Language: Go
Label: safe
CWE: CWE-22 \u2014 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Code:
func (fsys writeMapFS) OpenAppendable(name string) (WritableFile, error) {
	var file = &writableMapFile{
		MapFile: fstest.MapFile{
			Data: []byte("content2"),
		},
	}
	fsys.MapFS[name] = &file.MapFile

	return file, nil
}