YouCompleteMe workaround: explicitly include system include dirs

tools/vim/chromium.ycm_extra_conf.py

Index: tools/vim/chromium.ycm_extra_conf.py
diff --git a/tools/vim/chromium.ycm_extra_conf.py b/tools/vim/chromium.ycm_extra_conf.py
index bb988388d4c0c69413d501cdcca320848d0c01e5..9b1d5569e509d169aa9883b550e072d6223c4352 100644
--- a/tools/vim/chromium.ycm_extra_conf.py
+++ b/tools/vim/chromium.ycm_extra_conf.py
@@ -39,10 +39,39 @@
 
 import os
 import os.path
+import re
 import subprocess
 import sys
 
 
+def SystemIncludeDirectoryFlags():
+  """Determines compile flags to include the system include directories.
+
+  Use as a workaround for https://github.com/Valloric/YouCompleteMe/issues/303
+
+  Returns:
+    (List of Strings) Compile flags to append.
+  """
+  try:
+    with open(os.devnull, 'rb') as DEVNULL:
+      output = subprocess.check_output(['clang', '-v', '-E', '-x', 'c++', '-'],
+                                       stdin=DEVNULL, stderr=subprocess.STDOUT)
+  except (FileNotFoundError, subprocess.CalledProcessError):
+    return []
+  includes_regex = r'#include <\.\.\.> search starts here:' \
+                   r'(.*?)End of search list\.'
+  includes = re.search(includes_regex, output.decode(), re.DOTALL).group(1)
+  flags = []
+  for path in includes.split('\n'):
+    path = path.strip()
+    if os.path.isdir(path):

[eroman, 2015/01/21 02:33:00]

You may want to skip if len(path) == 0

(Haven't though through the regexp enough, but might be possible with the
splitting and whitespace stripping?)

[johnme, 2015/01/21 12:23:35]

It was possible, but os.path.isdir('') returns False so it doesn't matter. I've
tweaked the regex and replaced split('\n') with splitlines() so we won't
needlessly call isdir with an empty string (and to avoid hardcoding unix line
endings).

+      flags.append('-isystem')
+      flags.append(path)
+  return flags
+
+
+_system_include_flags = SystemIncludeDirectoryFlags()
+
 # Flags from YCM's default config.
 flags = [
 '-DUSE_CLANG_COMPLETER',
@@ -196,7 +225,7 @@ def FlagsForFile(filename):
   chrome_root = FindChromeSrcFromFilename(filename)
   chrome_flags = GetClangCommandFromNinjaForFilename(chrome_root,
                                                      filename)
-  final_flags = flags + chrome_flags
+  final_flags = flags + chrome_flags + _system_include_flags
 
   return {
     'flags': final_flags,