From 3f365fd9a8c387376f5ad070ffe73c148b728336 Mon Sep 17 00:00:00 2001
From: Nate Fischer <ntfschr@google.com>
Date: Thu, 18 Feb 2021 10:00:12 -0800
Subject: [PATCH] Add --clean to avoid loading ftplugins

This uses vim's '--clean' switch to avoid loading ftplugins, since this
can affect behavior during vroom tests. This switch seems to avoid the
issue in my local testing, whereas other things ('-i NONE',
'--noplugin', etc.) don't seem to have the same effect. This falls back
to trying without the '--clean' switch if vim fails to start up.

I can't get vroom running in '--neovim' mode (nvim 0.4.4), so this
doesn't attempt to address the issue in the neovim code path. neovim
appears to define '--clean' differently from vim, so it's possible
neovim may require a different fix.

I verified this still respects vroom's '--vimrc' switch while having the
desired behavior of avoiding plugins.

Fixes #105
---
 vroom/vim.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/vroom/vim.py b/vroom/vim.py
index f295f65..4fc4684 100644
--- a/vroom/vim.py
+++ b/vroom/vim.py
@@ -92,8 +92,12 @@ class Communicator(object):
   def __init__(self, args, env, writer):
     self.writer = writer.commands
     self.args = args
+    # The order of switches matters. '--clean' will prevent vim from loading any
+    # plugins from ~/.vim/, but it also sets '-u DEFAULTS'. We supply '-u' after
+    # to force vim to take our '-u' value (while still avoiding plugins).
     self.start_command = [
         'vim',
+        '--clean',
         '-u', args.vimrc,
         '--servername', args.servername,
         '-c', 'set shell=' + args.shell,
@@ -120,6 +124,13 @@ def Start(self):
     # still has a _vim attribute it can query for details.
     self.process = subprocess.Popen(self.start_command, env=self.env)
     time.sleep(self.args.startuptime)
+    if self.process.poll() is not None and self.process.poll() != 0:
+      # If vim exited this quickly, it probably means we passed a switch it
+      # doesn't recognize. Try again without the '--clean' switch since this is
+      # new in 8.0.1554+.
+      self.start_command.remove('--clean')
+      self.process = subprocess.Popen(self.start_command, env=self.env)
+      time.sleep(self.args.startuptime)
 
   def _IsCurrentDisplayUsable(self):
     """Check whether vim fails using the current configured display."""