Fixed implementation of RichTextLabel remove_line(), which fixed issues in EditorLog.

[EricEzaM]

There were some issues in RichTextLabel remove_line() method, where items were not correctly removed, and line decremending for items in later lines was not correctly done.

This also fixed several headaches with EditorLog, which relied on the remove_line() method for collapsing of duplicate messages.

I added some comments which should help clarify some of the logic for the next person to look at this code.

Fixes #49030

See #49030 for the code which I used for the below samples. Essentially the spacebar just calls remove_line(get_line_count() - 1), which should remove the last line of the rich text label. I also tested the update with code which removes lines from the middle of a set of lines and it worked as expected.

Note the "Before" was even more broken because an update() was not triggered on remove_line() - for the below "Before" showcase I added a manual call to update() in the GDScript code.

BEFORE

RTL_BROKEN_example.mp4

AFTER

RTL_FIXED_example.mp4

Editor Log AFTER

RTL_FIXED_editorlog.mp4

CC @KoBeWi I hope you can stop submitting reports about EditorLog now... 😂

[KoBeWi]

CC @KoBeWi I hope you can stop submitting reports about EditorLog now... 😂

Haha, you wish XD

Printing is still broken, but only after starting.

func _process(delta):
	print("test")

Clearing the text fixes it permanently.

[EricEzaM]

Uhhh... Progress...? 😅

[EricEzaM]

More issues with RichTextLabel... see #45128 (comment)

get_line_count() was not counting the number of lines internally in RichTextLabel, but all rendered lines... So if there was long enough text to go over multiple lines, it would report more lines than was is current_frame->lines.size(), which is what remove_line checks against when it removes lines. I have added a new separate commit to this PR to add an optional parameter to get_line_count() which allows optionally including wrapped lines as multiple lines or as one line.

cc @KoBeWi @bruvzg

See the below video, I highlight the lines which wrap. These increased the value of get_line_count() by 2, so when I called remove_line(get_line_count() - 2), it returned early since the index was out of bounds of lines.size()

RTL_LOG_FIXED.mp4

[EricEzaM]

Ok, turns out what I was after was get_paragraph_count() which is what get_line_count() used to be.

Updated

[KoBeWi]

Looks like the bug is fixed... for now.

[akien-mga]

Thanks!

[EricEzaM]

@KoBeWi have some confidence 😭 😛