fix(operators): correctly handle newlines at start of textobject

[TheLeoP]

• I have read CONTRIBUTING.md
• I have read CODE_OF_CONDUCT.md

Partially fixes #2247

[echasnovski]

If it is a change in do_between_marks, then I think it is reasonable to also add tests for all operators that use it. Namely, "multiply" and "exchange".

Also, I am a bit hesitant to yet merge this as it doesn't address both problems of #2247.

[TheLeoP]

If it is a change in do_between_marks, then I think it is reasonable to also add tests for all operators that use it. Namely, "multiply" and "exchange".

On it.

Also, I am a bit hesitant to yet merge this as it doesn't address both problems of #2247.

Fair. I'll try to take a look at what may be causing the issue with the trailing newline tomorrow

[TheLeoP]

I changed the commit message to include newlines at the end of textobject because I added a test for a different edge case on MiniOperators.replace that happened only on visual mode and only when replacing a region with a trailing newline. But, the operator still duplicates the trailing newline (it can't delete it because, as explained in #2247 (comment) , custom operators can't see trailing newlines).

We would be accepting that this is a current limitation of Neovim and the behavior is expected.

[echasnovski]

Could you please move cache-set-unset of 'virtualedit' at least inside H.exchange_do or explore if only moving it inside H.replace_do is enough . Preferably closer to commands when they are actually needed (i.e. not at the top and bottom).

Also, please add the same one-line comment above each 'virtualedit' caching describing why this is needed.

For tests, it looks like the behavior is Visual mode specific. So could you please move them after 'works in Visual mode' cases for each operator and be more general like 'works with newline in region'. For trailing newlines in exchange and multiply having a comment about why it doesn't work (like Doesn't work due to Neovim limitations\nSee https://github.com/neovim/neovim/issues/37664).

[echasnovski]

I currently have time to finish nit-picking parts myself. Hope to merge into main soon-ish.

[echasnovski]

The first version of this (with only do_between_marks) should now be part of latest main.

After looking more closely, having all "cache-set-unset" separate didn't gain much. The only case is for "replace" to act less wrong on trailing newline. The problem is that the resulting behavior is still wrong (replacing a region with itself should have produced the same text, not add another line).

So as the first version is much simpler and to the point, let's go with that one.

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Thanks for all the deep research and PR to make 'mini.operators' better in this very narrow use case :)