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/perl/check.vim | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

(limited to 'vim/after/ftplugin/perl/check.vim')

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
-- 
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