use std::io; use git_repository as git;#[cfg(feature = "serde1")]use git_repository::mailmap::Entry; use crate::OutputFormat; #[cfg(feature = "serde1")]#[cfg_attr(feature = "serde1", derive(serde::Serialize))]struct JsonEntry {    new_name: Option<String>,    new_email: Option<String>,    old_name: Option<String>,    old_email: String,} #[cfg(feature = "serde1")]impl<'a> From<Entry<'a>> for JsonEntry {    fn from(v: Entry<'a>) -> Self {        use git_repository::bstr::ByteSlice;        JsonEntry {            new_name: v.new_name().map(|s| s.to_str_lossy().into_owned()),            new_email: v.new_email().map(|s| s.to_str_lossy().into_owned()),            old_name: v.old_name().map(|s| s.to_str_lossy().into_owned()),            old_email: v.old_email().to_str_lossy().into_owned(),        }    }} pub fn entries(    repo: git::Repository,    format: OutputFormat,    #[cfg_attr(not(feature = "serde1"), allow(unused_variables))] out: impl io::Write,    mut err: impl io::Write,) -> anyhow::Result<()> {    if format == OutputFormat::Human {        writeln!(err, "Defaulting to JSON as human format isn't implemented").ok();    }     let mut mailmap = git::mailmap::Snapshot::default();    if let Err(e) = repo.open_mailmap_into(&mut mailmap) {        writeln!(err, "Error while loading mailmap, the first error is: {}", e).ok();    }     #[cfg(feature = "serde1")]    serde_json::to_writer_pretty(        out,        &mailmap.entries().into_iter().map(JsonEntry::from).collect::<Vec<_>>(),    )?;     Ok(())}