Empty files can be confusing in diff output. For example:
```
Added regular file file1:
Added regular file file2:
1: foo
```
This commit adds an "(empty)" placeholder instead. Since it's not
colored, and doesn't have line numbers, it will hopefully not be
mistaken for a file with the contents "(empty)".
I think I moved way too many functions onto `Merge<Option<TreeValue>>`
in 82883e648da4. This effectively reverts almost all of that
commit. The `Merge<T>` type is simple container and it seems like it
should be at fairly low level in the dependency graph. By moving
functions off of it, we can get rid of the back-depdencies from the
`merge` module to the `conflict` module that I introduced when I moved
`Merge` to the `merge` module. I'm thinking the `conflict` module can
focus on materialized conflicts.
Two things will be added:
a. show warning if child exited with non-zero status
b. attach pager stdin to stderr of child process
I think (a) could be propagated from generate_diff() as an error variant, but
for (b), it makes sense to pass ui down to the function.
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
