We no longer need the commit ID, so we shouldn't make the callers pass
it. This lets us simplify several tests, because they no longer to
create commits just to check out a tree in the working copy.
We used to use the value to detect races, but we use the tree ID and
the operation ID these days, so we don't need the commit ID.
By changing this, we can avoid creating some commit IDs in tests,
which is why I tackled this issue now.
There are only two callers of `LockedWorkingCopy::check_out()`. One is
in `commands.rs`. That caller already checks after taking the lock
that the old commit ID is as expected. The other caller is
`WorkingCopy::check_out()`. We can simply move the check to that level
since it's the only caller that cares now.
`LockedWorkingCopy::discard()` shouldn't result in changes to the
on-disk state, but `LockedWorkingCopy::check_out()` may have already
written a state file, which is surprising. The changes also remain in
memory, which is also surprising. Let's fix both of those issues.
When there are concurrent operations that want to update the working
copy, it's useful to know which operation was the last to successfully
update the working copy. That can help use decide how to resolve a
mismatch between the repo view's record and the working copy's
record. If we detect such a difference, we can look at the working
copy's operation ID to see if it was updated by an operation before or
after we loaded the repo.
If the working copy's record says that it was updated at operation A
and we have loaded the repo at operation B (after A), we know that the
working copy is stale, so we can automatically update it (or tell the
user to run some command to update it if we think that's more
user-friendly).
Conversely, if we have loaded the repo at operation A and the working
copy's record says that it was updated at operation B, we know that
there was some concurrent operation that updated it. We can then
decide to print a warning telling the user that we skipped updating
because of the conflict. We already have logic for not updating the
working copy if the repo is loaded at an earlier operation, but maybe
we can drop that if we record the operation in the working copy (as
this patch does).
Having the checkout functionality in `LockedWorkingCopy` makes it a
little more flexible (one could imagine using it for udating working
copy files and then discarding the state changes, for example). It
also lets us reuse a few lines of code for locking. I left
`WorkingCopy::check_out()` for convenience because that's what all
current users want.
`WorkingCopy::check_out()` currently fails if the commit recorded on
disk has changed since it was last read. It fails with a "concurrent
checkout" error. That usually works well in practice, but one can
imagine cases where it's not correct. For an example where the current
behavior is wrong, consider this sequence of events:
1. Process A loads the repo and working copy.
2. Process B loads the repo at operation A. It has not loaded the
working copy yet.
3. Process A writes an operation and updates the working copy.
4. Process B loads the working copy and sees that it is checked out
to the commit process B set it to. We don't currently have any
checks that the working copy commit matches the view's checkout
(though I plan to add that).
5. Process B finishes its operation (which is now divergent with the
operation written by process A). It updates the working copy to
the checkout set in the repo view by process B. There's no data
loss here, but the behavior is surprising because we would usually
tell the user that we detected a concurrent update to the working
copy.
We should instead check that the working copy's commit on disk matches
what the previous repo view said, i.e. the view at the start of the
operation we just committed. This patch does that by having the caller
pass in the expected old commit ID.
We already have two usecases that can be modeled as updating the
`TreeState` without touching the working copy:
1. `jj untrack` can be implemented as removing paths from the tree
object and then doing a reset of the working copy state.
2. Importing Git HEAD when sharing the working copy with a Git repo.
This patch adds that functionality to `TreeState`.
I was surprised that we save the `TreeState` before
`LockedWorkingCopy::finish()`. That means that even if the caller
instead decides to discard the changes, some changes will already have
been written.
This patch changes the interface for making changes to the working
copy by replacing `write_tree()` and `untrack()` by a single
`start_mutation()` method. The two functions now live on the returned
`LockedWorkingCopy` object instead. That is more flexible because the
caller can make multiple changes while the working copy is locked. It
also helps us reduce the risk of buggy callers that read the commit ID
before taking the lock, because we can now make it accessible only on
`LockedWorkingCopy`.
The working copy object knows the currently checked out commit ID. It
is set to `None` when the object is initialized. It is also set to
`None` when an existing working copy is loaded. In that case, it's
used only to facilitate lazy loading. However, that means that
`WorkingCopy::current_commit_id()` fails if the working copy has been
initalized but no checkout has been specified. I've never run into
that case, but it's ugly that it can happen. This patch fixes it by
having `WorkingCopy::init()` take a `CommitId`.
`WorkingCopy::current_commit()` has been there from the beginning. It
has made less sense since we made the repo view keep track of the
current checkout. Let's remove it.
I think these remaining implementations of `Drop` are for types that
are infrequently dropped (unlike `Transaction`), so it be fine to be
more strict about them.
The recent e5dd93cbf7, whose description says "cleanup: make Vec
inside CommitId etc. non-public", made all ID types in the `backend`
module *except* for `CommitId` non-public :P This patch makes
I realized only recently that we can try to parse conflict markers in
files and leave them as conflicted if they haven't changed. If they
have changed and some conflict markers have been removed, we can even
update the conflict with that partial resolution.
This change teaches the working copy to write conflicts to the working
copy. It used to expect that the caller had already updated the tree
by materializing conflicts. With this change, we also start parsing
the conflict markers and leave the conflicts unresolved in the working
copy if the conflict markers remain.
There are some cases that we don't handle yet. For example, we don't
even try to set the executable bit correctly when we write
conflicts. OTOH, we didn't do that even before this change.
We still never actually write conflicts to the working copy (outside
of tests) because we currently materialize conflicts in
`MutRepo::check_out()`. I'll change that next.
On Windows, we preserve the executable bit. I plan to also teach the
working copy to preserve conflict state. This refactoring prepares for
that by simplifying how we preserve parts of the current file state.
We have had support for ignores via `.gitignore` files since
3b326a942c, and we haven't had the problem with the temporary
`.git/` directory created by libgit2 since 88f7f4732b.
Git doesn't want `.git` entries in its trees, so at least when using
the Git backend, we need to ignore such paths. Let's just ignore
`.git` paths regardless of backend to keep it simple.
Closes#24.
The auto-rebasing of descendants doesn't work if you have an open
commit checked out, which means that you may still end up with orphans
in that case (though that's usually a short-lived problem since they
get rebased when you close the commit). I'm also about to make
branches update to successors, but that also doesn't work when the
branch is on a working copy commit that gets rewritten. To fix this
problem, I've decided to let the caller of `WorkingCopy::commit()`
responsible for the transaction.
I expect that some of the code that this change moves from the lib
crate to the cli crate will later move back into the lib crate in some
form.
Unlike the other places I fixed in 134940d2bb, the calls in
`working_copy.rs` should not simply use an existing file if the target
file was open. They should probably try again instead, but I'll leave
that for later.
On Windows, it seems that you can't rename a file if the target file
is open (Stebalien/tempfile#131). I think that's the reason for our
failing tests on Windows. This patch adds a simple wrapper around
`NamedTempFile::persist()` that returns the existing file instead of
failing, if there is one.
This change teaches `Tree::diff()` to filter by a matcher. It only
filters the result so far; it does not restrict the tree walk to what
`Matcher::visit()` says is necessary yet. It also doesn't teach the
CLI to create a matcher and pass it in.
