o/O interact badly with multiple cursors

[loewenheim]

Summary

Having multiple cursors on different lines and pressing o/O to insert a line beneath/above each of them behaves unexpectedly, see below for details. I suspect there is a calculation for how many characters each cursor needs to be moved forward that gets messed up by the lines being inserted.

Reproduction Steps

o case

1. Have a file with two lines, say

foo
bar

2. Have a cursor on of each line
3. Press o

Expected

foo
|
bar
|

(| is a cursor)

Actual

foo
|
bar|

The second newline is inserted, but the cursor isn't moved to it, it's moved to the end of the current line. It doesn't matter which cursor is the primary, only the order in the file matters. The result for 3 lines is even weirder:

foo
bar
baz

becomes

foo
|
bar|

ba|z

O case:

Setup as above, but press O

Expected

|
foo
|
bar

Actual

|
foo|

bar

Helix log

Platform

macOS 15.0.1

Terminal Emulator

kitty 0.34.1

Installation Method

flake

Helix Version

helix 25.01 (e01775a)

[TornaxO7]

Duplicate of #12448. Fix is already merged in master.

[loewenheim]

Thanks for the quick action. I tried looking for a duplicate but missed it 🙇

[TornaxO7]

Thanks for the quick action. I tried looking for a duplicate but missed it 🙇

No problem. Happens