Allow --output to be a directory

[shreyasminocha]

Currently, when the --output flag to torrent create is a directory, imdl errors out with "error: Output path already exists".

With this change, it will create a torrent file with the default name, but in the specified directory.

$ mkdir out
$ imdl torrent create src --output out
[1/3] 🧿 Searching `src` for files…
[2/3] 🧮 Hashing pieces…
[3/3] 💾 Writing metainfo to `out/src.torrent`…
✨✨ Done! ✨✨
$ ls out
src.torrent

Resolves #525

[casey]

Nice! This should re-use CreateContent::torrent_path to set the filename, and also needs a test.

[shreyasminocha]

This should re-use CreateContent::torrent_path to set the filename

I tried that, but it seems to return an absolute path, and path.join(absolute_path) effectively just returns absolute_path. I could edit torrent_path to return the relative path "{name}.torrent" if you prefer.

[shreyasminocha]

I added a test, but it's currently failing because path.is_dir() returns false in the test env. Not sure what's up with that; I could be misunderstanding how temptree works.

[casey]

I believe this check is failing:

intermodal/src/subcommand/torrent/create.rs

Line 340 in 7812ad2

if !self.force && path.exists() {

[shreyasminocha]

This should be ready for review, unless you'd like me to change torrent_path as described in #546 (comment)! Let me know if this needs to be rebased.

[casey]

LGTM!