Support changing the current hierarchy root node

autoload/youcompleteme/hierarchy.vim

@@ -49,23 +49,21 @@ endfunction
 
 function! s:MenuFilter( winid, key )
   if a:key == "\<S-Tab>"
-    if s:lines_and_handles[ s:select - 1 ][ 1 ] <= 0 " TODO: switching root not impl
-      call popup_close( s:popup_id, [ s:select - 1, 'resolve_up' ] )
-    endif
+    let will_change_root = s:lines_and_handles[ s:select - 1 ][ 1 ] > 0
+    call popup_close( s:popup_id, [ s:select - 1, 'resolve_up', will_change_root ] )
     return 1
   endif
   if a:key == "\<Tab>"
-    if s:lines_and_handles[ s:select - 1 ][ 1 ] >= 0 " TODO: switching root not impl
-      call popup_close( s:popup_id, [ s:select - 1, 'resolve_down' ] )
-    endif
+    let will_change_root = s:lines_and_handles[ s:select - 1 ][ 1 ] < 0
+    call popup_close( s:popup_id, [ s:select - 1, 'resolve_down', will_change_root ] )
     return 1
   endif
   if a:key == "\<Esc>"
-    call popup_close( s:popup_id, [ s:select - 1, 'cancel' ] )
+    call popup_close( s:popup_id, [ s:select - 1, 'cancel', v:none ] )
     return 1
   endif
   if a:key == "\<CR>"
-    call popup_close( s:popup_id, [ s:select - 1, 'jump' ] )
+    call popup_close( s:popup_id, [ s:select - 1, 'jump', v:none ] )
     return 1
   endif
   if a:key == "\<Up>"
@@ -93,9 +91,9 @@ function! s:MenuCallback( winid, result )
   let operation = a:result[ 1 ]
   let selection = a:result[ 0 ]
   if operation == 'resolve_down'
-    call s:ResolveItem( selection, 'down' )
+    call s:ResolveItem( selection, 'down', a:result[ 2 ] )
   elseif operation == 'resolve_up'
-    call s:ResolveItem( selection, 'up' )
+    call s:ResolveItem( selection, 'up', a:result[ 2 ] )
   else
     if operation == 'jump'
       let handle = s:lines_and_handles[ selection ][ 1 ]
@@ -119,16 +117,20 @@ function! s:SetupMenu()
                   \ 'call cursor( [' . string( s:select ) . ', 1 ] )' )
 endfunction
 
-function! s:ResolveItem( choice, direction )
+function! s:ResolveItem( choice, direction, will_change_root )
   let handle = s:lines_and_handles[ a:choice ][ 1 ]
   if py3eval(
       \ 'ycm_state.ShouldResolveItem( vimsupport.GetIntValue( "handle" ), vim.eval( "a:direction" ) )' )
     let lines_and_handles_with_offset = py3eval(
         \ 'ycm_state.UpdateCurrentHierarchy( ' .
         \ 'vimsupport.GetIntValue( "handle" ), ' .
         \ 'vim.eval( "a:direction" ) )' )
-    let s:select += lines_and_handles_with_offset[ 1 ]
     let s:lines_and_handles = lines_and_handles_with_offset[ 0 ]
+    if a:will_change_root
+      let s:select = 1 + indexof( s:lines_and_handles, { i, v -> v[0][0] =~ "[-+]" } )
+    else
+      let s:select += lines_and_handles_with_offset[ 1 ]
+    endif
   endif
   call s:SetupMenu()
 endfunction

python/ycm/hierarchy_tree.py

@@ -55,17 +55,27 @@ def SetRootNode( self, items, kind : str ):
 
   def UpdateHierarchy( self, handle : int, items, direction : str ):
     current_index = abs( handle ) // 1000000
-    nodes = self._down_nodes if direction == 'down' else self._up_nodes
-    if items:
-      nodes.extend( [
-        HierarchyNode( item,
-                       nodes[ current_index ]._distance_from_root + 1 )
-        for item in items ] )
-      nodes[ current_index ]._references = list(
-          range( len( nodes ) - len( items ),
-                 len( nodes ) ) )
+    if ( ( handle >= 0 and direction == 'down' ) or
+         ( handle <= 0 and direction == 'up' ) ):
+      nodes = self._down_nodes if direction == 'down' else self._up_nodes
+      if items:
+        nodes.extend( [
+          HierarchyNode( item,
+                         nodes[ current_index ]._distance_from_root + 1 )
+          for item in items ] )
+        nodes[ current_index ]._references = list(
+            range( len( nodes ) - len( items ), len( nodes ) ) )
+      else:
+        nodes[ current_index ]._references = []
     else:
-      nodes[ current_index ]._references = []
+      if direction == 'up':
+        current_node = self._down_nodes[ current_index ]
+      else:
+        current_node = self._up_nodes[ current_index ]
+      old_kind = self._kind
+      self.Reset()
+      self.SetRootNode( [ current_node._data ], old_kind )
+      self.UpdateHierarchy( 0, items, direction )
 
 
   def Reset( self ):
@@ -81,29 +91,31 @@ def _HierarchyToLinesHelper( self, refs, use_down_nodes ):
       next_node = nodes[ i ]
       indent = 2 * next_node._distance_from_root
       if i == 0:
-        can_expand = self._down_nodes[ 0 ]._references is None or self._up_nodes[ 0 ]._references is None
+        can_expand = ( self._down_nodes[ 0 ]._references is None or
+                       self._up_nodes[ 0 ]._references is None )
       else:
         can_expand = next_node._references is None
       symbol = '+' if can_expand else '-'
       name = next_node._data[ 'name' ]
       kind = next_node._data[ 'kind' ]
       if use_down_nodes:
         partial_result.extend( [
-          ( ' ' * indent + symbol + kind + ': ' + name + '\t' +
+          ( ' ' * indent + symbol + kind + ': ' + name + 3 * '\t' +
               os.path.split( l[ 'filepath' ] )[ 1 ] + ':' +
-              str( l[ 'line_num' ] ) + '\t' + l[ 'description' ],
+              str( l[ 'line_num' ] ) + 3 * '\t' + l[ 'description' ],
             ( i * 1000000 + j ) )
           for j, l in enumerate( next_node._data[ 'locations' ] ) ] )
       else:
         partial_result.extend( [
-          ( ' ' * indent + symbol + kind + ': ' + name + '\t' +
+          ( ' ' * indent + symbol + kind + ': ' + name + 3 * '\t' +
               os.path.split( l[ 'filepath' ] )[ 1 ] + ':' +
-              str( l[ 'line_num' ] ) + '\t' + l[ 'description' ],
+              str( l[ 'line_num' ] ) + 3 * '\t' + l[ 'description' ],
             ( i * 1000000 + j ) * -1 )
           for j, l in enumerate( next_node._data[ 'locations' ] ) ] )
       if next_node._references:
         partial_result.extend(
-          self._HierarchyToLinesHelper( next_node._references, use_down_nodes ) )
+          self._HierarchyToLinesHelper(
+            next_node._references, use_down_nodes ) )
     return partial_result
 
   def HierarchyToLines( self ):
@@ -126,11 +138,14 @@ def JumpToItem( self, handle : int, command ):
 
   def ShouldResolveItem( self, handle : int, direction : str ):
     node_index = abs( handle ) // 1000000
-    if direction == 'down':
-      node = self._down_nodes[ node_index ]
-    else:
-      node = self._up_nodes[ node_index ]
-    return node._references is None
+    if ( ( handle >= 0 and direction == 'down' ) or
+         ( handle <= 0 and direction == 'up' ) ):
+      if direction == 'down':
+        node = self._down_nodes[ node_index ]
+      else:
+        node = self._up_nodes[ node_index ]
+      return node._references is None
+    return True
 
 
   def ResolveArguments( self, handle : int, direction : str ):