patch 8.1.0143: matchit and matchparen don't handle E363v8.1.0143

Problem:    Matchit and matchparen don't handle E363.
Solution:   Catch the E363 error. (Christian Brabandt)

1 files changed, 22 insertions, 12 deletions

diff --git a/runtime/plugin/matchparen.vim b/runtime/plugin/matchparen.vim
index d53fb22df0..65b9fe57bf 100644
--- a/runtime/plugin/matchparen.vim
+++ b/runtime/plugin/matchparen.vim
@@ -1,6 +1,6 @@
 " Vim plugin for showing matching parens
 " Maintainer:  Bram Moolenaar <Bram@vim.org>
-" Last Change: 2018 Jun 23
+" Last Change: 2018 Jul 3
 
 " Exit quickly when:
 " - this plugin was already loaded (or disabled)
@@ -103,18 +103,28 @@ function! s:Highlight_Matching_Pair()
     call cursor(c_lnum, c_col - before)
   endif
 
-  " Build an expression that detects whether the current cursor position is in
-  " certain syntax types (string, comment, etc.), for use as searchpairpos()'s
-  " skip argument.
-  " We match "escape" for special items, such as lispEscapeSpecial.
-  let s_skip = '!empty(filter(map(synstack(line("."), col(".")), ''synIDattr(v:val, "name")''), ' .
+  if !has("syntax") || !exists("g:syntax_on")
+    let s_skip = "0"
+  else
+    " Build an expression that detects whether the current cursor position is
+    " in certain syntax types (string, comment, etc.), for use as
+    " searchpairpos()'s skip argument.
+    " We match "escape" for special items, such as lispEscapeSpecial.
+    let s_skip = '!empty(filter(map(synstack(line("."), col(".")), ''synIDattr(v:val, "name")''), ' .
 	\ '''v:val =~? "string\\|character\\|singlequote\\|escape\\|comment"''))'
-  " If executing the expression determines that the cursor is currently in
-  " one of the syntax types, then we want searchpairpos() to find the pair
-  " within those syntax types (i.e., not skip).  Otherwise, the cursor is
-  " outside of the syntax types and s_skip should keep its value so we skip any
-  " matching pair inside the syntax types.
-  execute 'if' s_skip '| let s_skip = "0" | endif'
+    " If executing the expression determines that the cursor is currently in
+    " one of the syntax types, then we want searchpairpos() to find the pair
+    " within those syntax types (i.e., not skip).  Otherwise, the cursor is
+    " outside of the syntax types and s_skip should keep its value so we skip
+    " any matching pair inside the syntax types.
+    " Catch if this throws E363: pattern uses more memory than 'maxmempattern'.
+    try
+      execute 'if ' . s_skip . ' | let s_skip = "0" | endif'
+    catch /^Vim\%((\a\+)\)\=:E363/
+      " We won't find anything, so skip searching, should keep Vim responsive.
+      return
+    endtry
+  endif
 
   " Limit the search to lines visible in the window.
   let stoplinebottom = line('w$')