Split Bug at Start of Line

[joegm]

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Summary

When Split is used with a pattern that matches the start of a line, a selection is placed on the match even when there aren't any characters before it:

https://asciinema.org/a/NDCiZr7kfsMiUEuI88K37vybT

Reproduction Steps

I tried this:

1. hx
2. i| | | |(esc)S\|(ret)

I expected this to happen: The spaces in between and the newline would be selected

Instead, this happened: There was an additional selection at the start of the line.

Helix log

N/A

Platform

Linux

Terminal Emulator

Alacritty

Helix Version

22.08.1-61-gb191ecf8

[the-mikedavis]

This looks like https://github.com/helix-editor/helix/issues/3544. The same fix from https://github.com/helix-editor/helix/pull/3598/files can probably be applied to split_on_matches

[palango]

I think there are some edge cases that need to be decided. For example, on the input |a|b|c|, and a split on | what would be the expected outcome: three or four selections?

For me it feels more natural to have three, but have the special case of having the first selection remaining if there is no match. I implemented this in https://github.com/palango/helix/commit/17d1cd3d7be4677f635632d68af2c4612d6e4d31#diff-f218cebd639a867087e2a7abc84160d45888ad5bcff4ab10fcf7217cb16586e9R1303 , however the code isn't optimized yet.