SplitPane using `top_level = true` leaves behind ghost space

[amanjitsk]

What Operating System(s) are you seeing this problem on?

Linux X11

Which Wayland compositor or X11 Window manager(s) are you using?

bspwm w/ picom

WezTerm version

wezterm 20240208-085947-f671a9ab

Did you try the latest nightly build to see if the issue is better (or worse!) than your current version?

Yes, and I updated the version box above to show the version of the nightly that I tried

Describe the bug

When splitting across the full width (/length) using SplitPane({ top_level = true }), it causes the next call to SplitPane to fail, and even with the pane closed (this is the same bug reported in #2579), it seems that the space is still occupied by the now closed pane (created using top_level = true).

To Reproduce

1. Start with a single pane in a tab

|       |
    1
|       |

2. Create a vertical split (split it bottom)

|   1   |
---------
|   2   |

3. Split Pane 2 horizontally to the right using the full height i.e. `SplitPane({ top_level = true, direction = "Right" })

| 1 |   |
----| 3
| 2 |   |

4. Trying to split Pane 3 does not work anymore. Furthermore, even if Pane 3 is closed, splitting Pane 1 or 2 does not work either (see #2579)
5. Closing Pane 3 and 2 now, and repeating Step 2. now results in the following layout (unexpected)

| 1 |   |
----|  
| 2 |   |

with the space previously occupied by Pane 3 still empty.

Configuration

no config

Expected Behavior

Step 5. should result in a layout like Step 2., but the space previously occupied by a full-width (/height) pane remains occupied.

Logs

Debug Overlay
wezterm version: 20240208-085947-f671a9ab x86_64-unknown-linux-gnu
Window Environment: X11 bspwm
Lua Version: Lua 5.4
OpenGL: Mesa Intel(R) HD Graphics 520 (SKL GT2) 4.6 (Compatibility Profile) Mesa 23.0.4-0ubuntu1~22.04.1
Enter lua statements or expressions and hit Enter.
Press ESC or CTRL-D to exit
14:20:34.542 ERROR wezterm_gui::spawn > Failed to spawn: split_pane: No space for split!
14:20:35.819 ERROR mux::tab > No space for split!!! SplitDirectionAndSize {
    direction: Vertical,
    first: TerminalSize {
        rows: 11,
        cols: 210,
        pixel_width: 1890,
        pixel_height: 220,
        dpi: 96,
    },
    second: TerminalSize {
        rows: 12,
        cols: 210,
        pixel_width: 1890,
        pixel_height: 240,
        dpi: 96,
    },
} height=24 width=210 top_of_second=12 left_of_second=0 tab_size=TerminalSize { rows: 48, cols: 104, pixel_width: 936, pixel_height: 960, dpi: 96 }
14:20:35.819 ERROR wezterm_gui::spawn > Failed to spawn: split_pane: No space for split!
14:20:37.721 ERROR mux::tab > No space for split!!! SplitDirectionAndSize {
    direction: Horizontal,
    first: TerminalSize {
        rows: 23,
        cols: 104,
        pixel_width: 936,
        pixel_height: 460,
        dpi: 96,
    },
    second: TerminalSize {
        rows: 23,
        cols: 105,
        pixel_width: 945,
        pixel_height: 460,
        dpi: 96,
    },
} height=23 width=210 top_of_second=0 left_of_second=105 tab_size=TerminalSize { rows: 48, cols: 104, pixel_width: 936, pixel_height: 960, dpi: 96 }
14:20:37.722 ERROR wezterm_gui::spawn > Failed to spawn: split_pane: No space for split!
14:27:41.255 ERROR wezterm_mux_server_impl::local > writing pdu data buffer: Broken pipe (os error 32)
14:36:43.949 ERROR wezterm_mux_server_impl::local > writing pdu data buffer: Broken pipe (os error 32)
14:37:08.103 ERROR mux::tab > No space for split!!! SplitDirectionAndSize {
    direction: Horizontal,
    first: TerminalSize {
        rows: 25,
        cols: 104,
        pixel_width: 936,
        pixel_height: 500,
        dpi: 96,
    },
    second: TerminalSize {
        rows: 25,
        cols: 105,
        pixel_width: 945,
        pixel_height: 500,
        dpi: 96,
    },
} height=25 width=210 top_of_second=0 left_of_second=105 tab_size=TerminalSize { rows: 50, cols: 104, pixel_width: 936, pixel_height: 1000, dpi: 96 }
14:37:08.104 ERROR wezterm_gui::spawn > Failed to spawn: split_pane: No space for split!
>

Anything else?

No response