Removing dependency to git2

[vsiles]

This is related to #217

git2 is replaced by:

• in buffrs itself, we now call git status --porcelain directly, since gix is not able to give us information about untracked files.
• in the test-suite, we use gix instead of git2

The test suite has been updated to deal with some minor behaviour.

I run time cargo build before/after to compare since build time was an issue, here are the results on my laptop (M3):

• before:

    Finished dev [unoptimized + debuginfo] target(s) in 57.88s

________________________________________________________
Executed in   57.95 secs    fish           external
   usr time  185.65 secs    0.16 millis  185.65 secs
   sys time   55.63 secs    1.15 millis   55.63 secs

• after:

   Finished dev [unoptimized + debuginfo] target(s) in 15.59s

________________________________________________________
Executed in   15.66 secs    fish           external
  usr time  102.08 secs    0.18 millis  102.08 secs
  sys time   12.89 secs    1.19 millis   12.89 secs

[mara-schulke]

Hi, is it possible to use gix for this? If not we can remove the feature altogether. Parsing cli outputs is super error prone and I would like to avoid this.

[vsiles]

As I mention in the issue discussion, gix does not yet allow us to do what git2 was doing: gix does not currently have information about untracked files, so we could only complain if some tracked files have changes.
That being said, I took care of calling git status --porcelain because it is made exactly for that:

--porcelain[=]
Give the output in an easy-to-parse format for scripts. This is similar to the short output, but will remain stable across Git > versions and regardless of user configuration. See below for details.

That leaves as multiple options:

1. we remove this check altogether
2. we use gix and accept to ignore untracked file (for now at least)
3. we use git but don't parse the output. If the output is empty, the repo is clean, otherwise it is not and we print the output as is
4. we trust the --porcelain option and parse the output

I don't have a strong opinion here, so I'll implement what you think is best

[tomkarw]

I agree that using git status --porcelain will be robust enough, so I vote for option 4.

That said, I'm fuzzy on why we care about uncommitted changes in the first place. Maybe it's a chance to skim some overreaching features fat.

[vsiles]

Yes, I think I'm too new to have enough context here ;) I'm leaving that decision to @mara-schulke and you

[mara-schulke]

Okay, so im okay with option 4 but: I would not error when the parsing fails. So I would at most emit a warning here that git could not be found / the output is malformed. Currently your implementation raises errors which would potentially abort the call.

If you make it best-effort (say: skip this and emit a warning line to the user) im okay with using --porcelain! 😊

[vsiles]

Should be good for review now. Thanks for all the input.

[tomkarw]

LGTM, let's merge