improve add_button_to_query error message

src/mechanize/form.cr

@@ -20,7 +20,7 @@ class MechanizeCr::Form
   getter name         : String
   property action     : String
 
-  def initialize(node : Node | Myhtml::Node)
+  def initialize(node : Node | Myhtml::Node, page : Page? = nil)
     @enctype          = node.fetch("enctype", "application/x-www-form-urlencoded")
     @node             = node
     @fields           = Array(FormContent::Field).new
@@ -31,7 +31,7 @@ class MechanizeCr::Form
     @method           = node.fetch("method", "GET").upcase
     @name             = node.fetch("name", "")
     @clicked_buttons  = Array(FormContent::Button).new
-    #@page             = page
+    @page             = page
     #@mech             = mech
 
     #@encoding = node['accept-charset'] || (page && page.encoding) || nil
@@ -156,9 +156,9 @@ class MechanizeCr::Form
   # submitted with multiple buttons, pass each button to this method.
   def add_button_to_query(button)
     unless button.form_node == @node
-      #message = ""
-      #  "#{button.inspect} does not belong to the same page as " \
-      #  "the form #{@name.inspect} in #{@page.uri}"
+      message = ""
+        "#{button.inspect} does not belong to the same page as " \
+        "the form #{@name.inspect} in #{@page.try &.uri}"
       message = "not a valid button"
       raise ArgumentError.new(message)
     end

src/mechanize/form/field.cr

@@ -26,4 +26,11 @@ class MechanizeCr::FormContent::Field
   def dom_class
     node.fetch("class", "")
   end
+
+  def inspect # :nodoc:
+    "[%s:0x%x type: %s name: %s value: %s]" % [
+      self.class.name.sub(/Mechanize::FormContent::/, "").downcase,
+      object_id, type, name, value
+    ]
+  end
 end

src/mechanize/page.cr

@@ -24,7 +24,7 @@ class MechanizeCr::Page < MechanizeCr::File
 
   def forms
     forms = css("form").map do |html_form|
-      form = Form.new(html_form)
+      form = Form.new(html_form, self)
       form.action ||= @uri.to_s
       form
     end.to_a