When there's a single parent, we can determine if a commit is empty by
just comparing the tree ids. Also, when using tree-level conflicts, we
don't need to read the trees to determine if there's a conflict. This
patch adds both of those fast paths, speeding up `jj log -r ::main`
from 317 ms to 227 ms (-28.4%). It has much larger impact with our
cloud-based backend at Google (~5x faster).
I made the same fix in the revset engine and the Git push code (thanks
to Yuya for the suggestion).
I think this is less surprising than falling back to the default length.
i64-to-usize conversion can also overflow on 32 bit environment, but I'm not
bothered to handle overflow scenario.
Similar to other boolean flags, such as "working_copy" or "empty".
We could test something like
`"0000000000000000000000000000000000000000".contains(commit_id)`
like I did for myself, but first of all this is ugly, and secondly the root
commit id is not guaranteed to be 40 zeroes as custom backend implementations
could have some other root.
Summary: In preparation for unifying all workspace dependencies across all
crates, let's go ahead and move the jj-cli crate into its own new directory.
This will also be a nicer and more uniform layout as we add new `jj-*` crates.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Change-Id: Icf94e7ae5f290dc8e181215727b38ada
