## Problem
Repeatedly toggling `=` in fugitive left green gutter
(`number_hl_group`)
extmarks on lines between sections. When fugitive collapses a diff
section,
Neovim compresses extmarks from deleted lines onto the next surviving
line
(the `M ...` file entry). Two issues prevented cleanup:
1. `carry_forward_highlighted` returned `{}` (truthy in Lua) when zero
hunks
matched, so `pending_clear` stayed `false` and the compressed extmarks
were never cleared.
2. The `nvim_buf_clear_namespace` call in `on_buf`'s `pending_clear`
path was
removed in 2feb8a8, so even when `pending_clear` was `true` the extmarks
survived.
## Solution
Return `nil` from `carry_forward_highlighted` when no hunks were carried
forward (`next(highlighted) == nil`), so `pending_clear` is correctly
set to
`true`. Restore `nvim_buf_clear_namespace` in `on_buf`'s `pending_clear`
block. Add `process_pending_clear` test helper and spec coverage.
749a21ae3c