feat: diff source with destination on conflict

[ditsuke]

Fixes #91

Summary

• Source and target are diff-ed when target is modified between deploys
• Diffs are printed, when there are real conflicts.
• In the absence of real conflicts, target is silently updated cutting down
  on false conflict errors.

[SuperCuber]

Looking good! Only need to make the function public so it compiles.

Also, I would remove the info print with the .yellow, that info is already in the error.

[SuperCuber]

One more comment, it makes sense to me to do the diff the other way around. Say someone added a line to the template and you're displaying that you are skipping because of the line, I would expect that line to be green. Right now however it shows the difference that it will apply if a force is requested which kinda makes sense too.

Which one do you think is better? In any case, we should print something like

[ERROR] Updating template "test_in/file" -> "test_out/file" but target contents were changed. Skipping.
    Difference between expected and actual:
    //or
    Refusing to make the following change:
// diff here

[ditsuke]

Looking good! Only need to make the function public so it compiles.

Also, I would remove the info print with the .yellow, that info is already in the error.

Whoops missed staging that!

One more comment, it makes sense to me to do the diff the other way around. Say someone added a line to the template and you're displaying that you are skipping because of the line, I would expect that line to be green. Right now however it shows the difference that it will apply if a force is requested which kinda makes sense too.

Which one do you think is better? In any case, we should print something like

[ERROR] Updating template "test_in/file" -> "test_out/file" but target contents were changed. Skipping.
    Difference between expected and actual:
    //or
    Refusing to make the following change:
// diff here

That makes sense to me. I'll update the behavior

[ditsuke]

@SuperCuber

I've updated it to target -> source. Here's what it looks like now:

❯ ./dotter -v     
[ERROR] Updating template ".gitconfig" -> "/home/dt/.gitconfig" but target contents were changed. Skipping
[ INFO] Refusing because of the following changes in source: 
 19 | 19 | [gpg]
 20 |    |      program = /usr/bin/gpg
    | 20 |      program = /usr/bin/gpg2
[ERROR] Some files were skipped. To ignore errors and overwrite unexpected target files, use the --force flag.

[SuperCuber]

Thanks for the contribution!

[ditsuke]

Thanks for accepting!