我的 RoR 应用程序中有一个模型让我发疯。
我想为其添加一个新属性，但它只是不允许我这样做 这是代码
class Issue < ActiveRecord::Base
attr_accessible :page_count, # -> unexpected parameter value 'page_count'
:publication
....
end
有问题的属性在迁移文件中有相应的字段。
如果我手动添加访问器方法，错误就会消失。
attr_reader :page_count
attr_writer :page_count
def page_count
@page_count
end
def page_count=(value)
@page_count = value
end
问题是，我不明白为什么会发生这种情况，因为我在这个模型类上有许多其他属性并且碰巧没有这个问题。
我正在使用 rails 3.2.9 和 ruby 1.9.3p194（2012-04-20 修订版 35410）[x86_64-darwin11.4.0]
根据要求，这是完整的堆栈跟踪。我正在使用具有大量捆绑宝石的 activeadmin。
activemodel (3.2.9) lib/active_model/attribute_methods.rb:407:in `method_missing'
activerecord (3.2.9) lib/active_record/attribute_methods.rb:149:in `method_missing'
actionpack (3.2.9) lib/action_view/helpers/form_helper.rb:1161:in `value_before_type_cast'
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actionpack (3.2.9) lib/action_view/helpers/form_helper.rb:692:in `text_field'
actionpack (3.2.9) lib/action_view/helpers/form_helper.rb:1284:in `text_field'
formtastic (2.2.1) lib/formtastic/inputs/base/stringish.rb:10:in `block in to_html'
actionpack (3.2.9) lib/action_view/helpers/capture_helper.rb:40:in `block in capture'
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haml (4.0.0) lib/haml/helpers/action_view_xss_mods.rb:5:in `with_output_buffer_with_haml_xss'
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activeadmin (0.5.0) lib/active_admin/form_builder.rb:173:in `with_new_form_buffer'
activeadmin (0.5.0) lib/active_admin/form_builder.rb:22:in `input'
app/admin/issues.rb:17:in `block (3 levels) in <top (required)>'
actionpack (3.2.9) lib/action_view/helpers/capture_helper.rb:40:in `block in capture'
actionpack (3.2.9) lib/action_view/helpers/capture_helper.rb:187:in `with_output_buffer'
haml (4.0.0) lib/haml/helpers/action_view_xss_mods.rb:5:in `with_output_buffer_with_haml_xss'
actionpack (3.2.9) lib/action_view/helpers/capture_helper.rb:40:in `capture'
haml (4.0.0) lib/haml/helpers/action_view_mods.rb:59:in `capture_with_haml'
formtastic (2.2.1) lib/formtastic/helpers/fieldset_wrapper.rb:32:in `field_set_and_list_wrapping'
formtastic (2.2.1) lib/formtastic/helpers/inputs_helper.rb:292:in `inputs'
activeadmin (0.5.0) lib/active_admin/form_builder.rb:14:in `block in inputs'
activeadmin (0.5.0) lib/active_admin/form_builder.rb:173:in `with_new_form_buffer'
activeadmin (0.5.0) lib/active_admin/form_builder.rb:14:in `inputs'
app/admin/issues.rb:13:in `block (2 levels) in <top (required)>'
activeadmin (0.5.0) lib/active_admin/views/pages/form.rb:23:in `instance_exec'
activeadmin (0.5.0) lib/active_admin/views/pages/form.rb:23:in `block in main_content'
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haml (4.0.0) lib/haml/helpers/action_view_xss_mods.rb:5:in `with_output_buffer_with_haml_xss'
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haml (4.0.0) lib/haml/helpers/action_view_mods.rb:59:in `capture_with_haml'
actionpack (3.2.9) lib/action_view/helpers/form_helper.rb:607:in `fields_for'
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haml (4.0.0) lib/haml/helpers/action_view_xss_mods.rb:28:in `form_for_with_haml_xss'
formtastic (2.2.1) lib/formtastic/helpers/form_helper.rb:161:in `block in semantic_form_for'
formtastic (2.2.1) lib/formtastic/helpers/form_helper.rb:192:in `with_custom_field_error_proc'
formtastic (2.2.1) lib/formtastic/helpers/form_helper.rb:160:in `semantic_form_for'
activeadmin (0.5.0) lib/active_admin/view_helpers/form_helper.rb:8:in `active_admin_form_for'
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activeadmin (0.5.0) lib/active_admin/views/pages/form.rb:22:in `main_content'
activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:78:in `block (2 levels) in build_main_content_wrapper'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:31:in `block in build_tag'
arbre (1.0.1) lib/arbre/context.rb:92:in `with_current_arbre_element'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:49:in `with_current_arbre_element'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:26:in `build_tag'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:39:in `insert_tag'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:18:in `div'
activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:77:in `block in build_main_content_wrapper'
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arbre (1.0.1) lib/arbre/element/builder_methods.rb:18:in `div'
activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:59:in `build_page_content'
activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:42:in `block (2 levels) in build_page'
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arbre (1.0.1) lib/arbre/context.rb:92:in `with_current_arbre_element'
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activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:39:in `block in build_page'
arbre (1.0.1) lib/arbre/context.rb:92:in `with_current_arbre_element'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:49:in `with_current_arbre_element'
activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:38:in `build_page'
activeadmin (0.5.0) lib/active_admin/views/pages/base.rb:10:in `build'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:30:in `block in build_tag'
arbre (1.0.1) lib/arbre/context.rb:92:in `with_current_arbre_element'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:26:in `build_tag'
arbre (1.0.1) lib/arbre/element/builder_methods.rb:39:in `insert_tag'
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arbre (1.0.1) lib/arbre/context.rb:45:in `instance_eval'
arbre (1.0.1) lib/arbre/context.rb:45:in `initialize'
activeadmin (0.5.0) app/views/active_admin/resource/new.html.arb:1:in `new'
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activesupport (3.2.9) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
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