:UndoTreeToggle causes E121 and E116

[Xmgplays]

Using :UndoTreeToggle after editing a file generates this error

Error detected while processing function undotree#UndotreeToggle[11]..25[13]..27[55]..23[5]..38[65]..39:   
line   64:
E121: Undefined variable: matchwhat
E116: Invalid arguments for function <SNR>91_log

functionality does not seem to be affected.

Reproduced this using this config on neovim v0.4.3:

call plug#begin('~/.nvim/plugged')
Plug 'mbbil/undotree'
call plug#end()

Update: Same config does not cause error in vim

[trankien386]

I also faced this issue in neovim and not in vim.

Above errors occurred when i do these actions: Opening UndoTree window using :UndoTreeToggle and :UndoTreeShow, opening Diff panel, toggling relative timestamp and undoing, redoing while UndoTree window open.

Strange enough, turn off the diff panel completely makes errors disappear when doing those actions.

let g:undotree_DiffAutoOpen = 0

Seems like the diff panel are the reason causing the error.

[freddiehaddad]

I think there's a bug with the scope of the variable matchwhat and the following: undotree_HighlightChangedWithSign.

I did the following in my init.lua:

vim.g.undotree_HighlightChangedWithSign = 0

And modifed undotree.vim adding let matchwhat = '' just before the loop on line 1173 because on line 1205 the variable is out of scope.

git diff
diff --git a/autoload/undotree.vim b/autoload/undotree.vim
index 7e74ea6..477940e 100644
--- a/autoload/undotree.vim
+++ b/autoload/undotree.vim
@@ -1170,6 +1170,7 @@ function! s:diffpanel.ParseDiff(diffresult, targetBufnr) abort
     let w:undotree_diffsigns = 0
     let lineNr = 0
     let l:lastLine = line('$')
+    let matchwhat = ''
     for line in a:diffresult
         let matchnum = matchstr(line,'^[0-9,\,]*[acd]\zs\d*\ze')
         if !empty(matchnum)
@@ -1202,7 +1203,7 @@ function! s:diffpanel.ParseDiff(diffresult, targetBufnr) abort
 
         let self.changes.add += 1
         if g:undotree_HighlightChangedText
-            if matchtext != ' '
+            if matchtext != ' ' && matchwhat != ''
                 let matchtext = '\%'.lineNr.'l\V'.escape(matchtext[1:],'"\') "remove beginning space.
                 call s:log("matchadd(".matchwhat.") ->  ".matchtext)
                 call add(w:undotree_diffmatches,matchadd((matchwhat ==# 'a' ? g:undotree_HighlightSyntaxAdd : g:undotree_HighlightSyntaxChange),matchtext))

[freddiehaddad]

I will also add that switch from FISH to Zsh fixed everything without my changes. Now I'm thinking my problem was something to do with the way FISH works.

@Xmgplays Curious what shell you're using.

[gmile]

Seeing an issue related to matchwhat variable, same E121 error code (context: following the short tutorial video from Primagen). And FWIW, I'm using fish-shell on macOS too.

[fmpisantos]

In macos when using zsh shell you need the following:
vim.cmd('set shellquote=')
vim.cmd('set shellxquote=')