If the existing index was corrupt, it would have to be rebuilt while loading a
repo (at least in colocated environment.) Then, the index will be rebuilt again.
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
It doesn't make sense to do gc from a non-head operation because that means
either the head operation would be corrupted or the --at-op argument is
ignored.
We would like to use a non-static version string at Google. We have a
workaround using Lazy, but it seems unfortunate to have to do
that. Using dynamic strings requires Clap's `string` feature, which
increases the binary size by 140 kiB (0.6%).
I'm going to add try_from_hex(), which requires Self: Sized. Such trait bound
could be added, but I don't think we'll need abstracted ObjectId constructors
at all.
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.
In order to implement GC (#12), we'll need to somehow prune old operations.
Perhaps the easiest implementation is to just remove unwanted operation files
and put tombstone file instead (like git shallow.) However, the removed
operations might be referenced by another jj process running in parallel. Since
the parallel operation thinks all the historical head commits are reachable, the
removed operations would have to be resurrected (or fix up index data, etc.)
when the op heads get merged.
The idea behind this patch is to split the "op log" GC into two steps:
1. recreate operations to be retained and make the old history unreachable,
2. delete unreachable operations if the head was created e.g. 3 days ago.
The latter will be run by "jj util gc". I don't think GC can be implemented
100% safe against lock-less append-only storage, and we'll probably need some
timestamp-based mechanism to not remove objects that might be referenced by
uncommitted operation.
FWIW, another nice thing about this implementation is that the index is
automatically invalidated as the op id changes. The bad thing is that the
"undo" description would contain an old op id. It seems the performance is
pretty okay.
This removes CommandError dependency from these resolution functions. We might
want to refactor the error types again if we introduce a real "opset" evaluator.
The error message for unresolved op heads now includes "@" instead of the whole
expression.
The resolver callback usually returns wider error type, which I don't think
is a variant of OpHeadResolutionError.
To help type inference, resolver's error type is E, not E1 where E: From<E1>.
I'll probably add change id lookup methods to CompositeIndex. The Index trait
won't gain resolve_change_id_prefix(), but I also renamed its resolve_prefix()
for consistency.
This requires creating a new public API as a substitute. I took the opportunity
to also add some comments to the
`MutRepo::record_rewritten_commit`/`record_abandoned_commit` functions.
I imade the simplest possible addition to the API; it is not a very elegant
one. Eventually, the entire `record_rewritten_commit` API should probably be
refactored again.
I also added some comments explaining what these functions do.
At some point, I tried `new_commit` instead of `rewrite_commit` in the split
command. That seemed to work, but messed up the dates in a subtle way.
This commit should prevents repeats of this mistake and emphasize the
importance of the author dates being preserved.
This partially reverts 6c627fb30d "cli: default to log when no subcommand is
provided." We could reject an empty alias at all, but we would still need to
ensure that the expanded alias contained a subcommand name.
The help output is a bit odd as the <COMMAND> can be omitted, but I think
that's acceptable. If we do care about that, maybe we can override_usage().
This is basically the same as Mercurial's workaround. I don't know about Git,
but arguments order is very restricted in git, so -C path can be parsed prior
to alias expansion. In hg and jj, doing that would be messy and unreliable.
Closes#2414
It should be better to handle invalid -R path globally. The error message is
a bit worse, but I think it's still okay.
This helps to load temporary config from the cwd-relative path. If the command
processing continued with an invalid -R path, the temporary config would have
to be explicitly discarded.
Make it clearer what the command does, make the error message when the file is
not ignored less of a surprise.
Also, I think it's nice to mention `.git/info/exclude`, since the path is
not trivial to remember.
As far as I can see in the chat, there's no objection to changing the default,
and git.auto-local-branch = false is generally preferred.
docs/branches.md isn't updated as it would otherwise conflict with #2625. I
think the "Remotes" section will need a non-trivial rewrite.
#1136, #1862
This is really a simple change that does the following in a transaction:
* Set the new branch name to point to the same commit as the old branch name.
* Set the old branch name to point to no commit (hence deleting the old name).
Before it starts, it confirms that the new branch name is not already in use.
I originally thought this would be unavoidable, but I was wrong. "jj git clone"
doesn't implicitly create any local branch if git.auto-local-branch is off, and
that's fine because the detached HEAD state is normal in jj.
That being said, Git users would expect that the main/master branch exists.
Since importing the default branch is harmless, let's create and track it no
matter if git.auto-local-branch is off.
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.
