pub fn check_update() -> Result<Option<String>>Expand description
Probes for a newer release without installing anything.
Prints an “update available” line and returns Some(tag_name) when a newer
release exists, or None when already current. This is the read-only path
behind vct update --check.
§Errors
Returns an error if the version comparison fails — i.e. the GitHub fetch or
any version parse fails (see get_version_comparison).