This follows up on https://github.com/martinvonz/jj/pull/3459 and adds a
label to the closing delimeter of each conflict, e.g. "Conflict 1 of 3
ends".
I didn't initially put any label at the ending delimeter since the
starting delimeter is already marked with "Conflict 1 of 3". However,
I'm now realizing that when I resolve conflicts, I usually go from top
to bottom. The first thing I do is delete the starting conflict
delimeter. It is when I get to the *end* of the conflict that I wonder
whether there are any more conflicts left in the file.
For example,
```
<<<<<<< Conflict 1 of 3
+++++++ Contents of side #1
left 3.1
left 3.2
left 3.3
%%%%%%% Changes from base to side #2
-line 3
+right 3.1
>>>>>>>
```
or
```
<<<<<<< Conflict 1 of 1
%%%%%%% Changes from base to side #1
-line 3
+right 3.1
+++++++ Contents of side #2
left 3.1
left 3.2
left 3.3
>>>>>>>
```
Currently, there is no way to disable these, this is TODO for a future
PR. Other TODOs for future PRs: make these labels configurable. After
that, we could support a `diff3/git`-like conflict format as well, in
principle.
Counting conflicts helps with knowing whether you fixed all the
conflicts while you are in the editor.
While labeling "side #1", etc, does not tell you the commit id or
description as requested in #1176, I still think it's an improvement.
Most importantly, I hope this will make `jj`'s conflict format less
scary-looking for new users.
I've used this for a bit, and I like it. Without the labels, I would see
that the two conflicts have a different order of conflict markers, but I
wouldn't be able to remember what that means. For longer diffs, it can
be tricky for me to quickly tell that it's a diff as opposed to one of
the sides. This also creates some hope of being able to navigate a
conflict with more than 2 sides.
Another not-so-secret goal for this is explained in
https://github.com/martinvonz/jj/pull/3109#issuecomment-2014140627. The
idea is a little weird, but I *think* it could be helpful, and I'd like
to experiment with it.
When you use e.g. `git switch` to check out a conflicted commit,
you're going to end up with the `.jjconflicts-*` directories in your
working copy. It's probably not obvious what those mean. This patch
adds a README file to the root tree to try to explain to users what's
going on and how to recover.
The authoritative information about conflicts is stored in the
`jj:trees` commit header. The contents of conflicted commits is only
used for preventing GC. We can therefore add contents to the tree
without much consequence.
As discussed in #2900, the milliseconds are rarely useful, and it can
be confusing with different timezones because it makes harder to
compare timestamps.
I added an environment variable to control the timestamp in a
cross-platform way. I didn't document because it exists only for tests
(like `JJ_RANDOMNESS_SEED`).
Closes#2900
We haven't used custom Git commit headers for two main reasons:
1. I don't want commits created by jj to be different from any other
commits. I don't want Git projects to get annoyed by such commit
and reject them.
2. I've been concerned that tools don't know how to handle such
headers, perhaps even resulting in crashes.
The first argument doesn't apply to commits with conflicts because
such commits would never be accepted by a project whether or not they
use custom commit headers. The second argument is less relevant for
conflicted commits because most tools will be confused by such commits
anyway.
Storing conflict information in commit headers means that we can
transfer them via the regular Git wire protocol. We already include
the tree objects nested inside the root-level tree, so they will also
be transferred.
So, let's start by writing the information redundantly to the commit
header and to the existing storage. That way we can roll it back if we
realize there's a problem with using commit headers.
this greatly speeds up the time to run all tests, at the cost of slightly larger recompile times for individual tests.
this unfortunately adds the requirement that all tests are listed in `runner.rs` for the crate.
to avoid forgetting, i've added a new test that ensures the directory is in sync with the file.
## benchmarks
before this change, recompiling all tests took 32-50 seconds and running a single test took 3.5 seconds:
```
; hyperfine 'touch lib/src/lib.rs && cargo t --test test_working_copy'
Time (mean ± σ): 3.543 s ± 0.168 s [User: 2.597 s, System: 1.262 s]
Range (min … max): 3.400 s … 3.847 s 10 runs
```
after this change, recompiling all tests take 4 seconds:
```
; hyperfine 'touch lib/src/lib.rs ; cargo t --test runner --no-run'
Time (mean ± σ): 4.055 s ± 0.123 s [User: 3.591 s, System: 1.593 s]
Range (min … max): 3.804 s … 4.159 s 10 runs
```
and running a single test takes about the same:
```
; hyperfine 'touch lib/src/lib.rs && cargo t --test runner -- test_working_copy'
Time (mean ± σ): 4.129 s ± 0.120 s [User: 3.636 s, System: 1.593 s]
Range (min … max): 3.933 s … 4.346 s 10 runs
```
about 1.4 seconds of that is the time for the runner, of which .4 is the time for the linker. so
there may be room for further improving the times.
I have used the tree-level conflict format for several weeks without
problem (after the fix in 51b5d168ae). Now - right after the 0.10.0
release - seems like a good time to enable the config by default.
I enabled the config in our default configs in the CLI crate to reduce
impact on tests (compared to changing the default in `settings.rs`).
This switches the whole `diff_util` module to working with
`MergedTree`, `Merge<Option<TreeValue>>` etc., so it can support
tree-level conflicts.
Since we want to avoid using `ConflictId`s, I switched the hash we use
for conflicts in `--git` style diffs to use an all-'0' id instead of
using the conflict id.
