Work around vim bugs in appending to buffers

python3/vimspector/utils.py

@@ -202,6 +202,7 @@ def AskForInput( prompt ):
 
 
 def AppendToBuffer( buf, line_or_lines, modified=False ):
+  try:
     # After clearing the buffer (using buf[:] = None) there is always a single
     # empty line in the buffer object and no "is empty" method.
     if len( buf ) > 1 or buf[ 0 ]:
@@ -213,7 +214,15 @@ def AppendToBuffer( buf, line_or_lines, modified=False ):
     else:
       line = 1
       buf[:] = line_or_lines
-
+  except vim.error as e:
+    # There seem to be a lot of Vim bugs that lead to E351, whose help says that
+    # this is an internal error. Ignore the error, but write a trace to the log.
+    if 'E315' in str( e ):
+      logging.getLogger( __name__ ).exception(
+        'Internal error while updating buffer' )
+    else:
+      raise e
+  finally:
     if not modified:
       buf.options[ 'modified' ] = False
 
@@ -221,6 +230,7 @@ def AppendToBuffer( buf, line_or_lines, modified=False ):
   return line
 
 
+
 def ClearBuffer( buf ):
   buf[:] = None