Function convert 

pub fn convert(
    key: Option<&MasterKey>,
    name: &[u8],
    content: &[u8],
) -> Result<Outcome>

Turns one file’s bytes into the text git should diff.

Split from run so the decision is testable without a repository on disk, and so the decryption itself goes through decide::smudge — the very function the checkout path calls. A second implementation here is exactly what the roadmap names as this slice’s risk: it would drift from the format the first time the format changes.

Errors

As run, minus the I/O.