RichTextLabel clear() fails

[Koyper]

Godot version

3.4 stable

System information

OSX

Issue description

When creating multiple instances containing a RichTextLabel in a for statement, clear() at _ready() and _enter_tree() fails to clear the placeholder text in bbcode_text

This worked in 3.3 stable.

Steps to reproduce

Create a scene with a RTL and placeholder bb code in bbcode_text that calls clear() at _ready();

In a parent scene, add multiple instances of the above scene to a grid container;

You should see the placeholder bbcode_text instead of empty bbcode_text.

Minimal reproduction project

No response

[Calinou]

@Koyper Please upload a minimal reproduction project to make this easier to troubleshoot.

[Koyper]

RichTextLabel_clear_bug2.zip

Running in 3.3 stable returns a cleared panel - running in 3.4 stable returns tiles of placeholder text.

[Koyper]

Simply removing the theme resource setting in the parent scene causes it to work correctly.

[Koyper]

Additionally, by initial steps will not reproduce the bug - I had to work to strip it down to the minimal to find out what would reproduce it...

[Koyper]

...my initial steps...

[timothyqiu]

This is an regression since 3.3.3. clear() here succeeded, but the tag stack is built again during the THEME_CHANGED notification.

clear() never set bbcode_text to an empty string (but stated to in the doc), and #49174 introduces the behavior of rebuilding the tag stack with bbcode_text when theme changed.

So, should clear() set bbcode_text to empty?

[akien-mga]

So, should clear() set bbcode_text to empty?

I guess yeah.

[timothyqiu]

After a bit more inspection, it seems RichTextLabel don't expect clear() to touch bbcode_text. e.g.

godot/scene/gui/rich_text_label.cpp

Lines 2590 to 2598 in 8cedf91

	void RichTextLabel::set_bbcode(const String &p_bbcode) {
	bbcode = p_bbcode;
	if (is_inside_tree() && use_bbcode) {
	parse_bbcode(p_bbcode);
	} else { // raw text
	clear();
	add_text(p_bbcode);
	}
	}

Since push_*(), pop_*() methods only touch the tag stack, I think it makes sense for clear() to also leave bbcode_text as is and it's the documentation that's wrong.

[Koyper]

In that case I'm wondering why clear() was exposed in the first place? Anything assigned to the bbcode text will call clear() because parse_bbcode also calls clear(). Is there a case where you would want to clear the tag stack but leave behind the bbcode text?

[timothyqiu]

RichTextLabel is based on a tag stack, so basic stack operations like push_*(), pop_*(), and clear() are available. BBCode text is an easier way to modify the tag stack, but not in reverse. i.e. Setting BBCode updates the tag stack, but changing the tag stack won't affect BBCode. There was a discussion about this somewhere, but I failed to find it now.

The editor help and editor output panel both modify the RichTextLabel with these functions directly instead of BBCode.

[akien-mga]

CC @bruvzg. Sounds like this just needs a documentation clarification?