feat: add TabPanel

[rbtnn]

hi, Vim developers .

This PR is to add TabPanel feature. TabPanel is a vertical sidebar that displays tab page labels along the side of the window. It looks like this:

This works on Huge build only.

[h-east]

Would you like to rebase?

[rbtnn]

Would you like to rebase?

Okay, I have rebased.

[Copilot]

Pull Request Overview

This PR adds a new TabSideBar feature by adjusting screen coordinate calculations to account for the sidebar's width, as well as refreshing the UI appropriately when certain commands modify buffers. Key changes include modifying the drawing routines (e.g. in ex_docmd.c, edit.c, and drawscreen.c) to add a TSB_LCOL offset, updating command execution functions to trigger tab sidebar redraws, and adding a new evaluation flag for "tabsidebar" in evalfunc.c.

Reviewed Changes

Copilot reviewed 70 out of 82 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/ex_docmd.c	Adjusted windgoto() to add TSB_LCOL offset for proper positioning.
src/ex_cmds.c	Triggered redraw_tabsidebar in response to file rename/write events.
src/evalfunc.c	Added a "tabsidebar" feature flag with conditional evaluation.
src/edit.c	Adjusted screen_putchar() calls to include TSB_LCOL offset.
src/drawscreen.c	Updated several redraw and screen drawing calls to account for the new sidebar.
src/drawline.c	Propagated the sidebar offset into the drawline functions.
src/clipboard.c	Updated rectangle drawing with TSB_LCOL offset.
src/change.c	Ensured tab sidebar is redrawn when buffer content changes.

Files not reviewed (12)

• Filelist: Language not supported
• runtime/doc/options.txt: Language not supported
• runtime/doc/syntax.txt: Language not supported
• runtime/doc/tabpage.txt: Language not supported
• runtime/doc/tags: Language not supported
• runtime/doc/various.txt: Language not supported
• runtime/syntax/vim.vim: Language not supported
• src/Make_ami.mak: Language not supported
• src/Make_cyg_ming.mak: Language not supported
• src/Make_mvc.mak: Language not supported
• src/Make_vms.mms: Language not supported
• src/Makefile: Language not supported

[chrisbra]

Thanks this looks useful. I left a few comments.
Can you please also update $VIMRUNTIME/optwin.vim?

[habamax]

I wonder how it would look like if the filename is very long.

As an extreme example, would it take half(or more) of the screen if the buffer/file name is aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.txt?

Does it show the shorten path of the file/buffer (would there be the way to set it up?):

[zeertzjq]

From a rough look at the code change I think there is some inconsistency:

• win_screenpos() and screenpos() start counting column numbers from the right edge of the tabsidebar
• But getmousepos() starts counting column numbers from the left edge of the screen

[habamax]

I wonder how it would look like if the filename is very long.

Aha, I can see option to wrap it.

[thinca]

I helped a little bit with the development of the tabsidebar feature.
I replied to the best of my knowledge.

[h-east]

Some TbbSideBar related options would be better grouped under 'tabsidebaropt', like 'diffopt'.

Example:

set tabsidebaropt=align:left,columns:0,wrap

[jmdevin]

I know it sounds like bikeshedding, but I think this feature is better named as 'TabPanel' than 'TabSideBar'. The option for it could be tabpanelopts. I elaborated a bit in another comment: link.

[rbtnn]

I know it sounds like bikeshedding, but I think this feature is better named as 'TabPanel' than 'TabSideBar'. The option for it could be tabpanelopts. I elaborated a bit in another comment: link.

Okay, I will rename to TabPanel from TabSideBar.

[bfrg]

Why does this have to be hard coded into vim? Why not a vimscript plugin?

[chrisbra]

thanks all!

[rbtnn]

Thank you for the code review. I look forward to working with you further.

[zeertzjq]

From a rough look at the code change I think there is some inconsistency:

* `win_screenpos()` and `screenpos()` start counting column numbers from the right edge of the tabsidebar

* But `getmousepos()` starts counting column numbers from the left edge of the screen

This problem still isn't addressed.

Example: :set showtabpanel=2 and click on the top-left corner of the current window. getmousepos() returns

{'screencol': 21, 'coladd': 20, 'screenrow': 1, 'column': 1, 'winrow': 1, 'line': 1, 'wincol': 1, 'winid': 1000}

but screenpos(0, 1, 1) returns

{'col': 1, 'row': 1, 'endcol': 1, 'curscol': 1}

as you can see, col from screenpos() is inconsistent with screencol from getmousepos().

Note that the current behavior is inconsistent with 'tabline', where both screenpos() and getmousepos() start counting row numbers from the top of the screen. If you :set showtabline=2 and click on the top-left cursor of the current window, getmousepose() returns

{'screencol': 1, 'coladd': 0, 'screenrow': 2, 'column': 1, 'winrow': 1, 'line': 1, 'wincol': 1, 'winid': 1000}

while screenpos(0, 1, 1) returns

{'col': 1, 'row': 2, 'endcol': 1, 'curscol': 1}

so row from screenpos() is consistent with screenrow from getmousepos().

[habamax]

This doesn't look right:

with set showtabpanel=1

without it:

Note to vim/colorschemes -- tabpanel probably needs different background.

[habamax]

There is an issue with :tabonly, let me create a separate one.

[h-east]

@rbtnn
I think that both of my suggestions 1 and 2 below should be addressed.
#17263 (comment)

You are using too few words, so I cannot understand your thoughts. Could you please not only show the code changes but also articulate your thoughts in writing?

[h-east]

@Shane-XB-Qian

not sure if you (anyone) noticed typing became flaky when tabpanel opened, seems 'redraw' too often?

Could you please provide the settings (.vimrc) from that time in the simplest configuration, if possible?

[h-east]

I couldn't reproduce it. (ms-win: gvim.exe, vim.exe, Ubuntu 22.04: CLI Vim) (Latest version of Vim)
Does it occur without any input?
Could you please try the following at least?

$ vim --clean +"set showtabpanel=2 tabpanelopt=vert" +tabnew

[h-east]

expanding tabpanelopt cli compl items seems wrong

1. there is no wrap option in its doc which looks should be removed compl items
2. seems option vert no value can be inputted, so it should be just vert vs not vert:

Both of these are bugs in the tabpanelopt completion feature. What's written in the documentation is correct.
Thanks for letting me know.

[jmdevin]

@chrisbra I think it would have been good to @ the people in this thread again requesting a review before committing this pr. When I made my comment pointing out some bugs (link), I just reported the first couple I found; I didn't do a fuller deep dive into the feature because I assumed that someone would comment saying it was fixed, please test it again. Looking at a few of the issues reported since this pr was accepted, I'm pretty sure we would have discovered at least a few, if not most, of them beforehand. Issue #17322 is basically the same as what I showed in my initial comment, so I think I would have found it.

I know vim doesn't use a separate development/stable branch, so if this is just how development is done I understand; I just want to make it clear I would've been happy to do some additional testing and bug reporting before this got accepted.

[chrisbra]

Thanks for the feedback. I'll keep it in mind for the future.

[benknoble]

Hm. I suppose it's too late to rename g:actual_curtabpage? There's some redundancy there that feels awkward.

[h-east]

g:actual_curbuf and g:actual_curwin existed before this feature was added, so I think it was changed to match those.
Perhaps you want to change it to g:actual_curtab?
Hmm, tab has various interpretations, so I think they went with tabpage.
In fact, tab does not appear alone in :h tabpage.txt (except for :tab as a command).

[chrisbra]

I would also think curtabpage is fine. It's a bit verbose but clear on what is meant.

[benknoble]

g:actual_curbuf and g:actual_curwin existed before this feature was added, so I think it was changed to match those.

Ah, I was unaware of that. Consistency is probably best, even if I would drop the "actual" here (it makes it seem like there's a g:curbuf/win/tabpage that's not the real one, as in the "final actual real final version" kind of naming ;).