Method nearest_shared_ancestor

atomic-repository/src/repository/views.rs:197–234

Walk the parent chain from `view_name` and return the name of the first Shared view encountered. If `view_name` is itself Shared, it is returned immediately. This is used to determine the correct parent for newly created Draft views.

(&self, view_name: &str)

    /// it is returned immediately.  This is used to determine the correct
    /// parent for newly created Draft views.
    pub fn nearest_shared_ancestor(&self, view_name: &str) -> Result<String, RepositoryError> {
        let txn = self
            .pristine
            .read_txn()
            .map_err(|e| RepositoryError::Database(e.to_string()))?;

        let view = txn
            .get_view(view_name)
            .map_err(|e| RepositoryError::Database(e.to_string()))?
            .ok_or_else(|| RepositoryError::ViewNotFound {
                name: view_name.to_string(),
            })?;

        // Already Shared → use it directly.
        if view.kind.is_shared() {
            return Ok(view_name.to_string());
        }

        // Walk up the parent chain looking for a Shared ancestor.
        let mut cursor = view.parent;
        while let Some(parent_id) = cursor {
            if let Some(parent) = txn
                .get_view_by_id(parent_id)
                .map_err(|e| RepositoryError::Database(e.to_string()))?
            {
                if parent.kind.is_shared() {
                    return Ok(parent.name.clone());
                }
                cursor = parent.parent;
            } else {
                break;
            }
        }

        // Fallback: if no Shared ancestor found (shouldn't happen in
        // normal use — dev is always Shared), use the current view.
        Ok(view_name.to_string())
    }

    /// Create a new view that inherits changes from another view.
    ///