We need to .collect_vec() the parents iterator to temporary buffer since the
borrowed iterator can't be returned back to the dag_walk functions. Another
option is to clone op_store and parent ids to remove &self lifetime from the
iterator, but that also means a temporary Vec is created.
Suppose the operation log is mostly linear, this means "jj op log" iterator
won't look ahead more than one entry.
Another idea is to either add a "generation" number to operation data, or
build index of operations. Since we'll eventually add GC command, I don't
think op index would be required. I think readdir() is good enough to resolve
hex prefix against ~10k entries.
For now, walk_ancestors() is a free function. If we add Repo-like abstraction
over OpStore + OpHeadsStore, this function will probably be migrated there.
Let's acknowledge everyone's contributions by replacing "Google LLC"
in the copyright header by "The Jujutsu Authors". If I understand
correctly, it won't have any legal effect, but maybe it still helps
reduce concerns from contributors (though I haven't heard any
concerns).
Google employees can read about Google's policy at
go/releasing/contributions#copyright.
