🐛 Properly handle Element#document # => nil

- Fixes #260

Author: pboling

lib/rexml/child.rb

@@ -83,13 +83,12 @@ def previous_sibling=(other)
     # Returns:: the document this child belongs to, or nil if this child
     # belongs to no document
     def document
-      return parent.document unless parent.nil?
-      nil
+      parent&.document
     end
 
     # This doesn't yet handle encodings
     def bytes
-      document.encoding
+      document&.encoding
 
       to_s
     end

lib/rexml/element.rb

@@ -473,8 +473,7 @@ def root
     # Related: #root, #root_node.
     #
     def document
-      rt = root
-      rt.parent if rt
+      root&.parent
     end
 
     # :call-seq:
@@ -2325,11 +2324,11 @@ def get_attribute( name )
             return attr
           end
         end
-        element_document = @element.document
-        if element_document and element_document.doctype
+        doctype = @element.document&.doctype
+        if doctype
           expn = @element.expanded_name
-          expn = element_document.doctype.name if expn.size == 0
-          attr_val = element_document.doctype.attribute_of(expn, name)
+          expn = doctype.name if expn.size == 0
+          attr_val = doctype.attribute_of(expn, name)
           return Attribute.new( name, attr_val ) if attr_val
         end
         return nil
@@ -2371,8 +2370,8 @@ def []=( name, value )
       end
 
       unless value.kind_of? Attribute
-        if @element.document and @element.document.doctype
-          value = Text::normalize( value, @element.document.doctype )
+        if @element.document and (doctype = @element.document&.doctype)
+          value = Text::normalize( value, doctype )
         else
           value = Text::normalize( value, nil )
         end
@@ -2390,7 +2389,7 @@ def []=( name, value )
       else
         store value.name, value
       end
-      return @element
+      @element
     end
 
     # :call-seq:
@@ -2409,10 +2408,10 @@ def prefixes
       each_attribute do |attribute|
         ns << attribute.name if attribute.prefix == 'xmlns'
       end
-      if @element.document and @element.document.doctype
+      if @element.document and (doctype = @element.document&.doctype)
         expn = @element.expanded_name
-        expn = @element.document.doctype.name if expn.size == 0
-        @element.document.doctype.attributes_of(expn).each {
+        expn = doctype.name if expn.size == 0
+        doctype.attributes_of(expn).each {
           |attribute|
           ns << attribute.name if attribute.prefix == 'xmlns'
         }
@@ -2434,10 +2433,10 @@ def namespaces
       each_attribute do |attribute|
         namespaces[attribute.name] = attribute.value if attribute.prefix == 'xmlns' or attribute.name == 'xmlns'
       end
-      if @element.document and @element.document.doctype
+      if @element.document and (doctype = @element.document&.doctype)
         expn = @element.expanded_name
-        expn = @element.document.doctype.name if expn.size == 0
-        @element.document.doctype.attributes_of(expn).each {
+        expn = doctype.name if expn.size == 0
+        doctype.attributes_of(expn).each {
           |attribute|
           namespaces[attribute.name] = attribute.value if attribute.prefix == 'xmlns' or attribute.name == 'xmlns'
         }

lib/rexml/text.rb

@@ -201,8 +201,7 @@ def <=>( other )
 
     def doctype
       if @parent
-        doc = @parent.document
-        doc.doctype if doc
+        @parent.document&.doctype
       end
     end
 

lib/rexml/xpath_parser.rb

@@ -84,7 +84,7 @@ def parse path, node
         node = node.first
       end
 
-      node.document.__send__(:enable_cache) do
+      node.document&.__send__(:enable_cache) do
         match( path_stack, node )
       end
     end