From a2281bd121949f2215ee9257e28e2c0966f3f003 Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Sun, 12 Nov 2017 16:38:09 +1300
Subject: Add guards for presence of b:undo_* var

This variable is not set in older Vims (early 6.x), and I think it's
worth guarding for.
---
 vim/after/ftplugin/html/lint.vim          | 20 ++++++++++++++------
 vim/after/ftplugin/html/tidy.vim          | 18 ++++++++++++------
 vim/after/ftplugin/html/url_link.vim      | 18 ++++++++++++------
 vim/after/ftplugin/mail/format_flowed.vim | 12 ++++++++----
 vim/after/ftplugin/markdown/spell.vim     | 12 ++++++++----
 vim/after/ftplugin/perl/check.vim         | 18 ++++++++++++------
 vim/after/ftplugin/perl/lint.vim          | 18 ++++++++++++------
 vim/after/ftplugin/perl/tidy.vim          | 18 ++++++++++++------
 vim/after/ftplugin/sh/bash_han.vim        | 12 ++++++++----
 vim/after/ftplugin/sh/check.vim           | 24 ++++++++++++++++--------
 vim/after/ftplugin/sh/lint.vim            | 24 ++++++++++++++++--------
 vim/after/ftplugin/sh/posix.vim           |  6 ++++--
 vim/after/ftplugin/text/spell.vim         | 12 ++++++++----
 vim/after/ftplugin/vim/lint.vim           | 18 ++++++++++++------
 vim/after/indent/vim.vim                  |  6 ++++--
 15 files changed, 158 insertions(+), 78 deletions(-)

diff --git a/vim/after/ftplugin/html/lint.vim b/vim/after/ftplugin/html/lint.vim
index f6648056..3ac760ed 100644
--- a/vim/after/ftplugin/html/lint.vim
+++ b/vim/after/ftplugin/html/lint.vim
@@ -4,8 +4,12 @@ if exists('b:did_ftplugin_html_lint') || &compatible
   finish
 endif
 let b:did_ftplugin_html_lint = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_html_lint'
+
+" Initialise undo variable if not already done
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_html_lint'
+endif
 
 " Set up a mapping for the linter, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_html_maps')
@@ -14,16 +18,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_html_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>HtmlLint
         \ :<C-U>write !tidy -errors -quiet<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>HtmlLint'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>HtmlLint'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>HtmlLint')
     nmap <buffer> <unique>
           \ <LocalLeader>l
           \ <Plug>HtmlLint
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>l'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>l'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/html/tidy.vim b/vim/after/ftplugin/html/tidy.vim
index e5d24541..519a7cd6 100644
--- a/vim/after/ftplugin/html/tidy.vim
+++ b/vim/after/ftplugin/html/tidy.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_html_tidy') || &compatible
   finish
 endif
 let b:did_ftplugin_html_tidy = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_html_tidy'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_html_tidy'
+endif
 
 " Set up a mapping for the tidier, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_html_maps')
@@ -14,16 +16,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_html_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>HtmlTidy
         \ :<C-U>%!tidy -quiet<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>HtmlTidy'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>HtmlTidy'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>HtmlTidy')
     nmap <buffer> <unique>
           \ <LocalLeader>t
           \ <Plug>HtmlTidy
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>t'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>t'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/html/url_link.vim b/vim/after/ftplugin/html/url_link.vim
index cb0d6253..4f2d2526 100644
--- a/vim/after/ftplugin/html/url_link.vim
+++ b/vim/after/ftplugin/html/url_link.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_html_url_link') || &compatible
   finish
 endif
 let b:did_ftplugin_html_url_link = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_html_url_link'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_html_url_link'
+endif
 
 " Make a bare URL into a link to itself
 if !exists('*s:UrlLink')
@@ -32,16 +34,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_html_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>HtmlUrlLink
         \ :<C-U>call <SID>HtmlUrlLink()<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>HtmlUrlLink'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>HtmlUrlLink'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>HtmlUrlLink')
     nmap <buffer> <unique>
           \ <LocalLeader>r
           \ <Plug>HtmlUrlLink
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>r'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>r'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/mail/format_flowed.vim b/vim/after/ftplugin/mail/format_flowed.vim
index b1b308fb..040a1a51 100644
--- a/vim/after/ftplugin/mail/format_flowed.vim
+++ b/vim/after/ftplugin/mail/format_flowed.vim
@@ -4,10 +4,14 @@ if exists('b:did_ftplugin_mail_format_flowed') || &compatible
   finish
 endif
 let b:did_ftplugin_mail_format_flowed = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_mail_format_flowed'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_mail_format_flowed'
+endif
 
 " Use trailing whitespace to denote continued paragraph
 setlocal formatoptions+=w
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|setlocal formatoptions<'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|setlocal formatoptions<'
+endif
diff --git a/vim/after/ftplugin/markdown/spell.vim b/vim/after/ftplugin/markdown/spell.vim
index 8f9ce4a4..bb344374 100644
--- a/vim/after/ftplugin/markdown/spell.vim
+++ b/vim/after/ftplugin/markdown/spell.vim
@@ -4,12 +4,16 @@ if exists('b:did_ftplugin_markdown_spell') || &compatible
   finish
 endif
 let b:did_ftplugin_markdown_spell = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_markdown_spell'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_markdown_spell'
+endif
 
 " Spellcheck documents by default
 if has('syntax')
   setlocal spell
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|setlocal spell<'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|setlocal spell<'
+  endif
 endif
diff --git a/vim/after/ftplugin/perl/check.vim b/vim/after/ftplugin/perl/check.vim
index 24a174ff..6b057c82 100644
--- a/vim/after/ftplugin/perl/check.vim
+++ b/vim/after/ftplugin/perl/check.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_perl_check') || &compatible
   finish
 endif
 let b:did_ftplugin_perl_check = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_perl_check'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_perl_check'
+endif
 
 " Set up a mapping for the checker, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_perl_maps')
@@ -14,16 +16,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_perl_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>PerlCheck
         \ :<C-U>write !perl -c<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>PerlCheck'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>PerlCheck'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>PerlCheck')
     nmap <buffer> <unique>
           \ <LocalLeader>c
           \ <Plug>PerlCheck
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>c'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>c'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/perl/lint.vim b/vim/after/ftplugin/perl/lint.vim
index 8f6915f4..86740c81 100644
--- a/vim/after/ftplugin/perl/lint.vim
+++ b/vim/after/ftplugin/perl/lint.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_perl_lint') || &compatible
   finish
 endif
 let b:did_ftplugin_perl_lint = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_perl_lint'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_perl_lint'
+endif
 
 " Set up a mapping for the linter, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_perl_maps')
@@ -14,16 +16,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_perl_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>PerlLint
         \ :<C-U>write !perlcritic<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>PerlLint'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>PerlLint'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>PerlLint')
     nmap <buffer> <unique>
           \ <LocalLeader>l
           \ <Plug>PerlLint
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>l'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>l'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/perl/tidy.vim b/vim/after/ftplugin/perl/tidy.vim
index b2aa25c3..18033a42 100644
--- a/vim/after/ftplugin/perl/tidy.vim
+++ b/vim/after/ftplugin/perl/tidy.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_perl_tidy') || &compatible
   finish
 endif
 let b:did_ftplugin_perl_tidy = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_perl_tidy'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_perl_tidy'
+endif
 
 " Set up a mapping for the tidier, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_perl_maps')
@@ -14,16 +16,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_perl_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>PerlTidy
         \ :<C-U>%!perltidy<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>PerlTidy'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>PerlTidy'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>PerlTidy')
     nmap <buffer> <unique>
           \ <LocalLeader>t
           \ <Plug>PerlTidy
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>t'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>t'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/sh/bash_han.vim b/vim/after/ftplugin/sh/bash_han.vim
index c1997d7e..a160165c 100644
--- a/vim/after/ftplugin/sh/bash_han.vim
+++ b/vim/after/ftplugin/sh/bash_han.vim
@@ -4,12 +4,16 @@ if exists('b:did_ftplugin_sh_bash_han') || &compatible
   finish
 endif
 let b:did_ftplugin_sh_bash_han = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_sh_bash_han'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_sh_bash_han'
+endif
 
 " Use han(1df) as a man(1) wrapper for Bash files if available
 if exists('b:is_bash') && executable('han')
   setlocal keywordprg=han
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|setlocal keywordprg<'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|setlocal keywordprg<'
+  endif
 endif
diff --git a/vim/after/ftplugin/sh/check.vim b/vim/after/ftplugin/sh/check.vim
index 5000137d..334ec1db 100644
--- a/vim/after/ftplugin/sh/check.vim
+++ b/vim/after/ftplugin/sh/check.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_sh_check') || &compatible
   finish
 endif
 let b:did_ftplugin_sh_check = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_sh_check'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_sh_check'
+endif
 
 " Choose checker based on shell family
 if exists('b:is_bash')
@@ -15,8 +17,10 @@ elseif exists('b:is_kornshell')
 else
   let b:sh_check = 'write !sh -n'
 endif
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:sh_check'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:sh_check'
+endif
 
 " Set up a mapping for the checker, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_sh_maps')
@@ -25,16 +29,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_sh_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>ShCheck
         \ :<C-U>execute b:sh_check<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>ShCheck'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>ShCheck'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>ShCheck')
     nmap <buffer> <unique>
           \ <LocalLeader>c
           \ <Plug>ShCheck
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>c'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>c'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/sh/lint.vim b/vim/after/ftplugin/sh/lint.vim
index b6377966..8745a31e 100644
--- a/vim/after/ftplugin/sh/lint.vim
+++ b/vim/after/ftplugin/sh/lint.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_sh_lint') || &compatible
   finish
 endif
 let b:did_ftplugin_sh_lint = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_sh_lint'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_sh_lint'
+endif
 
 " Choose linter based on shell family
 if exists('b:is_bash')
@@ -15,8 +17,10 @@ elseif exists('b:is_kornshell')
 else
   let b:sh_lint = 'write !shellcheck -e SC1090 -s sh -'
 endif
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:sh_lint'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:sh_lint'
+endif
 
 " Set up a mapping for the linter, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_sh_maps')
@@ -25,16 +29,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_sh_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>ShLint
         \ :<C-U>execute b:sh_lint<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>ShLint'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>ShLint'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>ShLint')
     nmap <buffer> <unique>
           \ <LocalLeader>l
           \ <Plug>ShLint
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>l'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>l'
+    endif
   endif
 
 endif
diff --git a/vim/after/ftplugin/sh/posix.vim b/vim/after/ftplugin/sh/posix.vim
index ef6b9b93..a1b2c7ff 100644
--- a/vim/after/ftplugin/sh/posix.vim
+++ b/vim/after/ftplugin/sh/posix.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_sh_posix') || &compatible
   finish
 endif
 let b:did_ftplugin_sh_posix = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_sh_posix'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_sh_posix'
+endif
 
 "
 " If we have a #!/bin/sh shebang and filetype.vim determined we were neither
diff --git a/vim/after/ftplugin/text/spell.vim b/vim/after/ftplugin/text/spell.vim
index 107723e5..322090ca 100644
--- a/vim/after/ftplugin/text/spell.vim
+++ b/vim/after/ftplugin/text/spell.vim
@@ -4,12 +4,16 @@ if exists('b:did_ftplugin_text_spell') || &compatible
   finish
 endif
 let b:did_ftplugin_text_spell = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_text_spell'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_text_spell'
+endif
 
 " Spellcheck documents by default
 if has('syntax')
   setlocal spell
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|setlocal spell<'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|setlocal spell<'
+  endif
 endif
diff --git a/vim/after/ftplugin/vim/lint.vim b/vim/after/ftplugin/vim/lint.vim
index 5e4ea601..1b557593 100644
--- a/vim/after/ftplugin/vim/lint.vim
+++ b/vim/after/ftplugin/vim/lint.vim
@@ -4,8 +4,10 @@ if exists('b:did_ftplugin_vim_lint') || &compatible
   finish
 endif
 let b:did_ftplugin_vim_lint = 1
-let b:undo_ftplugin = b:undo_ftplugin
-      \ . '|unlet b:did_ftplugin_vim_lint'
+if exists('b:undo_ftplugin')
+  let b:undo_ftplugin = b:undo_ftplugin
+        \ . '|unlet b:did_ftplugin_vim_lint'
+endif
 
 " Set up a mapping for the linter, if we're allowed
 if !exists('g:no_plugin_maps') && !exists('g:no_vim_maps')
@@ -14,16 +16,20 @@ if !exists('g:no_plugin_maps') && !exists('g:no_vim_maps')
   nnoremap <buffer> <silent> <unique>
         \ <Plug>VimLint
         \ :<C-U>write !vint -s /dev/stdin<CR>
-  let b:undo_ftplugin = b:undo_ftplugin
-        \ . '|nunmap <buffer> <Plug>VimLint'
+  if exists('b:undo_ftplugin')
+    let b:undo_ftplugin = b:undo_ftplugin
+          \ . '|nunmap <buffer> <Plug>VimLint'
+  endif
 
   " If there isn't a key mapping already, use a default one
   if !hasmapto('<Plug>VimLint')
     nmap <buffer> <unique>
           \ <LocalLeader>l
           \ <Plug>VimLint
-    let b:undo_ftplugin = b:undo_ftplugin
-          \ . '|nunmap <buffer> <LocalLeader>l'
+    if exists('b:undo_ftplugin')
+      let b:undo_ftplugin = b:undo_ftplugin
+            \ . '|nunmap <buffer> <LocalLeader>l'
+    endif
   endif
 
 endif
diff --git a/vim/after/indent/vim.vim b/vim/after/indent/vim.vim
index b87964a4..0cb1d397 100644
--- a/vim/after/indent/vim.vim
+++ b/vim/after/indent/vim.vim
@@ -1,5 +1,7 @@
 " Observe VimL conventions for two-space indents
 setlocal shiftwidth=2
 setlocal softtabstop=2
-let b:undo_indent = b:undo_indent
-      \ . '|setlocal shiftwidth< softtabstop<'
+if exists('b:undo_indent')
+  let b:undo_indent = b:undo_indent
+        \ . '|setlocal shiftwidth< softtabstop<'
+endif
-- 
cgit v1.2.3