do not reuse the context dictionary (fix #28) (#29)

Author: bicycle1885

src/document.jl

@@ -139,7 +139,8 @@ Read `filename` and create an XML document.
 """
 function readxml(filename::AbstractString)
     encoding = C_NULL
-    options = 0
+    # Do not reuse the context dictionary.
+    options = 1 << 12
     doc_ptr = @check ccall(
         (:xmlReadFile, libxml2),
         Ptr{_Node},

src/node.jl

@@ -825,10 +825,12 @@ function unlink!(node::Node)
         Void,
         (Ptr{Void},),
         node.ptr)
+    ccall(
+        (:xmlSetTreeDoc, libxml2),
+        Void,
+        (Ptr{Void}, Ptr{Void}),
+        node.ptr, C_NULL)
     update_owners!(node, node)
-    # Unlinking must remove documents as well because
-    # a node can free resources its document owns.
-    unset_documents!(node)
     return node
 end
 
@@ -874,16 +876,6 @@ function update_owners!(root, new_owner)
     end
 end
 
-# Unset the .doc field of the `root` tree.
-function unset_documents!(root)
-    offset = fieldoffset(_Node, 9)
-    traverse_tree(root.ptr) do node_ptr
-        unsafe_store!(
-            convert(Ptr{UInt}, node_ptr + offset),
-            convert(UInt, C_NULL))
-    end
-end
-
 
 # Utils
 # -----

test/runtests.jl

@@ -971,6 +971,13 @@ end
     target = firstelement(root(doc2))
     @test_throws ArgumentError linknext!(target, child)
     @test_throws ArgumentError linkprev!(target, child)
+
+    # Issue #28
+    doc = readxml(joinpath(dirname(@__FILE__), "sample1.xml"))
+    unlink!(firstelement(root(doc)))
+    # No need to check the return value because this is a bug of memory
+    # management. Regression will be detected as a SIGABRT.
+    @test true
 end
 
 @testset "Validation" begin