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
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.
previously, `jj diff` would show the full contents of binary files such as images.
after this change, it instead shows "(binary)". it still shows the filename and metadata so that
users can open the file in the viewer of their choce.
future work could involve showing binary files as Sixel or similar; finding a way to compare large
non-binary files without filling up the screen; or extending the data backends to avoid having to
read the whole file contents into memory.
Note that one of the new tests panics; this is a newly discovered bug.
In Git, a commit's direct parent is allowed to also be an indirect ancestor
at the same time. `jj` currently tries to prevent this situation, but does
allow it. The correctness of `rebase -r A -d descendant_of_A` currently depends
on this jj-specific behavior; we should change that.
Cc #2600
On my Debian laptop, openssl_init() takes ~30ms to load the default CA
certificates serialized in PEM format, and the cost is added to each jj
invocation. This change saves 20s (of 50s) on my machine.
% wc -l /usr/lib/ssl/cert.pem
3517 /usr/lib/ssl/cert.pem
