This is part of a series of changes to make most methods on index traits
(i.e. `ChangeIdIndex`, `MutableIndex`, `ReadonlyIndex`, `Index`)
fallible. This will enable networked implementations of these traits,
which may produce I/O errors during operation. See #7825 for more
information.
In this implementation, we assume that predecessor commits created by old jj are
reachable from at least one of the historical views. However, there are a couple
of commands which create transitive predecessors. For example, "jj squash" into
grandparent will rebase a rewritten source, so the pre-rebase source commit
won't be visible to any views. To work around the problem, all immediate
predecessors of historically visible commits are also preserved.
Note that this change should be considered forward-incompatible change. The
stored commits may have unreachable predecessors once we run "jj op abandon &&
jj util gc".
WalkPredecessors::flush_commits() doesn't need to guard against unreachable
commits. I was wondering whether values (or old ids) of op.commit_predecessors
map should be preserved, and I decided to keep both keys and values. It's nice
that we can get rid of index.has_id() calls when we drop support for legacy
commit.predecessors.
There are a couple of hand-rolled implementations of roots..heads query, and I'm
going to add one more. It's wasteful to test these one by one.
The added iterator will have to scan roots::heads range eagerly instead of
::roots. I think this is good for typical use cases where roots are closer to
heads than the root().
Operation ids in test_op_abandon*() are changed because reparented operations
now preserve the predecessors mapping.
Since this patch will affect whether "jj evolog" can show the associated
operations, I added a changelog entry. It's still a bit vague, but I think we
can add a more detailed explanation later.
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<_>.
We don't want to derive `PartialEq` on `OpsetResolutionError` because we may need an
`Other` variant in the future that wraps a type without a `PartialEq` implementation.
Pattern-matching is used instead to assert the contents.
We can usually omit quotes in --config=NAME=VALUE, but an RFC3339 string is a
valid TOML date-time expression. It's weird that quoting is required to specify
a date-time value.
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.
This removes an invalid View state from the root operation.
Note that the root index will have to be reindexed in order to resolve "root()"
in the root operation. I don't think this would practically matter, so this
patch doesn't bump the index version to invalidate the existing indexes.
See also 48a9f9ef56 "repo: use Transaction for creating repo-init operation."
Jujutsu's branches do not behave like Git branches, which is a major
hurdle for people adopting it from Git. They rather behave like
Mercurial's (hg) bookmarks.
We've had multiple discussions about it in the last ~1.5 years about this rename in the Discord,
where multiple people agreed that this _false_ familiarity does not help anyone. Initially we were
reluctant to do it but overtime, more and more users agreed that `bookmark` was a better for name
the current mechanism. This may be hard break for current `jj branch` users, but it will immensly
help Jujutsu's future, by defining it as our first own term. The `[experimental-moving-branches]`
config option is currently left alone, to force not another large config update for
users, since the last time this happened was when `jj log -T show` was removed, which immediately
resulted in breaking users and introduced soft deprecations.
This name change will also make it easier to introduce Topics (#3402) as _topological branches_
with a easier model.
This was mostly done via LSP, ripgrep and sed and a whole bunch of manual changes either from
me being lazy or thankfully pointed out by reviewers.
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.
It should be useful at least in the presentation layer to know which
operations correspond to working-copy snapshots. They might be
rendered differently in the graph, for example. Or maybe an undo
command wants to warn if you just undid a snapshot operation. This
patch just introduces a field in the metadata to store the
information.
The `ContentHash` documentation specifies that implementations for enums should
hash the ordinal number of the variant contained in the enum as a 32-bit
little-endian number and then hash the contents of the variant, if any.
The current implementations for `std::Option`, `MergedTreeId`, and
`RemoteRefState` are non-conformant since they hash the ordinal number as a u8
with platform specific endianness.
Fixes#3051
It seems obvious in hindsight to have a virtual root operation just
like we have a virtual root commit. It removes the same kind of
problems by making sure there's always a common ancestor (or multiple)
between any two commits.
I think the reason I didn't add a root operation from the beginning
was that there used to be a mandatory working-copy commit in the view
(this was before support for multiple workspaces).
Perhaps we should remove the "initialize repo" operation now. The only
difference between their view objects is that the "initialize repo"
operation adds the root commit as a head. We could add that to the
root operation, but then the root operation's value depends on the
commit backend.
We've had the public_heads for as long as we've had the View object,
IIRC (I didn't check), but we still don't use it for anything. I don't
have any concrete plans for using it either. Maybe our config for
immutable commits is good enough, or maybe we'll want something more
generic (like Mercurial's phases). For now, I think we should simplify
by removing it the storage for public heads.
Since new operations and views may be added concurrently by another process,
there's a risk of data corruption. The keep_newer parameter is a mitigation
for this problem. It's set to preserve files modified within the last 2 weeks,
which is the default of "git gc". Still, a concurrent process may replace an
existing view which is about to be deleted by the gc process, and the view
file would be lost.
#12
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 will be used in "jj op abandon ..op_id" command. The "op_id..@" range will
be reparented onto the root operation.
The current implementation is good enough for local repos, but it won't scale.
We might want to extract it as a trait method or introduce OpIndex for
efficient DAG operation.
A possible use case is when doing some archaeology around a certain operation.
The current implementation is quadratic if + is repeated. Suppose op_id is
usually close to the current op heads, I think it'll practically work better
than building a reverse lookup table.
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.
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).
