Adding the YcmDebugInfo command

autoload/youcompleteme.vim

@@ -405,6 +405,17 @@ function! youcompleteme#CurrentFileDiagnostics()
 endfunction
 
 
+function! s:DebugInfo()
+  echom "Printing YouCompleteMe debug information..."
+  let debug_info = pyeval( 'ycm_state.DebugInfo()' )
+  for line in split( debug_info, "\n" )
+    echom '-- ' . line
+  endfor
+endfunction
+
+command! YcmDebugInfo call s:DebugInfo()
+
+
 " This is basic vim plugin boilerplate
 let &cpo = s:save_cpo
 unlet s:save_cpo

cpp/ycm/ClangCompleter/ClangUtils.cpp

@@ -196,4 +196,8 @@ Diagnostic DiagnosticWrapToDiagnostic( DiagnosticWrap diagnostic_wrap ) {
   return diagnostic;
 }
 
+std::string ClangVersion() {
+  return CXStringToString( clang_getClangVersion() );
+}
+
 } // namespace YouCompleteMe

cpp/ycm/ClangCompleter/ClangUtils.h

@@ -42,6 +42,8 @@ std::vector< CXUnsavedFile > ToCXUnsavedFiles(
 
 Diagnostic DiagnosticWrapToDiagnostic( DiagnosticWrap diagnostic_wrap );
 
+std::string ClangVersion();
+
 } // namespace YouCompleteMe
 
 #endif /* end of include guard: CLANGUTILS_H_9MVHQLJS */

cpp/ycm/ycm_core.cpp

@@ -20,6 +20,7 @@
 
 #ifdef USE_CLANG_COMPLETER
 #  include "ClangCompleter.h"
+#  include "ClangUtils.h"
 #  include "CompletionData.h"
 #  include "Diagnostic.h"
 #  include "UnsavedFile.h"
@@ -70,6 +71,8 @@ BOOST_PYTHON_MODULE(ycm_core)
     .def( "GetResults", &Future< void >::GetResults );
 
 #ifdef USE_CLANG_COMPLETER
+  def( "ClangVersion", ClangVersion );
+
   class_< Future< AsyncCompletions > >( "FutureCompletions" )
     .def( "ResultsReady", &Future< AsyncCompletions >::ResultsReady )
     .def( "GetResults", &Future< AsyncCompletions >::GetResults );

python/completers/completer.py

@@ -90,3 +90,7 @@ class Completer( object ):
   @abc.abstractmethod
   def ShouldUseNow( self, start_column ):
     pass
+
+
+  def DebugInfo( self ):
+    return ''

python/ycm.py

@@ -23,6 +23,7 @@ import vim
 import utils
 import os
 import sys
+import ycm_core
 from completers.all.identifier_completer import IdentifierCompleter
 
 FILETYPE_SPECIFIC_COMPLETION_TO_DISABLE = vim.eval(
@@ -124,6 +125,28 @@ class YouCompleteMe( object ):
       self.GetFiletypeCompleterForCurrentFile().OnCurrentIdentifierFinished()
 
 
+  def DebugInfo( self ):
+    completers = set( self.filetype_completers.values() )
+    completers.add( self.identcomp )
+    output = []
+    for completer in completers:
+      if not completer:
+        continue
+      debug = completer.DebugInfo()
+      if debug:
+        output.append( debug )
+
+    has_clang_support = ycm_core.HasClangSupport()
+    output.append( 'Has Clang support compiled in: {0}'.format(
+      has_clang_support ) )
+
+    if has_clang_support:
+      output.append( ycm_core.ClangVersion() )
+
+    return '\n'.join( output )
+
+
+
 def _PathToCompletersFolder():
   dir_of_current_script = os.path.dirname( os.path.abspath( __file__ ) )
   return os.path.join( dir_of_current_script, 'completers' )