Fixes on Jupyter notebooks cause panics when fix replaces/deletes multiple cells

[beskep]

• command: ruff check .\src\test.ipynb --fix --diff (No panic when --isolated included)

• ruff version: 0.7.4

• pyproject.toml

  
  [project]
  requires-python = ">=3.13"
  dependencies = ["ruff>=0.7.4"]

[tool.ruff] preview = true

[tool.ruff.lint] select = ["W"]

- ipynb file: [test.ipynb.zip](https://github.com/user-attachments/files/17807695/test.ipynb.zip)

[dylwil3]

Thanks so much for this!

This can be reproduced with a notebook that just consists of three empty cells. We are somehow counting empty cells as newlines and then erroring when we try to "delete" them.

[dylwil3]

Actually this bug has a wider blast radius.

If you make a notebook with three cells like this:

a = [1]
a.append(2)
# new cell
a.append(3)
# new cell
a.append(4)

and apply the unsafe fix for FURB118 you also get a panic.

[dhruvmanila]

I'm guessing that cell deletion is creating a problem when update_cell_offsets and update_cell_contents are being called.