proposal: os: extend Root FS with interface io/fs.SubFS

[dolmen]

Proposal Details

Extend type os.Root by implementing interface io/fs.SubFS.

The implementation is almost trivial as os.Root already has an OpenRoot method:

func (rfs *rootFS) Sub(dir string) (fs.FS, error) {
    if !isValidRootFSPath(dir) {
        return nil, &PathError{Op: "sub", Path: dir, Err: ErrInvalid}
    }
    r, err := (*Root)(rfs).OpenRoot(dir)
    if err != nil {
        return nil, err
    }
    return r.FS(), nil
}

var _ fs.SubFS = (*rootFS)(nil)

The documentation of os.Root.FS() will be extend to link to fs.SubFS.

[gabyhelp]

Related Issues

• proposal: os: add FS() (filesystem simply using os functions) #47803 (closed)

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[ianlancetaylor]

CC @neild

[neild]

This seems like an obvious and useful addition to os.Root. I support this proposal.