Context

Wayland's write_to_clipboard and write_to_primary exclusively use SerialKind::KeyPress as the serial. When Wayland users try to copy using the mouse without having pressed a key on the keyboard, state.serial_tracker.get(SerialKind::KeyPress) could return 0, causing users to experience failed writes to the clipboard or primary with no visibility of what failed or why.

I have added a latest_of(...) helper in crates/gpui_linux/src/linux/wayland/serial.rs which returns the most recent tracked serial of the SerialKinds provided. In crates/gpui_linux/src/linux/wayland/client.rs, I call this new helper so serial is assigned the latest tracked serial of kind KeyPress or MousePress.

I, personally, only reproduced the bug on KDE Plasma (Wayland). All the reports with confirmed desktop environments have been KDE Plasma, though it may also affect other desktop environments. I have tested this fix on KDE Plasma and Niri.

What I have manually tested

• Copy with mouse, paste with mouse (no prior KeyPress)
• Copy with mouse, paste with keyboard (no prior KeyPress)
• Select with mouse, paste with middle mouse button (no prior KeyPress)
• Copy with keyboard, paste with keyboard
• Copy with keyboard, paste with mouse

Still need help

• Is this the preferred approach?
• The first time I tested, the 3rd or 4th paste with the mouse pasted a stale clipboard entry (top two lines of buffer in video), but I have been unable to reproduce it.

How to Review

May need to be on KDE Plasma (see note in context section)

• cargo run
• Double click to select text (must select using the mouse)
• Middle mouse click to paste primary using write_to_primary and observe content is pasted correctly
• Click and drag to select different text
• Right click on text
• Select "copy" (must use mouse since keyboard keypresses sometimes avoided the bug)
• Right click and select "paste"
• Observe pasted content is correct

Self-Review Checklist

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content is consistent with the UI/UX checklist
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Release Notes:

• Fix copy for some Wayland users