Inconsistent behavior around vim.api.nvim_tabpage_set_var and vim.api.nvim_tabpage_get_var

[synic]

Problem

This is kind of hard to explain, but setting variables using vim.api.nvim_tabpage_set_var doesn't always bind them to the tab itself, rather, it binds them to the tab page number, and vim.api.nvim_tabpage_get_var doesn't always return the variable that's bound to the tab, sometimes it returns a variable that was bound to the tab page number with vim.api.nvim_tabpage_set_var.

The result is that the variable isn't really bound in a predictable way, and if you move or otherwise rearrange tabs, the variables will no longer be bound to the correct tab.

Steps to reproduce

1. Type nvim --clean
2. Open 3 tabs by typing :tabnew and enter three times.
3. Make sure you are on the last tab by typing 3gt.
4. Type :lua vim.api.nvim_tabpage_set_var(vim.fn.tabpagenr(), "foo", "foo")
5. Type :echo t:foo, observe that it echos foo
6. Type :lua print(vim.api.nvim_tabpage_get_var(vim.fn.tabpagenr(), "foo")), observe that it prints foo
7. Type :tabmove 0 to move this tab to the first tab in the list.
8. Type :echo t:foo, observe that it echos foo
9. Type :lua print(vim.api.nvim_tabpage_get_var(vim.fn.tabpagenr(), "foo")), it is an error!
10. Type 3gt to go to the last tab in the list
11. Type :echo t:foo, it is an error (expected)
12. Type :lua print(vim.api.nvim_tabpage_get_var(vim.fn.tabpagenr(), "foo")), it prints foo!

It's like vim.api.nvim_tabpage_get_var and vim.api.nvim_tabpage_set_var use an intermediary storage place and it is NOT properly synced when tabs are rearranged.

Expected behavior

The variable should be bound to the tab, not the tab page number, and vim.api.nvim_tabpage_get_var and vim.api.nvim_tabpage_set_var should synchronize with tab rearrangements correctly.

Neovim version (nvim -v)

v0.10.0-dev-2173+g6cbfe4545-Homebrew

Vim (not Nvim) behaves the same?

This is Neovim only

Operating system/version

MacOS 14.3.1

Terminal name/version

Iterm 3.4.23

$TERM environment variable

xterm-256color

Installation

Homebrew

[zeertzjq]

nvim_tabpage_set_var and nvim_tabpage_get_var do not take tabpage numbers as argument. They take tabpage handles. You need to use nvim_list_tabpages to map tabpage numbers to tabpage handles.

[synic]

ah, thank you!