fix: toggle tabline when tab added w/o new buffer

[baodrate]

Currently, when a tab is created without a new buffer being added (e.g. <C-W>s<C-W>T), tabline visibility is not toggled. Fix this edge case so that the tabline is displayed when there are either >1 buffers or the tab indicators are enabled and there are >1 tabs.

[akinsho]

Tab indicators should be the thing that triggers tabline visibility the tab indicators are about whether or not the indicator for buffer users is visible or not. I don't think I understand this problem entirely since AFAICT, the situation you describe of using this command should still cause the tab count to be > 1 and so that should be enough to trigger visibility

[baodrate]

the situation you describe of using this command should still cause the tab count to be > 1 and so that should be enough to trigger visibility

Note that the condition is currently config:is_tabline() and utils.get_tab_count() or utils.get_buf_count():

bufferline.nvim/lua/bufferline.lua

Lines 90 to 92 in 0dfc19b

	local function toggle_bufferline()
	if not config.options.auto_toggle_bufferline then return end
	local item_count = config:is_tabline() and utils.get_tab_count() or utils.get_buf_count()

When the mode is not tabs, toggle_bufferline only considers the number of buffers. So the user opens multiple tabs but with a single buffer, toggle_bufferline will never show the tabline, and even though there might be multiple tab indicators visible, the entire tabline is still hidden.

the tab indicators are about whether or not the indicator for buffer users is visible or not

Yes. I'm checking for this condition because if there are multiple tabs but a single buffer, we only need to display the bufferline if the user enables the tab indicators. This is to avoid the confusing situation of bufferline displaying when there is a single buffer and tab indicators are hidden.

[akinsho]

Hmm tbh I'm not sure it's clear that it should behave this way. I think the tabline should only show if there are multiple buffers in buffer mode, doesn't necessarily seem right to me that it'll respond to tabs at all since that isn't the consideration in that mode. It will also certainly result in a change that some people will definitely not like and raise issues about probably

[baodrate]

Okay. My reasoning is that if the user both enabling tab indicators and explicitly opening multiple tabs is a good indication that they'd like to see those tabs. But I respect your judgement. I have this function monkey-patched in my config so I can live with it.

[akinsho]

Thanks @baodrate for the contribution, I'll revisit this if a bunch of other people start clamouring for it but in the short term I'd rather avoid changes that could stir up issues or conversation