Otherwise, "jj init --git-repo ." would create extra table files per commit,
and merge them.
I considered adding an explicit GitBackend method to be called from
git::import_refs(), but the call order matters. The method should be invoked
before calling store.get_commit(..) or mut_repo.add_head(..). Since commits
are likely to be loaded from the head, we can instead make read_commit()
import ancestor metadata at all.
Alternatively, we could make a Git commit hidden until it's inserted into
the extra table. It's rather big change, and I wouldn't like to do that
without thinking more thoroughly.
My first attempt was to fix up corrupted index when merging, but it turned
out to be not easy because the self side may contain corrupted data. It's
also possible that two concurrent commit operations have exactly the same
view state (because change id isn't hashed into commit id), and only the
table heads diverge.
#924
This bug concerns the way `import_refs` that gets called by `fetch` computes
the heads that should be visible after the import.
Previously, the list of such heads was computed *before* local branches were
updated based on changes to the remote branches. So, commits that should have
been abandoned based on this update of the local branches weren't properly
abandoned.
Now, `import_refs` tracks the heads that need to be visible because of some ref
in a mapping keyed by the ref. If the ref moves or is deleted, the
corresponding heads are updated.
Fixes#864
This has several advantages:
* Makes it possible to downcast to non-Git custom backends (might be
useful at Google, but we haven't needed it yet)
* Lets us access more specific functionality on the `GitBackend`,
making it possible to access the `git2::Repository` without
creating a copy of it.
* Removes the dependency on Git from the backend
The current behavior was introduced by 20eb9ecec1 "git: don't abandon
HEAD commit when it loses a branch." While the change made HEAD mutation
behavior more consistent with a plain ref operation, HEAD can also move on
checkout, and checkout shouldn't be considered a history rewriting operation.
I'm not saying the new behavior is always correct, but I think it's safer
than losing old HEAD branch. I also think this change will help if we want
to extract HEAD management function from git::import_refs().
Fixes#1042.
This is another step towards allowing a custom `jj` binary to have its
own index type. We're going to have a server-backed index
implementation at Google, for example.
In `git_fetch()`, any glob present in `globs` is an "allow" mark. Using
`&[]` to represent an "allow-all" may be misleading, as it could
indicate that no branch (only the git HEAD) should be fetched.
By using an `Option<&[&str]>`, it is clearer that `None` means that
all branches are fetched.
Git's HEAD ref is similar to other refs and can logically have
conflicts just like the other refs in `git_refs`. As with the other
refs, it can happen if you run concurrent commands importing two
different updates from Git. So let's treat `git_head` the same as
`git_refs` by making it an `Option<RefTarget>`.
Add a new git.auto-local-branch config option. When set to false, a
remote-tracking branch imported from Git will not automatically create a
local branch target. This is implemented by a new GitSettings struct
that passes Git-related settings from UserSettings.
This behavior is particularly useful in a co-located jj and Git repo,
because a Git remote might have branches that are not of everyday
interest to the user, so it does not make sense to export them as local
branches in Git. E.g. https://github.com/gitster/git, the maintainer's
fork of Git, has 379 branches, most of which are topic branches kept
around for historical reasons, and Git developers wouldn't be expected
to have local branches for each remote-tracking branch.
We already have `create_random_commit()`, which returns a
`CommitBuilder`. Most callers directly write that to a
`MutableRepo`. That currently returns a `Commit`, but I'm about to
make it propagate errors from the backend. That would add an
`unwrap()` to this sequence, making it longer. Let's create a simple
helper for these callers to simplify this common pattern.
When you're done with the `CommitBuilder`, you're going to have to
call `write_to_repo()`, passing it a mutable `MutableRepo`
reference. It's a bit simpler to pass that reference when we create
the `CommitBuilder` instead, so that's what this patch does.
A drawback of passing in the mutable reference when we create the
builder is that we can't have multiple unfinished `CommitBuilder`
instance live at the same time. We don't have any such use cases yet,
and it's not hard to work around them, so I think this change is worth
it.
@yuja asked on #701 about the difference between the state in the
`git_export_view` and what we have in `mut_repo.view()`. It's true
that the branches in `mut_repo.view().git_refs()` should match what we
wrote to disk. We can therefore remove the on-disk storage and
simplify quite a bit. For now, I create the `last_export_view` from
the `mut_repo.view().git_refs()` before calling
`export_changes()`. I'll clean up a bit more next.
I think this is correct even considering e.g. undo. Let's consider
what would happen in a non-colocated Git repo (not because tricky
cases cannot happen there but because the explicit exports and imports
make it easier to discuss, and more cases can occur). If the user
moved a branch and then did `jj git export`, `jj undo`, and then `jj
git export` again, we would think on the second export that we should
perform the same changes to the Git repo, which should have no effect.
This patch also fixes the bug we were forced to work around in the
test case in the previous patch.
This removes one of our uses of Thrift.
This fixes the bugs shown by the tests added in the previous patch by
checking that the git branches we're about to update have not been
updated by git since our last export. If they have, we fail those
branches. The user can then re-import from the git repo and resolve
any conflicts before exporting again.
I had to update the `test_export_import_sequence` to make it
pass. That shows a new bug, which I'll fix next. The problem is that
the exported view doesn't get updated on import, so we would try to
export changes compared to an earlier export, even though we actually
knew (because of the `jj git import`) that the state in git had
changed.
If you update a branch using regular `git` (or some Git-based tool)
between two `jj git export`, we will overwrite that change if you had
also changed the branch in jj land. There's a similar problem if you
delete the branch in jj land. Let's have a test for that. I'm going to
make us not overwrite it soon. This patch adds a test for those cases,
plus many other cases in consistent way. Since the new test covers
some cases tested by existing tests, I removed those tests.
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.
To reduce conflicts between branches like `main` and `main/sub`, it's
better to first delete refs in git that have been deleted in jj, and
then add/update refs that have been added/updated in jj.
Since we now write a (partial) view object of the exported branches to
disk (since 7904474320), we can safely skip exporting some
branches. We already skip conflicted branches. This commit makes us
also skip branches that we fail to write to the backing Git repo,
instead of failing the whole operation (after possibly updating some
Git refs).
I made the `export_refs()` function return the branches that
failed. We should probably make that a struct later and have a
separate field for branches that we skipped due to conflicts.
Closes#493.
This adds a test for attempting to export both a branch called `main`
and one called `main/sub` (#493), as well as for exporting a branch
with an empty string as name (reported directly to me by @lkorinth).
We currently get the hostname and username from the `whoami` crate. We
do that in lib crate, without giving the caller a way to override
them. That seems wrong since it might be used in a server and
performing operations on behalf of some other user. This commit makes
the hostname and username configurable, so the calling crate can pass
them in. If they have not been passed in, we still default to the
values from the `whoami` crate.
When we export branches to Git, we didn't update our own record of
Git's refs. This frequently led to spurious conflicts in these refs
(e.g. #463). This is typically what happened:
1. Import a branch pointing to commit A from Git
2. Modify the branch in jj to point to commit B
3. Export the branch to Git
4. Update the branch in Git to point to commit C
5. Import refs from Git
In step 3, we forgot to update our record of the branch in the repo
view's `git_refs` field. That led to the import in step 5 to think
that the branch moved from A to C in Git, which conflicts with the
internal branch target of B.
This commit fixes the bug by updating the refs in the `MutableRepo`.
Closes#463.
As I said in the previous patch, I don't know why I made the initial
export to Git a no-op. Exporting everything makes more sense to
(current-)me. It will make it slightly easier to skip exporting
conflicted branches (#463). It also lets us remove a `jj export` call
from `test_templater.rs`.
To fix#463, I think we want to skip conflicted branches when we
export instead of erroring out. It seems we didn't have test case for
the current behavior, so let's add one.
This is a test case for #463. It's not exactly the same case, but I'm
confident that the root cause is the same (that the
`.jj/repo/git_export_operation_id` doesn't include the git refs we
just updated).
These calls often appear in expressions long enough that not having to
qualify it means that we can sometimes avoid wrapping a line. I
noticed because IntelliJ told me that `test_git.rs` had some
unnecessary qualificiations (the function was already imported there).
The `testutils` module should ideally not be part of the library
dependencies. Since they're used by the integration tests (and the CLI
tests), we need to move them to a separate crate to achieve that.
If you remove all refs from the backing Git repo and then run `jj git
import`, we would see that all commits disappeared from the Git repo,
so we would remove them from the jj repo too. However, we do that by
doing a history walk from old heads to the new heads, which includes
the root commit when the new heads is an empty set. That means that we
mark the root commit as abandoned, which led to a crash in
`rewrite.rs` (when we try pick the root commit's first parent to use
as parent for rebased commits).
I was trying to create a reproduction script for #412, but the script
ran into another bug first. The script removed all the local and
remote branches from the backing Git repo. I noticed that we would
then try to abandon all commits. We should still count Git HEAD's
target as visible and not try to abandon it. This patch fixes that.
The `ReadonlyRepo::init_*()` functions were unused or used only in
tests. Let's remove them, thereby making the repo less aware of
specific backend implementations.
