Now that we remove hidden heads whenever a transaction commits,
`non_obsolete_heads()` should always be the same as `all_heads()`,
except during a transaction. I don't think we depend on the difference
even during a transaction. Let's simplify a bit by removing the revset
function `all_heads()` and renaming `non_obsolete_heads()` to
`heads()`. This is part of issue #32.
Branches and the working copy are currently updated to the parents of
the old commit (if they pointed to the old commit to start
with). That's not what's supposed to happen; they're supposed to be
updated to point to the new commit. This patch fixes that by manually
rebasing the immediate children of the old commit, so that
`MutRepo::create_descendant_rebaser()` will do the right thing.
This patch removes the `jj evolve` command, as part of removing the
evolution feature (#32). The command is very rarely useful since we
started evolving orphans after every transaction. I haven't used `jj
evolve` in many months.
After removing the command, the only good way of resolving divergence
will be `jj abandon` one side of the divergence. We will no longer
have a way of automatically merging the divergent commits. I plan to
add back that functionality, powered by the operation log instead of
the obsolescence log. That will probably take a long time, but it's
not a very high-priority feature anyway, so I think it's okay to lose
it for a while.
This is similar to how a recent change taught `DescendantRebaser` to
update branches pointing to rewritten commits. Now we also update the
checkout if it pointed to a rewritten commit.
This patch moves the logic for updating branches from
`update_branches_after_rewrite()` into `DescendantRebaser`. The
branches are now updated along with each rebased commit rather than
all being updated at the end. The new code uses the information about
rewritten and abandoned commits that `DescendantRebaser` gets from
`MutableRepo`. That is different from the old code, which used the
evolution state. This patch thus moves us one step closer to removing
evolution (#32).
I'm going to teach `DescendantRebaser` to also update local branches
pointing to rewritten commits, taking over the responsibility from
`rewrite::update_branches_after_rewrite()`. For commits that have been
rewritten as multiple new commits (divergent, not split), that
function makes local branches pointing to the old commit point to all
the new commits. To replicate that behavior in `DescendantRebaser`, it
needs to know about divergent changes. This change addresses that.
I recently made the CLI remove hidden heads when a transaction is
committed (38474a9). Let's move that to `Transaction::commit()`, so
the library crate becomes more similar to how the CLI behaves and more
similar to our evolution-less future (#32).
The next patch would otherwise make this test fail because
"transaction 2" tries to point a branch to a commit that's not visible
(because it's created by the concurrent "transaction 1").
This makes `jj rebase` and `jj abandon` rebase descendants using
`MutableRepo::create_descendant_rebaser()`, except that `jj rebase -r`
needs to be special-case since it doesn't rebase descendants onto the
rewritten commit.
This change makes it so we rebase descendants based on the rewrite
information recorded in `MutableRepo` instead of using evolution for
it. This is an important step towards removing evolution (#32).
When we remove evolution (#32), I don't intend to replicate the hack
it had for rebasing descendants onto a split commit. Let's instead
have `jj split` manually rebase descendants of the original commit
onto the second part of the split. We use `DescendantRebaser` for
that. Branches and the working copy pointing to the split commit are
still updated using evolution in
`RepoCommandHelper::finish_transaction()`. I plan to have
`DescendantRebaser` update branches and working copies as well. That
should then also work as expected for `jj split`.
Same reasoning as the previous change.
With this change, I believe we now record all rewritten and abandoned
commits correctly. We're now almost ready to switch the CLI away from
using evolution for automatically rebasing commits.
This change makes `jj squash` and `jj unsquash` record the child or
parent (respectively) as abandoned if it becomes empty. We need to do
that because it won't get automatically recorded by
`CommitBuilder`. We could make `CommitBuilder` record abandoned
commits when `set_pruned()` was called, but that would be
short-sighted since we're about to delete that function as part of
removing support for evolution (#32).
This is part of removing support for evolution (#32). Since
`CommitBuilder` now records rewritten commits in `MutableRepo`, we can
use that recorded information to automatically rebase descendants.
When we remove support for evolution (#32), we need to still make it
easy for application code to rebase descendants of rewritten and
abandoned commits. The way applications currently do that is by using
e.g. `CommitBuilder::for_rewrite_from()` followed by
`evolve_orphans()`. This patch puts some bookkeeping in `MutableRepo`
for rewritten and abandoned commits, along with a function for
creating a `DescendantRebaser` based on it. I'll then make
`CommitBuilder` record rewritten commits there.
After writing a new working copy commit, we update branches pointing
to it, and we rebase descendants on top. However, we should be doing
that in the opposite order, so the branch updates apply to rewritten
descendants as well.
This makes it so that almost every command will remove non-visible
heads. That shouldn't have much visible effect, except that the
`all_heads()` revset will become the same as
`non_obsolete_heads()`.
It will help us remove support for evolution by cleaning up existing
repos. Existing repos (like mine) will lose the unwanted heads (~8.5k
heads in my case), so they don't clutter the repo once evolution is
gone.
This is part of issue #32.
If you rewrite a change twice, from A to A' to A'', then undo the
operation that created A', you'll end up with a repo where A'' refers
to commit (A') that's not reachable from any head in the view. We
currently crash when that happens. This change fixes the
crash. Undoing the A' operation now instead produces a state where A
and A'' are divergent. That at least makes some sense.
This may not seem important since I'm working on removing support for
evolution (#32), but I wanted to get it fixed in order to help with
the transition off of evolution. Specifically, I want to be able to
start removing old heads more freely.
This closes#28.
In the recent switch away from `git2::Remote::fetch()`, I passed
`git2::AutotagOption::All`, which caused cloning of e.g. the `clap`
repo to fail like this:
```
Error: Fetch failed: Error { code: -1, klass: 4, message: "target OID for the reference doesn't exist on the repository" }
```
This commit changes from `All` to `Unspecified`, which respects the
remote's configuration.
The default branch relies on checking the value of `HEAD`. The `empty_git_commit` function updates the ref `refs/heads/main`, but since `HEAD` was never updated to point to that ref, the default branch can't be determined. The fix is to explicitly set `HEAD`.
Personally, this test failed reliably for me on macOS. I don't know why this behavior would be non-deterministic on other platforms.
It seems it wasn't Windows that behaved differently when it comes
getting the remote's default branch; the test failed on Ubuntu
too.
The documentation for `Remote::default_branch()` says that it can be
called even after the connection has been closed, but let's see if
calling it while the connection is open helps anyway. To do that, we
have to replicate what `Remote::fetch()` does.
This change makes it so `jj abandon` uses `DescendantRebaser` for
rebasing descendants of the abandoned commits. That makes it not
depend on evolution for it.
Descendants of abandoned commits should be rebased onto their parents,
or the rewritten parents if they had been rewritten. This patch
teaches `DescendantRebaser` to do that. It updates `jj rebase -r` to
use the functionality. I plan to also use it in `jj abandon`
(naturally, given the name), and for rebasing descendants of deleted
refs imported from `jj git refresh/fetch/push`.
The fact that `DescendantRebaser` visits some commits that don't need
to be rebased is mostly an implementation detail. I can't think of a
reason that callers would care about these commits.
The command's help text says "Abandon a revision", which I think is a
good indication that the command's name should be `abandon`. This
patch renames the command and other user-facing occurrences of the
word. The remaining occurrences should be removed when I remove
support for evolution.
This makes conflicted branches pointing to the working copy get
updated when the working copy changes, just like they are when it
changes for other reason (such as `jj describe`).
This patch moves the function for updating branches after rewrite from
`commands.rs` into `rewrite.rs`.
It also changes the function to update branches even if they were
conflicted or become conflicted. I think that seems better than
leaving branches on old commits. For example, let's say you have start
with this:
```
C main
|
B origin@main
|
A
```
You now pull from origin, which has updated the main branch from B to
B'. We apply that change to both the remote branch and the local
branch, which results in a conflict in the local branch:
```
C main?
|
B B' main? origin@main
|/
A
```
If you now rewrite C to C', the conflicted main branch will still
point to C, which is just weird. This patch changes that so the
conflicted side of main gets repointed to C'.
I also refactored the code to reuse our existing
`MutableRepo::merge_single_ref()`, which improves the behavior in
several cases, such as the conflict-resolution case in the last test
case.
I don't know why I hadn't already updated these. Maybe I thought it
wasn't necessary. That's probably true right now, but I want to make
`jj git fetch` and `jj git refresh` automatically rebase commits when
branches were updated on a remote or in the underlying Git repo. We
want to make sure that the working copy also gets updated then.
As the updates test case shows, when rebasing forward, we missed
commits that fork off from the section between the source and the
destination.
As part of the fix, I also restructured the code a bit to prepare for
support for rebasing descendants of multiple rewritten commits.
I forgot to remove the `fetch_head` from a variable name when I
recently realized that Git's `FETCH_HEAD` is not what we want to check
out after fetching.
