The `move_commits` function accepts a set of target commits to shift to
a new location given by `new_parents` and `new_children`. The roots of
the target set will be reparented onto `new_parents`. `new_children`
will then be reparented onto the heads of the target set.
The commits will be rebased in reverse topological order based on the
new set of parents of each commit, which avoids the need for multiple
sets of rebase operations.
This is following on the rewrite for `parallelize`.
- https://github.com/martinvonz/jj/pull/3521
Since rebase_descendants from rebase.rs is no longer used outside of that file,
it can be made private again.
This replaces `.map(|c| c.id().clone())` with `.ids().cloned()` to use nicer
syntax for getting `CommitId`s from an iterator of commits using the
`CommitIteratorExt` trait.
In one case we can actually call `.parent_ids()` directly. I also pluralized a
variable to make it clearer that it's a vec of IDs and not a single ID.
`CommitRewriter` wraps 3 of the arguments, so I think it makes sense
to pass it instead. More importantly, I hope to continue refactoring
so many of the callers already have a `CommitRewriter`.
It's cheap to look up commits again from the cache in `Store` but it
can be expensive to look up commits we didn't end up needing. This
will make it easier to refactor further and be able to cheaply set
preliminary parents for a rewritten commits and then let the caller
update them.
I'm going to add a helper struct to help with rewriting commits. I
want to make that struct own the old commit and the new parents to
simplify lifetimes. This patch prepares for that by passing the
commits by value to `rebase_commit()`.
This function doesn't actually need commits, it only needs their IDs. In some
contexts we may only have commit IDs, so there's no need to require an iterator
of Commits.
This commit also adds a `CommitIteratorExt` that makes it easy to convert an
iterator of `&Commit` to an iterator of `&CommitId`.
resolve_revset_default_single() will be inlined instead. Since "default_single"
evaluation can return multiple revisions, the CLI interface usually accepts
multiple arguments. This suggests that there would be no external callers of
the singular resolve_revset_default_single().
This refactor will allow us to reuse new `rebase_descendants` function for the
`jj split --siblings` feature (#2274) and later possibly for `jj parallelize`
(#1079).
When the caller needs a formatter, it's because they're doing
something non-trivial. When the user passed `--quiet` (see upcoming
patch), we should ideally skip doing related work for print the
formatting output. It helps if the `Ui` object doesn't even return a
`Formatter` then, so the caller is forced to handle the quiet case
differently.
Thanks to Yuya for the suggestion.
One less CLI revset helper. It might look odd that "jj rebase" says "Merge
failed" whereas "jj new" doesn't, but that depends on where the BackendError
is detected.
When we abandon a working-copy commit, we create a new working-copy
commit on top. This behave is very useful, but it's not obvious. Let's
document it.
Thankfully, 2bbefcc3383f (rewrite: default to not simplifying ancestor
merges) means that there are much fewer commands where we need to
document this behavior.
I think the user usually wants to abandon only newly empty commits. I
think they should use `jj abandon` if they want to get rid of already
empty commits. By keeping already empty commits, we don't need to
special-case the working copy and merge commits.
I think I prefer this behavior because it's less lossy. The user can
manually simplify the history with `jj rebase -s <merge commit> -d
<one of the parents>` afterwards. We can roll this change back later
if we find it annoying.
I think the conclusion from #2600 is that at least auto-rebasing
should not simplify merge commits that merge a commit with its
ancestor. Let's start by adding an option for that in the library.
This prevents rust doctests from trying to compile the code blocks.
I don't think we use doctests much or at all, but I'd like
`cargo insta test --test-runner nextest --accept --workspace`
to pass.
Unfortunately, this affects the output of `jj help` as well, but I
can't think of a workaround for that.
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.
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.
Note that one of the new tests panics; this is a newly discovered bug.
In Git, a commit's direct parent is allowed to also be an indirect ancestor
at the same time. `jj` currently tries to prevent this situation, but does
allow it. The correctness of `rebase -r A -d descendant_of_A` currently depends
on this jj-specific behavior; we should change that.
Cc #2600
This follows up on 3967f63 (see that commit's description for more
motivation) and e79c8b6.
In a discussion linked below, it was decided that forbidding `-r --skip-empty`
entirely is preferable to the mixed behavior introduced in 3967f63.
3967f637dc (commitcomment-133539911)
This follows up on @matts1 's #2609.
We still allow the `-r` commit to become empty. I would be more comfortable if
there was a test for that, but I haven't done that (yet?) and it seems pretty
safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely,
since it is far less useful than `-s --skip-empty` or `-b --skip-empty`.
I think it is undesired to abandon emptied descendants. As far as descendants
of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`,
and `jj abandon` does not remove emptied commits. It also doesn't seem very
useful to do that, since I think descendant commits of an abandoned (or moved
with `-r`) commit only become empty in pathological cases.
Additionally, if we did want -r to empty descendants of `A`, we'd have to add
thorough tests and possibly improve the algorithm. I want to refactor `rebase
-r` and add features to it, and having to consider cases of commits becoming
abandoned makes everything harder.
For example, if we have
```
root -> A -> B -> C
```
and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether
the current algorithm will work correctly. It seems possible that it would, but
that depends on the fact that empty merge commits are not abandoned for
descendants. That seems dangerous to rely on without tests.
I hope (but can't promise) that in the near future, making DescendantRebaser
return more information should help make it possible to create such
functionality in a more robust way. I am likely to attempt this as part of
implementing `-r --after`.
`RevsetExpression::resolve()` is meant for programmatically created
expressions. In particular, it may not contain symbols. Let's try to
clarify that by renaming the function and documenting it.
Summary: This is currently used by `new.rs`, `workspace.rs`, and `rebase.rs`,
and may be useful for other commands and custom CLIs. So just go ahead and move
it into the parent module hierarchy.
Also rename the function to `resolve_all_revs`, as it isn't actually specific to
rebase at all.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Change-Id: I0ea12afd8107f95a37a91340820221a0
