This prepares `jj status` for working better on an old repo state
(with `--at-op`). When looking at an old repo state, the "working
copy" should reflect the state from that state, i.e. the view's
"checkout", not the current working copy.
Before this patch, `jj log` would always commit the working copy and
most other commands would commit the working copy only if they were
passed a revset of exactly "@". This patch makes it so they all commit
the working copy unless they are passed just a symbol other than "@"
(typically a commit id). That means that we will not commit the
working copy if the user does `jj diff -r abc123`, but we will if they
do `jj diff -r :abc123`. It's clearly unnecessary in both those cases,
and we should fix, but this is probably good enough for now.
This patch adds checks in all (?) commands that rewrite commits to
make sure the commit they're about to rewrite is allowed to be
rewritten. The only check we do is that it's not a root commit. We
should at least add checks for public commits later.
Now that we auto-evolve after most operations, the user may not know
what "evolve" means. Even before that, the way `jj evolve` resolved
orphans after pruning was by rebasing them.
The project is starting to work well enough that I think it's time
that the documentation targets users instead of VCS hackers. This
patch rewrites much of the README to describe how the features help
the user instead of describing how they work. It also adds a tutorial.
Perhaps it makes more sense to display the working copy commit just
above the changes in the working copy commit, even though that means
that the order between the working copy commit and the parent becomes
the opposite of the order in `jj log`.
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.
If you ran two concurrent `jj describe` (for example) before this
patch, they'd both try to open an editor on the same file. This patch
fixes that by randomizing the filename. It also deletes the file at
the end so the `.jj/` directory is not cluttered by these files.
It's annoying to have to run run `jj evolve`, and it's easy to forget
(especially after updating the description of the working copy
parent), so let's just always do it. Unlike most VCSs, we don't have
to worry about merge conflicts since we can represent them in commits.
