use crate::Error; impl crate::Repository {    /// Create a graph data-structure capable of accelerating graph traversals and storing state of type `T` with each commit    /// it encountered.    ///    /// Note that the `cache` will be used if present, and it's best obtained with    /// [`commit_graph_if_enabled()`](crate::Repository::commit_graph_if_enabled()).    ///    /// Note that a commitgraph is only allowed to be used if `core.commitGraph` is true (the default), and that configuration errors are    /// ignored as well.    ///    /// ### Performance    ///    /// Note that the [Graph][gix_revwalk::Graph] can be sensitive to various object database settings that may affect the performance    /// of the commit walk.    pub fn revision_graph<'cache, T>(        &self,        cache: Option<&'cache gix_commitgraph::Graph>,    ) -> gix_revwalk::Graph<'_, 'cache, T> {        gix_revwalk::Graph::new(&self.objects, cache)    }     /// Return a cache for commits and their graph structure, as managed by `git commit-graph`, for accelerating commit walks on    /// a low level.    ///    /// Note that [`revision_graph()`][crate::Repository::revision_graph()] should be preferred for general purpose walks that don't    /// rely on the actual commit cache to be present, while leveraging the commit-graph if possible.    pub fn commit_graph(&self) -> Result<gix_commitgraph::Graph, Error> {        gix_commitgraph::at(self.objects.store_ref().path().join("info")).map_err(Into::into)    }     /// Return a newly opened commit-graph if it is available *and* enabled in the Git configuration.    pub fn commit_graph_if_enabled(        &self,    ) -> Result<Option<gix_commitgraph::Graph>, super::commit_graph_if_enabled::Error> {        Ok(self            .config            .may_use_commit_graph()?            .then(|| gix_commitgraph::at(self.objects.store_ref().path().join("info")))            .transpose()            .or_else(|err| match err.downcast_any_ref::<std::io::Error>() {                Some(err) if err.kind() == std::io::ErrorKind::NotFound => Ok(None),                _ => Err(err.into_error()),            })?)    }}