I want to fix error propagation before I start using async in this
code. This makes the diff iterator propagate errors from reading tree
objects.
Errors include the path and don't stop the iteration. The idea is that
we should be able to show the user an error inline in diff output if
we failed to read a tree. That's going to be especially useful for
backends that can return `BackendError::AccessDenied`. That error
variant doesn't yet exist, but I plan to add it, and use it in
Google's internal backend.
I'm going to add `MergedTreeValue` as an alias for
`Merge<Option<TreeValue>>`, but we already have a type by that name in
`merged_tree`. This patch renames it away, to make room for the new
alias. I used `MergedTreeVal` for this borrowing version to be a bit
like how `str` is a borrowed version of `String`.
Resolves states are most common and the current format is pretty
verbose. Let's print it as if `Merge` were an enum with `Resolved` and
`Conflicted` variants instead.
We need to let async-ness propagate up from the backend because
`block_on()` doesn't like to be called recursively. The conflict
materialization code is a good place to make async because it doesn't
depends on anything that isn't already async-ready.
This means that the commits previously pinned by remote branches are no longer
abandoned. I think that's more correct since "push" is the operation to
propagate local view to remote, and uninteresting commits should have been
locally abandoned.
Since pushed remote branches will share the common base targets with locals,
these branches should be marked as tracking. git::push_branches() will handle
that. It looks ugly that the public GitBranchPushTargets type keeps "force"-d
branches as a separate set, but we'll need to rework that anyway when we
implement --force-with-lease behavior. So let's leave it for now.
Some of the git::push_updates() tests have been migrated to the new function.
I left a couple of basic tests for git::push_updates() because push_updates()
will be used to implement a low-level "jj git push-refs" command.
I made import_refs() not preserve commits referenced by remote branches at
520f692a46 "git: on import_refs(), don't preserve old branches referenced by
remote refs." The idea is that remote branches are weak, and commits referenced
by these refs can be freely rewritten by future local changes without moving
the refs. I don't think that's wrong, but 520f692a46 also made "new" remote
changes be abandoned by old remote refs. This problem occurs only when
git.auto-local-branch is off.
I think there are two ways to fix the problem:
a. pin non-tracking remote branches just like local refs
b. pin newly fetched refs in addition to local refs
This patch implements (b) because it's simpler and more obvious that the
fetched commits would never be abandoned immediately.
This add support for custom `jj` binaries to use custom working-copy
backends. It works in the same way as with the other backends, i.e. we
write a `.jj/working_copy/type` file when the working copy is
initialized, and then we let that file control which implementation to
use (see previous commit).
I included an example of a (useless) working-copy implementation. I
hope we can figure out a way to test the examples some day.
This makes `Workspace::load()` look a new `.jj/working_copy/type` file
in order to load the right working copy implementation, just like
`Repo::load()` picks the right backends based on `.jj/store/type`,
`.jj/op_store/type`, etc. We don't write the file yet, and we don't
have a way of adding alternative working copy implementations, so it
will always be `LocalWorkingCopy` for now.
Our internal working copy implementations at Google will need the
commit so they can walk history backwards until they get to a "public"
commit. They'll then use that to tell build tools and virtual file
systems to present that as a base.
I'm not sure if we'll need to update `reset()` too. It's currently
only used by `jj untrack`, which doesn't change the commit's parent,
so it wouldn't affect any history walks.
`ReadonlyRepo::init()` takes callbacks for initializing each kind of
backend. We called these things like `op_store_initializer`. I found
that confusing because it is not a `OpStoreFactory` (which is for
loading an existing backend). This patch tries to clarify that by
renaming the arguments and adding types for each kind of callback
function.
The state field isn't saved yet. git import/export code paths are migrated,
but new tracking state is always calculated based on git.auto-local-branch
setting. So the tracking state is effectively a global flag.
As we don't know whether the existing remote branches have been merged in to
local branches, we assume that remote branches are "tracking" so long as the
local counterparts exist. This means existing locally-deleted branch won't
be pushed without re-tracking it. I think it's rare to leave locally-deleted
branches for long. For "git.auto-local-branch = false" setup, users might have
to untrack branches if they've manually "merged" remote branches and want to
continue that workflow. I considered using git.auto-local-branch setting in the
migration path, but I don't think that would give a better result. The setting
may be toggled after the branches got merged, and I'm planning to change it
default off for better Git interop.
Implementation-wise, the state enum can be a simple bool. It's enum just
because I originally considered to pack "forgotten" concept into it. I have
no idea which will be better for future extension.
It's going to be easier to define a `LockedWorkingCopy` trait if it
doesn't need to borrow from `WorkingCopy`, so let's remove the
reference we currently have and have
`LockedLocalWorkingCopy::finish()` return the new `LocalWorkingCopy`
instead.
I think the main disadvantage is that we now have to remember to
replace the old `LocalWorkingCopy` instance by the new one, whereas
the compiler would remind us before this commit. We could make
`start_modification()` take an owned `self`, but that would be a bit
annoying to work with when we have the instance stored in a field.
I'm about to make `LockedLocalWorkingCopy` not borrow from
`LocalWorkingCopy`. That will make it easier to forget to update any
`LocalWorkingCopy` variables when the modifications have been
committed. This patch introduces a wrapper around
`LockedLocalWorkingCopy` to help prevent that.
Thanks to Yuya for the suggestion.
`LocalWorkingCopy::check_out()` can be expressed using the planned
`WorkingCopy` trait, so it doesn't need to be in the trait itself
`WorkingCopy`. I wasn't sure if I should make it a free function in
`working_copy`, but I ended up moving it onto `Workspace`.
Since set_remote_branch_target() is called while merging refs, its tracking
state shouldn't be reinitialized. The other callers are migrated to new setter
to keep the story simple.
This isn't important, but I'm going to change remote_targets to store RemoteRef
instead of RefTarget, so I went ahead and change the other field types as well.
There's a subtle behavior change. Unlike the original remove_remote_branch(),
remote_views entry is not discarded when the branches map becomes empty. The
reasoning here is that the remote view can be added/removed when the remote
is added/removed respectively, though that's not implemented yet. Since the
serialized data cannot represent an empty remote, such view may generate
non-unique content hash.
get_branch() would need to reconstruct the remote_targets map if we migrate
the underlying data structure to per-remote views. Let's remove the method as
it is only used in tests.
It seems pretty clear from the context. Turns out we only use the
function in a test case. Maybe we don't even need it. It's easy to
provide it, though.
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.
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.
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 ran into a bug the other day where `jj status` said there was a
conflict in a file but there were no conflict markers in the working
copy. The commit was created when I squashed a conflict resolution
into the commit's parent. The rebased child commit then ended up in
this state. I.e., it looked something like this before squashing:
```
C (no conflict)
|
| B conflict
|/
A conflict
```
The conflict in B was different from the conflict in A. When I
squashed in C, jj would try to resolve the conflicts by first creating
a 7-way conflict (3 from A, 3 from B, 1 from C). Because of the exact
content-level changes, the 7-way conflict couldn't be automatically
resolved by `files::merge()` (the way it currently works
anyway). However, after simplifying the conflict, it could be
resolved. Because `MergedTree::merge()` does another round of conflict
simplification of the result at the end of the function, it was the
simplifed version that actually got stored in the commit. So when
inspecting the conflict later (e.g. in the working copy, as I did), it
could be automatically resolved.
I think there are at least two ways to solve this. One is to call
`merge_trees()` again after calling `tree.simplify()` in
`MergedTree::merge()`. However, I think it would only matter in the
case of content-level conflicts. Therefore, it seems better to make
the content-level resolution solve this case to start with. I've done
that by simplifying the conflict before passing it into
`files::merge()`. We could even do the fix in `files::merge()`, but
doing it before calling it has the advantage that we can avoid reading
some unchanged content from the backend.
I don't think the backend should matter for any of these tests, so
let's test with only one, and let's make that the strictest one - the
new test backend.
This reduces the number of tests by 74 (from 974 to 900), but saves no
measurable run time.
