prevent deletion of objects referred to by other objects

1 files changed, 16 insertions, 2 deletions

diff --git a/acf/transaction/init.lua b/acf/transaction/init.lua
index a76e7bf..76a8d47 100644
--- a/acf/transaction/init.lua
+++ b/acf/transaction/init.lua
@@ -6,7 +6,7 @@ See LICENSE file for license details
 module(..., package.seeall)
 
 local ErrorDict = require('acf.error').ErrorDict
-local RootModel = require('acf.model.root').RootModel
+local root = require('acf.model.root')
 local object = require('acf.object')
 local pth = require('acf.path')
 local be_mod = require('acf.transaction.backend')
@@ -46,7 +46,7 @@ function Transaction:init(backend, validate)
    self.validate = validate
    self.validable = {}
 
-   self.root = RootModel(self)
+   self.root = root.RootModel(self)
 end
 
 function Transaction:check()
@@ -94,6 +94,20 @@ function Transaction:_set_multiple(mods)
 
       local delete = value == nil
 
+      if delete then
+	 -- assume one-level refs for now
+	 local top = root.topology(ppath)
+	 if top then
+	    local errors = ErrorDict()
+	    for _, refs in ipairs(top.referrers) do
+	       for _, ref in ipairs(self.root:search_refs(refs)) do
+		  errors:collect(ref.deleted, ref, path)
+	       end
+	    end
+	    errors:raise()
+	 end
+      end
+
       if type(old) == 'table' then
 	 if delete then
 	    for _, child in ipairs(old) do self:set(pth.join(path, child)) end