feat: add only diff run flag

[rusinikita]

Proposed changes

Running mutations only for changes. A new flag diff runs git diff with reference and skip mutants outside of changes.

Killed: 16, Lived: 0, Not covered: 1
Timed out: 0, Not viable: 0, Skipped: 168
Test efficacy: 100.00%
Mutator coverage: 94.12%

Look at docs change for details.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• Lint and unit tests pass locally with my changes (make all)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

Further comments

[k3rn31]

Hello and thanks for the PR. We'll do a review ASAP. In the mean time can you pleas check the failing CI checks?

[rusinikita]

Hi! Yes, of course. I just want to get approve of solution design. Is it good for you?

[rusinikita]

Fixed. But I need advice about engine.New has 5 arguments (exceeds 4 allowed) codeclimate issue.

• I can pass Diff with Option
• I can create params struct
• Or something else

[rusinikita]

@k3rn31 Hi! I'm thinking about adding this to my work projects.

How much time will a review take?

If it's not long I'll wait for a merge.

[k3rn31]

Hi! we're doing the review today, it looks promising (except for one Codeclimate linting error). I believe I'll merge soon on develop, but I'm not sure when we'll make a new release. This is a good change we'll make an extra release earlier to let this feature available right away.

[rusinikita]

Ok, thanks!

It looks promising (except for one Codeclimate linting error)

About that. I want be in sync with your vision and wanna know a way that you prefer:

I need advice about engine.New has 5 arguments (exceeds 4 allowed) codeclimate issue.

• I can pass Diff with Option
• I can create params struct
• Or something else

[k3rn31]

I think the struct param is better, since we don't use it as a library and the option doesn't make sense to me.

[rusinikita]

I combined a coverage and diff into CodeData. So it can be extended in future for solving #167

Let me know if you want to rename it or squash/rename some commits.

[codecov]

Codecov Report

Attention: 17 lines in your changes are missing coverage. Please review.

Comparison is base (b62af32) 88.57% compared to head (e8cedb3) 88.02%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
cmd/unleash.go	9.09%	10 Missing ⚠️
internal/engine/engine.go	70.00%	2 Missing and 1 partial ⚠️
internal/diff/parse.go	90.00%	2 Missing ⚠️
internal/mutator/mutator.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #215      +/-   ##
==========================================
- Coverage   88.57%   88.02%   -0.56%     
==========================================
  Files          18       20       +2     
  Lines        1322     1394      +72     
==========================================
+ Hits         1171     1227      +56     
- Misses        126      141      +15     
- Partials       25       26       +1     

Flag	Coverage Δ
unittests	88.02% <79.26%> (-0.56%)	⬇️

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[k3rn31]

I think your implementation is sound.
I would have taken a slightly different approach: instead of marking a mutator as "skipped", you could mark it as runnable or not (if the diff flag is active) in the same spot where it checks if it has coverage. This way no changes would have been necessary in the executor.