After the previous commit, `MergedTree` and `MergedTreeId` are almost
identical, with the only difference being that `MergedTree` is attached
to a `Store` instance. `MergedTreeId` is also equivalent to
`Merge<TreeId>`, since it is just a wrapper around it.
In the future, `MergedTree` might contain additional metadata like
conflict labels. Therefore, I replaced `MergedTreeId` with `MergedTree`
wherever I think it would be required to pass this additional metadata,
or where the additional methods provided by `MergedTree` would be
useful. In any remaining places, I replaced it with `Merge<TreeId>`.
I also renamed some of the `tree_id()` methods to `tree_ids()` for
consistency, since now they return a merge of individual tree IDs
instead of a single "merged tree ID". Similarly, `MergedTree` no longer
has an `id()` method, since tree IDs won't fully identify a `MergedTree`
once it contains additional metadata.
Currently, creating a `MergedTree` requires reading all of its root
trees from the store. However, this is often not actually required. For
instance, if the only reason to read the trees is to call
`MergedTree::merge`, and the merge is trivial, then there was no need to
read the trees. Changing `MergedTree` to only require a `Merge<TreeId>`
instead of a `Merge<Tree>` will make it possible to avoid reading trees
unnecessarily in these cases.
One benefit of this approach is that `Commit::tree` no longer requires
reading from the store, so it can be made synchronous and infallible,
which simplifies a lot of code.
This will allow us to "touch" change id without duplicating commits.
The caller should also do .generate_new_change_id() to not make commits
divergent. This function could do that automatically, but I'm not sure if that's
good. Alternatively, we can add mut_repo.duplicate_commit(predecessor), but
we'll need to refactor CommitRewriter.
This can happen if we remove predecessors from the commit object, and if
committer timestamp wasn't updated (like in some jj-lib tests.) It's not wrong
for the store to "overwrite" existing objects, but the repo expects
new/rewritten commits have unique ids. If they didn't, cycle would be created in
mut_repo.commit_predecessors/parent_mapping.
There are two major goals:
1. garbage-collect predecessor commits referenced by immutable commits.
2. show operations alongside predecessors in "jj evolog".
The predecessors field will be removed from the Commit object. Maybe we can
also remove (writer side of) the extras table from GitBackend.
"jj evolog" will traverse the operation history to build an evolution
graph. This will be slower than the current implementation, but it seems
tolerable for mid-size repository stored in a local disk.
(when the page cache is warm)
% time jj op log -T'"."' --no-graph | wc -c
50459
jj op log -T'"."' --no-graph 0.12s user 0.31s system 103% cpu 0.418 total
Suppose we're interested in recent modifications, the traversal can often be
terminate early. I also have an idea for indexing originating operations.
https://github.com/jj-vcs/jj/pull/6405
For old operations which didn't record predecessors, "jj evolog" will fall back
to commit.predecessor_ids(). That's why commit_predecessors is Option<_>.
I'm going to remove the settings argument from start_transaction(),
new_commit(), and rewrite_commit(), and these functions will use the settings
passed in to the constructor.
It's nice that "jj config list --include-defaults" can show these default
values.
I just copied the jj-cli directory structure, but it's unlikely we'll add more
config/*.toml files.
The current implementation is silly, which will be reimplemented to be using
toml_edit::DocumentMut. "jj config set" will probably be ported to this API.
UserSettings::get_*() will be changed to look up a merged value from
StackedConfig, not from a merged config::Value. This will help migrate away
from the config crate.
Not all tests are ported to ConfigLayer::parse() because it seemed a bit odd
to format!() a TOML document and parse it to build a table of configuration
variables.
We had both `repo()` and `mut_repo()` on `Transaction` and I think it
was easy to get confused and think that the former returned a
`&ReadonlyRepo` but both of them actually return a reference to
`MutableRepo` (the latter obviously returns a mutable reference). I
hope that renaming to the more idiomatic `repo_mut()` will help
clarify.
We could instead have renamed them to `mut_repo()` and
`mut_repo_mut()` but that seemed unnecessarily long. It would better
match the `mut_repo` variables we typically use, though.
I plan to provide a richer version of `TreeDiffEntry` with copy info
(and to make `TreeDiffEntry` itself "poorer"). Most callers want to
know about copies/renames, but at least working copy implementations
probably don't. This patch adds separate `diff_stream()` and
`diff_stream_with_copies()` so we can provide the simpler interface
for callers that don't need copy info.
It's common to create empty working-copy commits while using jj, and
currently the author timestamp for a commit is only set when it is first
created. If you create an empty commit, then don't work on a repo for a
few days, and then start working on a new feature without abandoning the
working-copy commit, the author timestamp will remain as the time the
commit was created rather than being updated to the time that work began
or finished.
This commit changes the behavior so that discardable commits (empty
commits with no description) by the current user have their author
timestamps reset when they are rewritten, meaning that the author
timestamp will become finalized whenever a commit is given a description
or becomes non-empty.
The function now returns an iterator over `Result`s, matching
`Operation::parents()`.
I updated callers to also propagate the error where it was trivial.
I'm going to add try_from_hex(), which requires Self: Sized. Such trait bound
could be added, but I don't think we'll need abstracted ObjectId constructors
at all.
I'm going to add a prefix resolution method to OpStore, but OpStore is
unrelated to the index. I think ObjectId, HexPrefix, and PrefixResolution can
be extracted to this module.
This removes uses of `DescendantRebaser::new` or
`MutRepo::create_descendant_rebaser` from most tests. The exceptions are the
tests having to do with abandoning empty commits on rebase, since adjusting
those is a bit more elaborate (see follow-up commits).
It seems better to have the caller pass the transaction description
when we finish the transaction than when we start it. That way we have
all the information we want to include more readily available.
This enables cheap str-to-RepoPath cast, which is useful when sorting and
filtering a large Vec<(String, _)> list by using matcher for example. It
will also eliminate temporary allocation by repo_path.parent().
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.
It makes the call sites clearer if we pass the `TestRepoBackend` enum
instead of the boolean `use_git` value. It's also more extensible (I
plan to add another backend for tests).
Many (most?) callers of `Store::empty_tree_id()` really want a
`MergedTreeId`, so let's create a helper for that. It returns the
`Legacy` variant, which is what all current callers used. That should
be all we need since the two variants compare equal these days, and
since trees built based on the legacy variant can get promoted to the
new variant on write if the config is enabled.
I think most tests want a `MergedTree`, so this makes `create_tree()`
return that. I kept the old function as `create_single_tree()`. That's
now only used in `test_merge_trees` and `test_merged_tree`.
I also consistently imported the functions now, something I've
considered doing for a long time.
