Make `git2` an *optional* dependency of `radicle-cob`, and refactor
`radicle` to depend on crates that in turn do not depend on `git2`
*non-optionally*
The main offending dependency of `radicle-cob` is `radicle-git-ext`
from the `radicle-git` workspace in repository
(rad:z6cFWeWpnZNHh9rUW8phgA3b5yGt) which *non-optionally* depends on
`git2`.
So, to achieve removal of this dependency:
1. The crate is refactored to depend on the new crates
`radicle-git-ref-format` `radicle-git-metadata`, and
`radicle-oid` introduced in the previous commits, instead of
`radicle-git-ext`.
2. Some code from the `radicle-git-ext` crate in the `radicle-git`
workspace in repository (rad:z6cFWeWpnZNHh9rUW8phgA3b5yGt) is
copied. See `crates/radicle-cob/src/backend/git/commit.rs`.
This cascades to `radicle` and its dependents.
Firstly, the there is an
`impl Deref<Target=git2::Oid> for radicle_git_ext::Oid`. This made
it very convenient to just deref to obtain the wrapped `git2::Oid`,
so there are many expressions of the shape `*oid` in `radicle` and
its dependents. However `radicle-oid` does not provide
`impl Deref<Target=git2::Oid> for radicle_oid::Oid`, as notably,
`Target` is an associated type, and not a type parameter, so an
implementation of `Deref` would tie the new `Oid` too tightly to a
particular implementation.
Instead, work with `impl From<radicle_oid::Oid> for git2::Oid`
(which can be enabled using the feature flag `radicle-oid/git2`).
This explains the changes from `*oid` to `oid.into()` at every
transition to "`git2` land".
Secondly, `radicle` and its dependents are refactored to also depend
on `radicle-git-ref-format` and (much less prominently)
`radicle-git-metadata` instead of `radicle-git-ext`
This is to avoid pulling in `git2` via these dependencies.
Thirdly, as the re-exports in `crates/radicle/src/git.rs` change,
they are at the same time also cleaned up. Notably, the types from
`radicle-git-ref-format` are re-exported under `fmt` only, not "twice".
While overall this obviously is very much a breaking change, these
changes should mostly amount to changing from `Deref` to `Into`, i.e.,
`*oid` → `oid.into()` and rewriting imports for `radicle::fmt`.
This is indicated by the mostly mechanical nature of the changes to
`crates/radicle-{cli,node,remote-helper}`.
This function (and the helpers `ancestry` and `find_and_peel`) are
eagerly peeling to commits, leading to updates of tags that target the
same commit to be missed.
For example, there could be tag two tag objects with *different* OIDs
A and B, from *different* authors, using *different* tag names, signed
with *different* secret keys, and both pointing to *the same* commit C.
The implementation would consider A and B to be the same, just becuase
A and B both peel to C, skipping the update.
This is counterintuitive, and when combined with canonical references
can be quite confusing.
Change this to only reason about an ancestry if the two objects in
question really both are commits directly. Otherwise, treat cases where
no structure can be used as ancestry similarly to non-fast-forward
updates.