From 7a552f415c48aed33bf7eaa3c50e78504d417913 Mon Sep 17 00:00:00 2001
From: Christian Brabandt <cb@256bit.org>
Date: Thu, 5 Dec 2024 06:49:09 +0100
Subject: [PATCH] highlighter: remove stale separator entries on buffer unload

fixes: #2701

Co-authored-by: Mina Nagy Zaki <mnzaki@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
---
 autoload/airline/highlighter.vim | 16 +++++++++++++++-
 plugin/airline.vim               | 10 ++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/autoload/airline/highlighter.vim b/autoload/airline/highlighter.vim
index a9151009..2efca60d 100644
--- a/autoload/airline/highlighter.vim
+++ b/autoload/airline/highlighter.vim
@@ -186,6 +186,13 @@ if !exists(":def") || !airline#util#has_vim9_script()
     call <sid>exec_separator({}, a:from, a:to, a:inverse, '')
   endfunction
 
+  function! airline#highlighter#remove_separators_for_bufnr(bufnr) abort
+    " remove all separators, that have the buffer number in their name,
+    " but do not be too greedy!
+    let pat = 'c' . a:bufnr . '\(\D\|$\)'
+    call filter(s:separators, 'v:key !~# pat')
+  endfunction
+
   function! s:exec_separator(dict, from, to, inverse, suffix) abort
     if pumvisible()
       return
@@ -529,6 +536,13 @@ else
     s:exec_separator({}, from, to, inverse, '')
   enddef
 
+  def airline#highlighter#remove_separators_for_bufnr(bufnr: string): void
+    # remove all separators, that have the bufnr in its name, make sure we 
+    # have a full match here
+    const pat = $'c{bufnr}\(\D\|$\)'
+    filter(s:separators, (k, v) => k !~# pat)
+  enddef
+
   def s:exec_separator(dict: dict<any>, from_arg: string, to_arg: string, inverse: bool, suffix: string): void
     if pumvisible()
       return
@@ -681,5 +695,5 @@ else
         endfor
       endif
     endfor
-	enddef
+  enddef
 endif
diff --git a/plugin/airline.vim b/plugin/airline.vim
index 17374b3f..7869be05 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -48,6 +48,7 @@ function! s:init()
 endfunction
 
 let s:active_winnr = -1
+
 function! s:on_window_changed(event)
   " don't trigger for Vim popup windows
   if &buftype is# 'popup'
@@ -67,11 +68,20 @@ function! s:on_window_changed(event)
         \ && &ft !~? 'gitcommit'
     " fugitive is special, it changes names and filetypes several times,
     " make sure the caching does not get into its way
+    if a:event ==# 'BufUnload'
+      " in the BufUnload event, make sure the cacheing does not prevent
+      " removing stale entries
+      call airline#highlighter#remove_separators_for_bufnr(expand('<abuf>'))
+    endif
     return
   endif
   let g:airline_last_window_changed = l:key
   call s:init()
   call airline#update_statusline()
+
+  if a:event ==# 'BufUnload'
+    call airline#highlighter#remove_separators_for_bufnr(expand('<abuf>'))
+  endif
 endfunction
 
 function! s:on_focus_gained()