model: make TreeNode.fetch work properly with parent references

2 files changed, 14 insertions, 6 deletions

diff --git a/acf2/model/node.lua b/acf2/model/node.lua
index 2d9aa98..bebad93 100644
--- a/acf2/model/node.lua
+++ b/acf2/model/node.lua
@@ -128,6 +128,15 @@ function M.TreeNode:fetch(path, create)
    if #path == 0 then return self end
 
    local name = path[1]
+   table.remove(path, 1)
+
+   if name == pth.up then
+      if not mt.parent then
+	 raise(mt.path, 'Root object does not have parent')
+      end
+      return M.TreeNode.fetch(mt.parent, path, create)
+   end
+
    if not mt.member(name) then
       raise(mt.path, 'Member does not exist: '..name)
    end
@@ -135,14 +144,13 @@ function M.TreeNode:fetch(path, create)
    local options = {}
    if create then
       options.create = true
-      if #path == 1 then options.dereference = false end
+      if #path == 0 then options.dereference = false end
    end
    local next = mt.get(name, options)
-   if next == nil and (not create or #path > 1) then
+   if next == nil and (not create or #path > 0) then
       raise(mt.path, 'Subordinate does not exist: '..name)
    end
 
-   table.remove(path, 1)
    if #path > 0 and type(next) ~= 'table' then
       raise(pth.join(mt.path, name), 'Is a primitive value')
    end
diff --git a/acf2/path.lua b/acf2/path.lua
index d080c42..431f0df 100644
--- a/acf2/path.lua
+++ b/acf2/path.lua
@@ -8,9 +8,9 @@ local M = {}
 local map = require('acf2.util').map
 
 
-local up = {}
+M.up = {}
 M.wildcard = {}
-local special = {['..']=up, ['*']=M.wildcard}
+local special = {['..']=M.up, ['*']=M.wildcard}
 
 
 function M.is_absolute(path) return path:sub(1, 1) == '/' end
@@ -93,7 +93,7 @@ function M.to_absolute(path, base)
    local comps = M.split(path)
    local i = 1
    while i <= #comps do
-      if comps[i] == up then
+      if comps[i] == M.up then
 	 if i == 1 then error('Invalid path: '..path) end
 	 table.remove(comps, i - 1)
 	 table.remove(comps, i - 1)