语言包格式错误引起组件崩溃

最近在修正一些运行时错误中，发现了类似的错误模式，例如

打开SYSADMIN后，教师面板无法进入，检查lms/log发现

1 File "/tmp/mako_lms/instructor/instructor_dashboard_2/course_info.html.py", line 141, in render_body
2     link_end='</a>'
3 KeyError: u' link_start '

用户注册后不能发送邮件，也不能跳转到注册成功页面，而邮件却已正确配置。检查lms/log发现

1 Jul 15 12:33:10 i-hjpuo2yh [service_variant=lms][django.request][env:sandbox] ERROR [i-hjpuo2yh  19843] [base.py:213] - Internal Server Error: /create_account
2 Traceback (most recent call last):
3   File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 109, in get_response
4     response = callback(request, *callback_args, **callback_kwargs)
5   File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 77, in wrapped_view
6     return view_func(*args, **kwargs)
7   File "/edx/app/edxapp/edx-platform/common/djangoapps/student/views.py", line 1615, in create_account
8     create_account_with_params(request, post_override or request.POST)
9   File "/edx/app/edxapp/edx-platform/common/djangoapps/student/views.py", line 1534, in create_account_with_params
10     message = render_to_string('emails/activation_email.txt', context)
11   File "/edx/app/edxapp/edx-platform/common/djangoapps/edxmako/shortcuts.py", line 134, in render_to_string
12     return template.render_unicode(**context_dictionary)
13   File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/template.py", line 452, in render_unicode
14     as_unicode=True)
15   File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 807, in _render
16     **_kwargs_for_callable(callable_, data))
17   File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 839, in _render_context
18     _exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
19   File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 865, in _exec_template
20     callable_(context, *args, **kwargs)
21   File "/tmp/mako_lms/emails/activation_email.txt.py", line 51, in render_body
22     platform_name=settings.PLATFORM_NAME
23 KeyError: u' platform_name '

共同的错误提示KeyError。在和社区开发者进行探讨后，认为是模板的问题，于是@wwj718修改了模板文件使组件可运行并提交commit到github。而edX社区的开发者提示这是语言包问题。

1 This looks to me like a translator added spaces into the format placeholder, turning {link_start} into { link_start }. The fix is to remove the spaces in the translation. Removing the placeholder names as you have done will make it impossible to translate this string in the future.
2
3 Can you double-check your translation files to see if there are spaces in the translated string?
4
5 :-1: on merging this change.
6
7
8 PS, the command i18n_tool validate will find errors with all translation files you have, so you can correct them if you wish. On master, all translation files pass this check.

检查mako.po文件发现，的确是翻译者在变量中加入了错误的空格导致：

{link_start} -> { link_start }
{platform_name} -> { platform_name }

凡是错误加入空格的地方,涉及的组件都会出现KeyError错误。

一劳永逸的做法，我们已在transifex修正了目前发现的几十处类似语言包错误并确认审核。重新下载编译语言包即可修正此类错误。