```buzz
ctx.writesFiles(site.file("generated.txt"));
//          ^^^^      ^^^^^^^^^^^^^^
//          owner     glob, relative to the OWNER's root
```

The owner half says which project's tree the file lands in. The glob half is
relative to **that** project's root, not the declaring one - which is exactly why
magus can file it on the owner and let `clean`, `watch`, ownership lookup and the
merge driver all resolve it against a single root.

That only holds if the glob stays inside the owner. An absolute path or a `..`
escape resolves somewhere else entirely, and every consumer that joins it to the
owner's directory then reads a path the declaration never meant. Outputs in magus
are confined to a project subtree; this is that rule applied to the glob.

The cache enforces the same rule when it snapshots. Checking at load only moves
the failure earlier, and it moves it somewhere much better:

- Before, the glob was accepted, the target **ran**, and the error appeared only
  once work had been done.
- Worse, `magus clean` expands output globs for every project in one loop, so a
  single unexpandable pattern aborted the clean for the **whole workspace** - a
  failure in one project's declaration taking out an unrelated command.

## Resolution

Write the path as the owner sees it. If `site` is at `site/` and the file belongs
at `site/gen/api.ts`, the owner is `site` and the glob is `gen/api.ts`:

```buzz
ctx.writesFiles(site.file("gen/api.ts"));
```

If you find yourself reaching for `..` to get somewhere, the owner is wrong, not
the glob. Import the project that actually contains the destination and declare
against that one. If nothing owns it, it is not a tracked output - see
[MGS1011](MGS1011.md).

## See also

- [MGS1011](MGS1011.md) - a cross-project output naming a project magus cannot use
- [Outputs and the cache](../../../concepts/cache.md)