feat: If core.autocrlf is enabled, replace CRLF with LF when adding to index

[rdbisme]

This is to mimic the same behaviour the standard git command has.

Apart for the blackification, relevant lines are the definition of the class _FileStore, the addition of the method _autocrlf, and the adaptations in add() to use the _FileStore contextmanager.

The logic here is to replace \r\n with \n when adding to the index, then reset the local file to the original content.

[rdbisme]

It would be much easier to contribute if using black for style autolinting

[Byron]

May I ask to adjust the commits to not do code formatting? I am happy to run it through black to unify the style and if it doesn't make it (too much) worse, but that should be a separate step.

All these changes are like noise to the signal making a review harder than it has to be. Thanks.

[rdbisme]

Thanks for taking the time of applying black. I rebased everything on top of the latest commit and now the changes should more clear :)

[Byron]

Thanks for the contribution and the intention to fix a shortcoming.
However, I don't feel comfortable to add 'a very special filter' that will inadvertently affect current users that build upon the existing, very limited behaviour. It has a huge potential to cause breakage and thus I see no way to add it in its current form.

GitPython has been done very much in that fashion - implement something to mimic the actual behaviour of git - which has caused an incredible amount of problems and surprises down the road. It's just not a paradigm that should be continued.

I am sorry, but I see no way forward for this PR, and thank you for your understanding.

[rdbisme]

Thanks for the contribution and the intention to fix a shortcoming. However, I don't feel comfortable to add 'a very special filter' that will inadvertently affect current users that build upon the existing, very limited behaviour. It has a huge potential to cause breakage and thus I see no way to add it in its current form.

GitPython has been done very much in that fashion - implement something to mimic the actual behaviour of git - which has caused an incredible amount of problems and surprises down the road. It's just not a paradigm that should be continued.

I am sorry, but I see no way forward for this PR, and thank you for your understanding.

Ok, no problem. Thanks for reviewing! :)