Git doesn't have a root commit, so we should skip branches pointing to
it on export, just like we do with conflicted branches (which Git also
doesn't support).
Before this patch, the order would depend on the reason we failed to
export a ref, because we would add to the `failed_branches` list in
several different places. What's worse, when the export failed because
the branch was conflicted or had an invalid name (from Git's
perspective), it was non-deterministic because we iterated over a
HashSet. This patch fixes that by sorting at the end.
Note that we still want the `branches_to_update` map to be a
`BTreeMap` so we update branches in deterministic order. Otherwise the
error when trying to export both branches `main` and `main/sub` will
become non-deterministic.
Suppose "x::y" is the operator that defaults to "root()::visible_heads()"
respectively, "::" is identical to "all()". Since we've just changed the
behavior of "..y", ".." is now "root()..visible_heads()" meaning "~root()".
I was looking into some overly verbose logs and happened to notice
that `Store` uses the default derived, which presumably means it's
going to include all objects in its cached. Just including the
backend's debug string seems enough.
In `LockedWorkingCopy::drop()`, we panic if the caller had not called
`finish()`. IIRC, the idea was both to find bugs where we forgot to
call `finish()` and to prevent continuing with a modified
`WorkingCopy` instance. I don't think the former has been a problem in
practice. It has been a problem in practice to call `discard()` to
avoid the panic, though. To address that, we can make the `Drop`
implementation discard the changes (forcing a reload of the state if
the working copy is accessed again).
When restoring (`jj restore`) a 3-sided conflict from one tree into a
2-sided tree (or a resolved tree), we'll need to extend the size arity
of the target tree to that of the source tree. I had not considered
this case before. This patch relaxes the constraint in
`MergedTreeBuilder` to allow such cases. The additional trees are
based on empty trees with only the larger overrides in them.
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.
When we start writing tree-level conflicts in an existing repo, we
don't want commits that change the format to be non-empty if they
don't change any content. This patch updates `MergeTreeId::eq()` to
consider two resolved trees equal even if only their `MergedTreeId`
variant is different (one is path-level and one is tree-level).
I think I've gone through all places we compare tree ids and checked
that it's safe to compare them this way. One consequence is that
rebasing a commit without changing the parents (typically
auto-rebasing after `jj describe`) will not lead to the tree id
getting upgraded, due to an optimization we have for that case. I
don't think that's serious enough to handle specially; we'll have to
support the old format for existing repos for a while regardless of a
few commits not getting upgraded right away.
The number of failing tests with the config option enabled drop from
108 to 11 with this patch.
We're finally ready to start writing trees using the new format where
we represent conflicts by having multiple trees in the commit instead
of having a single tree with multiple entries at a path. This patch
adds a config option for that. It's not ready to be used yet, so I
haven't updated the release notes or other documentation.
I added only a simple CLI test for testing what happens when the
config is enabled in an existing repo. 108 tests currently fail if we
flip the default.
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.
I made it simply fail on explicit fetch/import, and ignored on implicit import.
Since the error mode is predictable and less likely to occur. I don't think it
makes sense to implement warning propagation just for this.
Closes#1690.
With the already existing `MergedTree::resolve()` and all the recent
refactorings into `Merge<T>`, it's now very easy to add support for
3-way merging of `MergedTree` instances.
