Function require_manifest_support

atomic-cli/src/commands/push/helpers.rs:272–289

Interpret the result of `get_view_manifest`, turning "server predates manifest support" into a hard, actionable error. Identity-preserving push has no fallback: this client no longer flattens views, so a server without `?view-manifest` support cannot be pushed to.

(
    result: Result<Option<String>, RemoteError>,
    url: &str,
)

/// Identity-preserving push has no fallback: this client no longer flattens
/// views, so a server without `?view-manifest` support cannot be pushed to.
pub fn require_manifest_support(
    result: Result<Option<String>, RemoteError>,
    url: &str,
) -> CliResult<Option<String>> {
    match result {
        Ok(text) => Ok(text),
        Err(RemoteError::ProtocolError { message }) => Err(CliError::RemoteError {
            message: format!(
                "The server does not support view manifests ({}). \
                 Identity-preserving push requires a server upgrade; \
                 this client no longer flattens views on push.",
                message
            ),
            url: Some(url.to_string()),
        }),
        Err(e) => Err(convert_remote_error(e, url)),
    }
}

/// Parse and verify a remote manifest, mapping failures to remote errors.
///