Now we have a separate map for "git" tracking remote, we can always preserve
the last imported/exported git_refs. The option to restore git-tracking refs
has been removed. Perhaps, --what can be reorganized as --local and --remote
<NAME>.
The commit backend at Google is cloud-based (and so are the other
backends); it reads and writes commits from/to a server, which stores
them in a database. That makes latency much higher than for disk-based
backends. To reduce the latency, we have a local daemon process that
caches and prefetches objects. There are still many cases where
latency is high, such as when diffing two uncached commits. We can
improve that by changing some of our (jj's) algorithms to read many
objects concurrently from the backend. In the case of tree-diffing, we
can fetch one level (depth) of the tree at a time. There are several
ways of doing that:
* Make the backend methods `async`
* Use many threads for reading from the backend
* Add backend methods for batch reading
I don't think we typically need CPU parallelism, so it's wasteful to
have hundreds of threads running in order to fetch hundreds of objects
in parallel (especially when using a synchronous backend like the Git
backend). Batching would work well for the tree-diffing case, but it's
not as composable as `async`. For example, if we wanted to fetch some
commits at the same time as we were doing a diff, it's hard to see how
to do that with batching. Using async seems like our best bet.
I didn't make the backend interface's write functions async because
writes are already async with the daemon we have at Google. That
daemon will hash the object and immediately return, and then send the
object to the server in the background. I think any cloud-based
solution will need a similar daemon process. However, we may need to
reconsider this if/when jj gets used on a server with a custom backend
that writes directly to a database (i.e. no async daemon in between).
I've tried to measure the performance impact. That's the largest
difference I've been able to measure was on `jj diff
--ignore-working-copy -s --from v5.0 --to v6.0` in the Linux repo,
which increases from 749 ms to 773 ms (3.3%). In most cases I've
tested, there's no measurable difference. I've tried diffing from the
root commit, as well as `jj --ignore-working-copy log --no-graph -r
'::v3.0 & author(torvalds)' -T 'commit_id ++ "\n"'` (to test a
commit-heavy load).
Before this patch, when updating to a commit that has a file that's
currently an ignored file on disk, jj would crash. After this patch,
we instead leave the conflicting files or directories on disk. We
print a helpful message about how to inspect the differences between
the intended working copy and the actual working copy, and how to
discard the unintended changes.
Closes#976.
On my Debian laptop, openssl_init() takes ~30ms to load the default CA
certificates serialized in PEM format, and the cost is added to each jj
invocation. This change saves 20s (of 50s) on my machine.
% wc -l /usr/lib/ssl/cert.pem
3517 /usr/lib/ssl/cert.pem
It's about time we make the working copy a pluggable backend like we
have for the other storage. We will use it at Google for at least two
reasons:
* To support our virtual file system. That will be a completely
separate working copy backend, which will interact with the virtual
file system to update and snapshot the working copy.
* On local disk, we need to tell our build system where to find the
paths that are not in the sparse patterns. We plan to do that by
wrapping the standard local working copy backend (the one moved in
this commit), writing a symlink that points to the mainline commit
where the "background" files can be read from.
Let's start by renaming the exising implementation to
`local_working_copy`.
I've added a boolean flag to the store to ensure that the migration never runs
more than once after the view gets "op restore"-d. I'll probably reorganize the
branches structure to support non-tracking branches later, but updating the
storage format in a single commit would be too involved.
If jj is downgraded, these "git" remote refs would be exported to the Git repo.
Users might have to remove them manually.
I have used the tree-level conflict format for several weeks without
problem (after the fix in 51b5d168ae). Now - right after the 0.10.0
release - seems like a good time to enable the config by default.
I enabled the config in our default configs in the CLI crate to reduce
impact on tests (compared to changing the default in `settings.rs`).
As we can set HEAD to an arbitrary ref by using .reference_symbolic(), we don't
have to manage a ref that can also be valid as a branch name.
Fixes#1495
I'll add a workaround for the root parent issue #1495 there. We can pass in
the wc parent id instead of the wc_commit object, but we might want to use
wc_commit.id() to generate a unique placeholder ref name.
While debugging git issues, I often ended up creating a deadlock by adding
debug prints. It's also not obvious that git::export_refs() works even if the
git_repo() has already been locked, whereas git::import_refs() wouldn't. Let's
consolidate lock handling to the backend implementation.
Apparently, it gets too verbose if the remote history is actively rewritten.
Let's summarize the output for now. The plan is to show the list of moved refs
instead of the full list of abandoned commits.
The codespell GitHub action fails because of the typo. I don't know
why it started failing now. The comment is 8 months old and the
codespell action hasn't been updated in 5 months.
The problem is that the first non-working-copy commit moves the unborn current
branch to that commit, but jj doesn't "export" the moved branch. Therefore,
the next jj invocation notices the "external" ref change, which was actually
made by jj.
I'm not sure why we play nice by setting the "current" HEAD, but I *think* it's
okay to set the "new" HEAD and reset to the same commit to clear Git index.
This will probably help to understand why you've got conflicts after fetching.
Maybe we can also report changed local refs.
I think the stats should be redirected to stderr, but we have many other similar
messages printed to stdout. I'll probably fix them all at once later.
I think most users who change the set of immutable heads away from
`trunk() | tags()` are going to also want to change the default log
revset to include the newly mutable commit and to exclude the newly
immutable commits. So let's update the default log revset to use
`immutable_heads()` instead.
`test_templater` changed because we have overridden the set of
immutable commits there so `jj log` now includes the remote branch.
`jj split` with no arguments operates interactively, but I am nonetheless constantly running `jj split -i` because I expect an `--interactive` flag to exist for consistency.
However, `jj split <paths>` before this commit always operates non-interactively, so this commit has the nice practical effect that you can restrict your interactive splitting to a certain set of paths.
All non-test callers already have a `Merge` object, so let's pass that
instead. We thereby simplify the callers a little, and we enforce the
"adds.len() == removes.len() + 1" constraint in the type.
When there's a single parent, we can determine if a commit is empty by
just comparing the tree ids. Also, when using tree-level conflicts, we
don't need to read the trees to determine if there's a conflict. This
patch adds both of those fast paths, speeding up `jj log -r ::main`
from 317 ms to 227 ms (-28.4%). It has much larger impact with our
cloud-based backend at Google (~5x faster).
I made the same fix in the revset engine and the Git push code (thanks
to Yuya for the suggestion).
This adds a new `revset-aliases.immutable_heads()s` config for
defining the set of immutable commits. The set is defined as the
configured revset, as well as its ancestors, and the root commit
commit (even if the configured set is empty).
This patch also adds enforcement of the config where we already had
checks preventing rewrite of the root commit. The working-copy commit
is implicitly assumed to be writable in most cases. Specifically, we
won't prevent amending the working copy even if the user includes it
in the config but we do prevent `jj edit @` in that case. That seems
good enough to me. Maybe we should emit a warning when the working
copy is in the set of immutable commits.
Maybe we should add support for something more like [Mercurial's
phases](https://wiki.mercurial-scm.org/Phases), which is propagated on
push and pull. There's already some affordance for that in the view
object's `public_heads` field. However, this is simpler, especially
since we can't propagate the phase to Git remotes, and seems like a
good start. Also, it lets you say that commits authored by other users
are immutable, for example.
For now, the functionality is in the CLI library. I'm not sure if we
want to move it into the library crate. I'm leaning towards letting
library users do whatever they want without being restricted by
immutable commits. I do think we should move the functionality into a
future `ui-lib` or `ui-util` crate. That crate would have most of the
functionality in the current `cli_util` module (but in a
non-CLI-specific form).
I'm going to make this function check against a configurable revset
indicating immutable commits. It's more efficient to do that by
evaluating the revset only once.
We may want to have a version of the function where we pass in an
unevaluated revset expression. That would allow us to error out if the
user accidentally tries to rebase a large set of commits, without
having to evaluate the whole set first.
Once we add support for immutable commits, `jj duplicate` should be
allowed to create duplicate of them. The reason it can't duplicate the
root commit is that it would mean there would be multiple root
commits, which would break the invariant that the single root commit
is the only root commit (and the backends refuse to write a commit
without parents). So let's have `jj duplicate` check specifically that
the user doesn't try to duplicate the root commit instead.
For `jj split --interactive`, the user will want to select changes from a subset of files. This means that we need to pass the `Matcher` object when materializing the list of changed files. I also updated the parameter lists so that the matcher always immediately follows the tree objects.
