Despite what the documentation said, we don't clear the record of
rewritten and abandoned commits at the end. This change fixes that,
and adds a test showing that it's possible to call
`MutableRepo::rebase_descendants()` multiple times.
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.
If you create a `dir/.gitignore` file with pattern "dir" in it, it'll
currently match the parent directory, making e.g. the `dir/.gitignore`
file itself ignored. That was quite confusing, and it doesn't match
how Git behaves. This patch fixes the bug.
I ran into a tool that produced a `.gitignore` file with CRLF line
endings. I had not considered that case when implementing support for
`.gitignore`, so we interpreted the CR as part of the string, which of
course made the files not match.
This patch fixes the bug by ignoring a single CR at EOL. That seems to
be what Git does (I didn't see any information about it in the
documentation).
A new Clippy version added a new warning when a function that returns
`Self` doesn't have `#[must_use]`. I feel like all the cases reported
by it were false positives. Most were functions on `CommitBuilder`,
where we take `mut self` and return `Self`. I don't think I've ever
forgotten to use the result of those.
It makes sense to omit either of the arguments of the `..` operator,
even though `..x` is equivalent to `:x`. `x..`, with a implied right
argument of `heads()` is more useful.
If you import Git refs, then rebase a commit pointed to by some Git
ref, and then re-import Git refs, you don't want the old commit to be
made a visible head again. That's particularly annoying when Git refs
are automatically updated by every command.
Since 94e03f5ac8, we lazily filter out non-heads from `View`'s set
of head. Accessing the `MutRepo::view()` triggers that filtering. This
patch makes `DescendantRebaser` not unnecessarily do that. That speeds
up the rebasing of 162 descendants in the git.git repo from ~3.6 s to
~330 ms. Rebasing 1272 descendants takes ~885 ms.
When you run e.g. `jj describe <some old commit>` or `jj squash -r
<some old commit>`, the descendants' tree objects will not change, so
we can avoid calculating them. This speeds up rebasing of 126 commits
in the git.git repo from ~9.8 s to ~3.6 s.
I recently (0c441d9558) made it so we don't create an operation when
nothing changed. Soon thereafter (94e03f5ac8), I broke that when I
introduced a cache-invalidation bug when I made the filtering-out of
non-heads be lazy. This patch fixes that and also adds a test to
prevent regressions.
When initializing a jj repo in the same directory as its backing git
repo, add `.jj/` to `.git/info/exclude` so it doesn't show up to `git`
commands.
This is part of #44.
It's very slow to remove non-heads from the set of heads every time we
add an head. For example, in the git.git repo, a no-op `jj git import`
takes ~15 s. This patch changes makes us just mark the set of heads
dirty when a commit has been added and then we remove non-heads when
needed. That cuts down the `jj git import` time to ~200 ms.
It's useful to know which commit is checked out in the underlying Git
repo (if there is one), so let's show that. This patch indicates that
commit with `HEAD@git` in the log output. It's probably not very
useful when the Git repo is "internal" (i.e. stored inside `.jj/`),
because then it's unlikely to change often. I therefore considered not
showing it when the Git repo is internal. However, it turned out that
`HEAD` points to a non-existent branch in the repo I use, so it won't
get imported anyway (by the function added in the previous patch). We
can always review this decision later.
This is part of #44.
This patch adds a place for tracking the current `HEAD` commit in the
underlying Git repo. It updates `git::import_refs()` to record it. We
don't use it anywhere yet.
This is part of #44.
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.
If nothing changed in a transaction, it's rarely useful to commit it,
so let's avoid that. For example, if you run `jj git import` without
changing the anything in the Git repo, we now just print "Nothing
changed.".
