vim-patch:8.0.0702: error in a timer can make Vim unusable #9826

Problem:    An error in a timer can make Vim unusable.
Solution:   Don't set the error flag or exception from a timer.  Stop a timer
            if it causes an error 3 out of 3 times.  Discard an exception
            caused inside a timer.
https://github.com/vim/vim/commit/c577d813b7978345dec4310b2d8f5d5624a681f6

closes #9826

1 files changed, 17 insertions, 0 deletions

diff --git a/src/nvim/testdir/test_timers.vim b/src/nvim/testdir/test_timers.vim
index fe5d61fad4..5b5f001e6b 100644
--- a/src/nvim/testdir/test_timers.vim
+++ b/src/nvim/testdir/test_timers.vim
@@ -200,6 +200,23 @@ func Test_input_in_timer()
   call assert_equal('hello', g:val)
 endfunc
 
+func FuncWithError(timer)
+  let g:call_count += 1
+  if g:call_count == 4
+    return
+  endif
+  doesnotexist
+endfunc
+
+func Test_timer_errors()
+  let g:call_count = 0
+  let timer = timer_start(10, 'FuncWithError', {'repeat': -1})
+  " Timer will be stopped after failing 3 out of 3 times.
+  call WaitFor('g:call_count == 3')
+  sleep 50m
+  call assert_equal(3, g:call_count)
+endfunc
+
 func FuncWithCaughtError(timer)
   let g:call_count += 1
   try