From 07df7903af79af6701a5fa64d2680d8be7ed290d Mon Sep 17 00:00:00 2001
From: leafOfTree <node_github@163.com>
Date: Wed, 21 Oct 2026 12:12:56 +0000
Subject: [PATCH] Undo ftplugin and indent settings when filetype changes

Set b:undo_ftplugin for matchpairs, matchit variables, b:syng_str and
the foldexpr settings, and b:undo_indent for indent settings, instead of
relying on whichever indent file was loaded last.
---
 ftplugin/vue.vim      |  5 +++++
 ftplugin/vue/fold.vim |  2 ++
 indent/vue.vim        |  1 +
 test/cases/undo.vim   | 17 +++++++++++++++++
 test/cases/undo.vue   |  3 +++
 5 files changed, 28 insertions(+)
 create mode 100644 test/cases/undo.vim
 create mode 100644 test/cases/undo.vue

diff --git a/ftplugin/vue.vim b/ftplugin/vue.vim
index aaa6d52..b9f4251 100644
--- a/ftplugin/vue.vim
+++ b/ftplugin/vue.vim
@@ -1,8 +1,12 @@
 if exists("b:did_ftplugin") | finish | endif
 let b:did_ftplugin = 1
 
+let b:undo_ftplugin = (exists('b:undo_ftplugin') ? b:undo_ftplugin.' | ' : '')
+      \ . 'unlet! b:syng_str b:syng_strcom'
+
 if !has('nvim')
   setlocal matchpairs+=<:>
+  let b:undo_ftplugin .= ' | setlocal matchpairs<'
 endif
 
 if exists("loaded_matchit")
@@ -11,6 +15,7 @@ if exists("loaded_matchit")
         \ '<\@<=[ou]l\>[^>]*\%(>\|$\):<\@<=li\>:<\@<=/[ou]l>,' .
         \ '<\@<=dl\>[^>]*\%(>\|$\):<\@<=d[td]\>:<\@<=/dl>,' .
         \ '<\@<=\([^/][^ \t>]*\)[^>]*\%(>\|$\):<\@<=/\1>'
+  let b:undo_ftplugin .= ' | unlet! b:match_ignorecase b:match_words'
 endif
 
 " Indent correctly with template string for vim-javascript/built-in
diff --git a/ftplugin/vue/fold.vim b/ftplugin/vue/fold.vim
index 63a58ae..5be3061 100644
--- a/ftplugin/vue/fold.vim
+++ b/ftplugin/vue/fold.vim
@@ -14,6 +14,8 @@ function! VueFoldMain(...)
 
     setlocal foldexpr=GetVueFold(v:lnum)
     setlocal foldmethod=expr
+    let b:undo_ftplugin = (exists('b:undo_ftplugin') ? b:undo_ftplugin.' | ' : '')
+          \ . 'setlocal foldexpr< foldmethod<'
   endif
 endfunction
 
diff --git a/indent/vue.vim b/indent/vue.vim
index 5f3c60b..710b391 100644
--- a/indent/vue.vim
+++ b/indent/vue.vim
@@ -36,6 +36,7 @@ function! s:SetVueIndent()
   " XML indentkeys
   setlocal indentkeys+=*<Return>,<>>,<<>,/
   setlocal indentexpr=GetVueIndent()
+  let b:undo_indent = 'setlocal indentexpr< indentkeys< smartindent<'
 endfunction
 
 function! s:GetIndentFile(syntax)
diff --git a/test/cases/undo.vim b/test/cases/undo.vim
new file mode 100644
index 0000000..5271406
--- /dev/null
+++ b/test/cases/undo.vim
@@ -0,0 +1,17 @@
+" Undo settings when filetype changes
+let g:vim_vue_plugin_config = {'foldexpr': 1}
+packadd matchit
+
+function! Check()
+  call ExpectEqual(&l:foldmethod, 'expr', 'foldmethod')
+  call ExpectEqual(&l:indentexpr, 'GetVueIndent()', 'indentexpr')
+  call ExpectEqual(exists('b:match_words'), 1, 'b:match_words')
+  setlocal filetype=text
+  call ExpectEqual(&l:foldmethod, 'manual', 'foldmethod after undo')
+  call ExpectEqual(&l:indentexpr, '', 'indentexpr after undo')
+  call ExpectEqual(exists('b:match_words'), 0, 'b:match_words after undo')
+  call ExpectEqual(exists('b:syng_str'), 0, 'b:syng_str after undo')
+  if !has('nvim')
+    call ExpectEqual(&l:matchpairs, &g:matchpairs, 'matchpairs after undo')
+  endif
+endfunction
diff --git a/test/cases/undo.vue b/test/cases/undo.vue
new file mode 100644
index 0000000..8991778
--- /dev/null
+++ b/test/cases/undo.vue
@@ -0,0 +1,3 @@
+<template>
+  <div>x</div>
+</template>