I had initially hoped that the type-safety provided by the separate
`FileRepoPath` and `DirRepoPath` types would help prevent bugs. I'm
not sure if it has prevented any bugs so far. It has turned out that
there are more cases than I had hoped where it's unknown whether a
path is for a directory or a file. One such example is for the path of
a conflict. Since it can be conflict between a directory and a file,
it doesn't make sense to use either. Instead we end up with quite a
bit of conversion between the types. I feel like they are not worth
the extra complexity. This patch therefore starts simplifying it by
replacing uses of `FileRepoPath` by `RepoPath`. `DirRepoPath` is a
little more complicated because its string form ends with a '/'. I'll
address that in separate patches.
I thought I had looked for this case and cleaned up all the places
when I made `Transaction::commit()` return a new `ReadonlyRepo`. I
must have forgotten to do that, because there we tons of places to
clean up left.
This commit rewites the divergence-resolution part of `evolve()` as an
iterator (though not implementing the `Iterator` trait). Iterators are
just much easier to work with: they can easily be stopped, and errors
are easy to propagate. This patch therefore lets us propagate errors
from writing to stdout (typically pipe errors).
I've wanted the API to look like this for a while. It seems like a
good API to me. It means that the caller won't have to reload the repo
after committing. The cost seems relatively small. It involves copying
potentially a lot of data in memory (at least the View object), but it
shouldn't involve reading from disk or any other processing. To reduce
the amount of data to copy, it may be worth switching to persistent
data types. I've also wanted to do that for the copying we do when
start a transaction.
I couldn't measure any slowdown caused by this change.
The git.git repo seems to have lots of merges from far back in the
history into newer history. That results in `jj log -r 'git_refs()'`
being completely useless because of the number of such edges. For
example, v2.31.0 has almost 600 edges going out of it and presumably
merging (forking) back into various different previous versions. Git,
unlike Mercurial, seems to remove an edge from the graph if the edge
can also be reached via a longer path. This commit makes it so we also
do that (i.e. the filtered graph is a transitive reduction of the
graph before filtering).
This slows down `jj log -r ,,v2.0.0 -T ""` by about 2%. That's still
small enough that it doesn't seem worth it to have a separate iterator
for contiguous ranges (which would be an option).
When rendering a non-contiguous subset of the commits, we want to
still show the connections between the commits in the graph, even
though they're not directly connected. This commit introduces an
adaptor for the revset iterators that also yield the edges to show in
such a simplified graph.
This has no measurable impact on `jj log -r ,,v2.0.0` in the git.git
repo.
The output of `jj log -r 'v1.0.0 | v2.0.0'` now looks like this:
```
o e156455ea491 e156455ea491 gitster@pobox.com 2014-05-28 11:04:19.000 -07:00 refs/tags/v2.0.0
:\ Git 2.0
: ~
o c2f3bf071ee9 c2f3bf071ee9 junkio@cox.net 2005-12-21 00:01:00.000 -08:00 refs/tags/v1.0.0
~ GIT 1.0.0
```
Before this commit, it looked like this:
```
o e156455ea491 e156455ea491 gitster@pobox.com 2014-05-28 11:04:19.000 -07:00 refs/tags/v2.0.0
| Git 2.0
| o c2f3bf071ee9 c2f3bf071ee9 junkio@cox.net 2005-12-21 00:01:00.000 -08:00 refs/tags/v1.0.0
| |\ GIT 1.0.0
```
The output of `jj log -r 'git_refs()'` in the git.git repo is still
completely useless (it's >350k lines and >500MB of data). I think
that's because we don't filter out edges to ancestors that we have
transitive edges to. Mercurial also doesn't filter out such edges, but
Git (with `--simplify-by-decoration`) seems to filter them out. I'll
change it soon so we filter them out.
This adds a `git_refs()` revset that includes all commits pointed to
by a git ref. It's not very useful yet because the graph log doesn't
use the right type of edges for non-contiguous commits.
This lets you use the same operator as we currently have for ancestors
and descendants (`,,`) to also specify a DAG range. That's what
Mercurial uses the `::` operator for and what Git has `git log
--ancestry-path` for.
I really liked the idea of having the operators for parents and
ancestors (etc.) look similar, but that turned out to be problematic
when we want to add an infix operator for a DAG range (hg's `::`
revset operator and git's `--ancestry-path` flag). Let's say we chose
`:*:` as the operator. Part of the problem is how to parse `foo:*:bar`
without eagerly parsing the `foo:`. It would also be nicer to use
exactly the same operator as prefix, postfix, and infix. Since the
"parents" operator can be repeated, we can't have it be just `:` and
the "ancestors" operator be `::`. We could make the "ancestors"
operator be something like `*:*` (or anything symmetric with the `:`
symbol on the inside). However, at that point, the operator is getting
ugly and hard to type. Another option would be to use `:` for
ancestors and `::` for parents, but that is counterintuitive and get
annoying if you want to repeat it. So it seems that the best option is
to simply pick different symbols for parents/children and
ancestors/descendants/range.
This patch changes the ancestors/descendants operators to both be
`,,`. I'm not at all attached to that particular symbol. I suspect
we'll change it later.
This adds `children(<set>)` and `<set>:` for the children of the given
set, and `descendants(<set>)` and `<set>:*` for the descendants of the
given set. The children and descendants are filtered to be among
ancestors of non-obsolete commits. I haven't added a way of overriding
that yet.
The tests don't need any complex set up (no repo necessary), so they
can be in the `revset` module itself. I'm sure we'll need to split up
that module later (at least separate out the parsing), but that's a
separate problem.
This change adds a `non_obsolete_heads(<set>)` revset, which walks up
ancestors of the input set until it gets to a non-obsolete and
non-pruned commit. That's what we do by default in `jj log`
(i.e. without `--all`). Now we can make `jj log` use revsets and teach
it a `-r` option!
This adds `parents(foo)` and `ancestors(foo)` as alternative ways of
writing `:foo` and `*:foo`.
I haven't added support for for whitespace yet; the parsing is very
strict. The error messages will also need to be improved later.
This patch adds initial support for a DSL for specifying revisions
inspired by Mercurial's "revset" language. The initial support
includes prefix operators ":" (parents) and "*:" (ancestors) with
naive parsing of the revsets. Mercurial uses postfix operator "^" for
parent 1 just like Git does. It uses prefix operator "::" for
ancestors and the same operator as postfix operator for descendants. I
did it differently because I like the idea of using the same operator
as prefix/postfix depending on desired direction, so I wanted to apply
that to parents/children as well (and for
predecessors/successors). The "*" in the "*:" operator is copied from
regular expression syntax. Let's see how it works out. This is an
experimental VCS, after all.
I've updated the CLI to use the new revset support.
The implementation feels a little messy, but you have to start
somewhere...
This actually seems to make it slightly slower, but it fixes an
important bug (we used to evolve only one topological branch per `jj
evolve` call). The slowdown seemed to be on the order of 5% when
evolving 100 commits on git.git's "what's cooking" branch.
I suspect that at least one reason that I didn't make
`MutableRepo::base_repo` by an `Arc<ReadonlyRepo>` before was that I
thought that that would mean that `start_transaction()` would need be
moved off of `ReadonlyRepo` so it can be given an
`&Arc<ReadonlyRepo>`, which would make it much less convenient to
use. It turns out that a `self` argument can actually be of type
`&Arc<ReadonlyRepo>`.
