Mercurial's "phase" concept is important for evolution, and it's also
useful for filtering out uninteresting commits from log
output. Commits are typically marked "public" when they are pushed to
a remote. The CLI prevents public commits from being rewritten. Public
commits cannot be obsolete (even if they have a successor, they won't
be considered obsolete like non-public commits would).
This commits just makes space for tracking the public heads in the
View.
All commits in the view are supposed to be reachable from its
heads. If a head is removed and there are git refs pointing to
ancestors of it (or to the removed head itself), we should make that
ancestor a head.
The only invariant we currently enforce is that the set of heads does
not include any ancestors of other commits in the set. I'm about to
make sure that we don't end up with dangling git refs (pointing to
commits no reachable from the heads). It will be useful to have a
single place to enforce that since we'll need to do the same thing
after updating the view as after merging views.
I think it's better to let the caller decide if the parents should be
added. One use case for removing a head is when fetching from a Git
remote where a branch has been rewritten. In that case, it's probably
the best user experience to remove the old head. With the current
semantics of `View::remove_head()`, we would need to walk up the graph
to find a commit that's an ancestor and for each commit we remove as
head, its parents get temporarily added as heads. It's much easier for
callers that want to add the parents as heads to do that.
Git refs are important at least for understanding where the remote
branches are. This commit adds support for tracking them in the view
and makes `git::import_refs()` update them.
When merging views (either because of concurrent operations or when
undoing an earlier operation), there can be conflicts between git ref
changes. I ignored that for now and let the later operation win. That
will probably be good enough for a while. It's not hard to detect the
conflicts, but I haven't yet decided how to handle them. I'm leaning
towards representing the conflicting refs in the view just like how we
represent conflicting files in the tree.
This is partly to prepare for merging the operations in order of
transaction-commit time (currently merged in order of operation id),
so we can get a predictable order in tests (assuming transactions are
not committed the same millisecond).
The function used to be larger when we had more reference cycles
between e.g. the `WorkingCopy` and `Repo`. Now there's only
`Evolution` left, so let's inline the function.
This commits makes it so that running commands outside a repo results
in an error message instead of a panic.
We still don't look for a `.jj/` directory in ancestors of the current
directory.
I'm preparing to publish an early version before someone takes the
name(s) on crates.io. "jj" has been taken by a seemingly useless
project, but "jujube" and "jujube-lib" are still available, so let's
use those.
I had missed in `git2-rs`'s documentation that you need to check
in a callback if the remote ref(s) got updated by the push or
not. This adds such a check and a new error variant for rejected
branch updates.
I tried to push a commit from my Jujube repo to GitHub using `jj
git push --branch main` and it became clear that we need to pass
SSH credentials. This commit hopefully fixes that. I've only made
it pass credentials for ssh-agent for now, because that seems to
be enough to make it work for me personally. If this commit
becomes visible on GitHub, it should mean that it worked.
When you run e.g. `jj st` outside of a repo, it just
crashes. That'll probably give new users a bad impression, so I
was planning to improve error handling a bit. A good place to
start is by fixing the code I recently added (which obviously
should have been using `thiserror` from the beginning). That's
what this commit does.
Also, this is the first commit in this repo created with
Jujube! I've just started dogfooding it myself.
I've forgotten to close a transaction a few times and while the
message ('assertion failed: self.closed') is clear to me now, it
probably won't be clear to others or to me in the future.
This adds `jj git fetch` for fetching from a git remote. There remote
has to be added in the underlying git repo if it doesn't already
exist. I think command will still be useful on typical small projects
with just a single remote on GitHub. With this and the `jj git push` I
added recently, I think I have enough for my most of my own
interaction with GitHub.
The fact that no commits from the underlying Git repo were imported
when creating a new Jujube repo from it was quite surprising. This
commit finally fixes that.
When using Git as a store, new commits created in the underlying Git
repo are only made visible by making changes on top of them (e.g by
checking them out, so a working copy commit is created on top). That's
especially confusing when creating a new repo backed by an existing
Git repo, because the commits from that repo don't show up.
This commit prepares for fixing that by adding a function for updating
heads based on git refs. Since we don't yet track git refs (or
anything similar), the function just makes sure the refs are visible
in the Jujube repo by making them (anonymous) heads.
`Transaction::add_head()` and others would let the caller add
non-heads to the set (i.e. ancestors of others heads) and the the
non-heads were filterd out when the transaction was committed. That's
a little surprising, so let's try to keep the set valid even within a
transaction. That will surely make commands that add many commits
noticeably slower in large repos. Hopefully we can improve that
later.
Returning the store's internal `git2::Repository` instance wrapped in
a `Mutex` makes it easy to run into deadlocks. Let's return a freshly
loaded repo instance instead.
It's annoying to have to have the Git repo and Jujube repo in separate
directories. This commit adds `jj init --git`, which creates a new
Jujube repo with an empty, bare git repo in `.jj/git/`. Hopefully the
`jj git` subcommands will eventually provide enough functionality for
working with the Git repo that the user won't have to use Git commands
directly. If they still do, they can run them from inside `.jj/git/`,
or create a new worktree based on that bare repo.
The implementation is quite straight-forward. One thing to note is
that I made `.jj/store` support relative paths to the Git repo. That's
mostly so the Jujube repo can be moved around freely.
This commit starts adding support for working with a Jujube repo's
underlyng Git repo (if there is one). It does so by adding a command
for pushing from the Git repo to a remote, so you can work with your
anonymous branches in Jujube and push to a remote Git repo without
having to switch repos and copy commit hashes.
For example, `jj git push origin main` will push to the "main" branch
on the remote called "origin". The remote name (such as "origin") is
resolved in that repo. Unlike most commands, it defaults to pushing
the working copy's parent, since it is probably a mistake to push a
working copy commit to a Git repo.
I plan to add more `jj git` subcommands later. There will probably be
at least a command (or several?) for making the Git repo's refs
available in the Jujube repo.
This adds an interactive mode for `jj restore`. It works by first
creating two temporary directories with the contents of the subset of
files that differ between the two trees, and then letting the user
edit the directory representing the right/after side. This has some
advantages compared to the interactive modes in Git and Mercurial:
* It lets the user edit the final state as opposed to the diff itself
(depending on the diff tool, of course). I think most users find it
easier to edit the file contents than to edit the patch
format.
* It delegates the hard work to a tool that is already written (this
is a big advantage for an immature tool like Jujube, but it is not
an advantage from the user's point of view).
Almost all of the work in this commit went into adding a function that
takes two trees, lets the user edit the diff, and returns a new tree
id. I plan to reuse that function for other interactive commands. One
planned command is `jj edit`, which will let the user edit the changes
in a commit. `jj edit -r abc123` will be mostly about providing a more
intuitive name for `jj restore --source abc123^ --destination abc123`,
plus it will be different for merge commits (it will edit only the
changes in the merge commit). I also plan to add `jj split` by letting
the user edit the full diff, leaving only the parts that should go
into the first commit. Perhaps there will also be commands for moving
part of a commit out of or into a parent commit.
This extracts a bit from `Transaction::check_out()` for taking a
Conflict, materializing it, and writing the resulting plain file to
the store. It will soon be reused.
Before this commit, running Git's GC in a Git repo backing a Jujube
repo would risk deleting the conflict data we store as blobs in the
Git repo. This commit fixes that by adding a Git note pointing to the
conflict blob.
I wasn't able to add a test case for this because libgit2 doesn't
support gc [1]. Just testing that the ref is there doesn't seem very
useful.
[1] https://github.com/libgit2/libgit2/issues/3247
Very little code was saved by reusing `write_file()` and it made it
confusing (needed to provide an unused filename). Also, I'll soon want
access to the `locked_repo` variable in `write_conflict()`.
I have never run into this being a problem in practice, but this
change is a stepping stone for two things:
1. Using exponential backoff for other locks (in particular the
working copy).
2. Making the Git store write a ref for conflict objects, so they
don't get GC'd (I want to do that before even I start dogfooding).
I had tried to generate the protobuf code at build time many months
ago, but decided against it because it slowed down the build too
much. I didn't realize there was the
"cargo:rerun-if-changed=<filename>" feature that time. Given that that
exists, it seems like an obvious win to generate the source code at
build time.
I put the generated sources in `$OUT_DIR` (where [1] says they should
be), then include them in the `protos` module by using the `include!`
macro. The biggest problem with that is that I couldn't get IntelliJ
to understand it, even after enabling the experimental features
described in [2].
[1] https://doc.rust-lang.org/cargo/reference/build-script-examples.html#code-generation
[2] https://github.com/intellij-rust/intellij-rust/issues/1908#issuecomment-592773865
We currently recalculate the entire evolution state whenever a new
commit is added within a transaction. That's clearly wasteful. This
commit makes the state-update incremental.
I'm about to make the evolution state updated incrementally. To be
able to tell if a new commit is divergent, we'll need to keep track of
already existing, non-obsolete commits in the change, even if they're
not divergent before the new commit is added.
A pruned commit just indicates that its predecessors should be evolved
onto the pruned commit's parent instead of onto the pruned commit
itself. The pruned commit itself can be divergent. For example, if
there are several pruned sucessors of a commit, then it's unclear
where the predecessor's children should be rebased to.
I'm about to add more fields to the type and this will help to
slightly reduce the boilerplate for initializing and the maps and sets
and creating the struct.
Before this commit, when the `evolve()` evolved a stack of orphans, it
would use the evolve state from the beginning of the function to
calculate where they should go. That meant that only the bottom-most
orphan(s) would get evolved to their right place. This commit fixes
that by use the Transaction's evolution state.
