chameleon: semi misleading template error messages

[castilma]

I'm not sure if this is the right place for this.

if you run the attached server and visit localhost:8080/myroute/foo, you get a template error:

will now serve on port  8080
Traceback (most recent call last):
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/tweens.py", line 12, in _error_handler
    response = request.invoke_exception_view(exc_info)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/view.py", line 756, in invoke_exception_view
    raise HTTPNotFound
pyramid.httpexceptions.HTTPNotFound: The resource could not be found.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.5/wsgiref/handlers.py", line 137, in run
    self.result = application(self.environ, self.start_response)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/router.py", line 270, in __call__
    response = self.execution_policy(environ, self)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/router.py", line 278, in default_execution_policy
    return request.invoke_exception_view(reraise=True)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/view.py", line 755, in invoke_exception_view
    reraise_(*exc_info)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/compat.py", line 148, in reraise
    raise value
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/router.py", line 276, in default_execution_policy
    return router.invoke_request(request)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/router.py", line 249, in invoke_request
    response = handle_request(request)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/tweens.py", line 41, in excview_tween
    response = _error_handler(request, exc)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/tweens.py", line 16, in _error_handler
    reraise(*exc_info)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/compat.py", line 148, in reraise
    raise value
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/tweens.py", line 39, in excview_tween
    response = handler(request)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/router.py", line 156, in handle_request
    view_name
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/view.py", line 642, in _call_view
    response = view_callable(context, request)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/viewderivers.py", line 462, in rendered_view
    request, result, view_inst, context)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/renderers.py", line 435, in render_view
    return self.render_to_response(response, system, request=request)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/renderers.py", line 458, in render_to_response
    result = self.render(value, system_values, request=request)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid/renderers.py", line 454, in render
    result = renderer(value, system_values)
  File "/home/pi/.local/lib/python3.5/site-packages/pyramid_chameleon/zpt.py", line 47, in __call__
    result = self.template(**system)
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/template.py", line 124, in __call__
    return self.render(**kwargs)
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/zpt/template.py", line 297, in render
    return super(PageTemplate, self).render(**_kw)
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/template.py", line 191, in render
    raise_with_traceback(exc, tb)
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/utils.py", line 75, in raise_with_traceback
    raise exc
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/template.py", line 171, in render
    self._render(stream, econtext, rcontext)
  File "index_161d98e17b5a3f24d86304929b34b0af.py", line 200, in render
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/zpt/template.py", line 301, in include
    self._render(*args, **kwargs)
  File "base_9068126ef4690e8b4198d76bc88e1dfb.py", line 305, in render
  File "index_161d98e17b5a3f24d86304929b34b0af.py", line 136, in __fill_content
  File "/home/pi/.local/lib/python3.5/site-packages/chameleon/utils.py", line 406, in __getitem__
    raise NameError(key)
NameError: undecl_name

 - Expression: "pair[0]"
 - Filename:   /home/pi/code/pathbug/project/templates/base.pt
 - Location:   (line 14: col 75)
 - Source:     ... oute/${pair[1]}" tal:content="pair[0]" /></li>
                                                 ^^^^^^^
 - Expression: "load: base.pt"
 - Filename:   /home/pi/code/pathbug/project/templates/index.pt
 - Location:   (line 1: col 23)
 - Source:     <metal:main use-macro="load: base.pt">
                                      ^^^^^^^^^^^^^
 - Arguments:  get_csrf_token: <partial - at 0x75deab70>
               content: some spec content
               request: <Request - at 0x75dd4b90>
               repeat: {...} (0)
               current_spec: sec
               view: <function art_desc at 0x75dd38e8>
               target_language: <NoneType - at 0x3e5788>
               macroname: load: base.pt
               context: <DefaultRootFactory None at 0x75dd4bb0>
               renderer_name: templates/index.pt
               renderer_info: <RendererHelper - at 0x75dd4e50>
               req: <Request - at 0x75dd4b90>
               tuples: <list - at 0x75e47328>
192.168.178.5 - - [16/Feb/2018 00:07:10] "GET /myroute/sec HTTP/1.1" 500 59

the problem is the 'undecl_name' in the file templates/index.pt. The NameError mentions that, but the following info is misleading. It looks like the error is in base.pt in the expression pair[0]. but that is not the case!

I think you only need chameleon, waitress and pyramid to run this project.
bad_err.tar.gz

[digitalresistor]

I'd recommend creating a new GitHub repo with your code in it, so it can be reviewed without downloading a tarball.

Second, I'd recommend opening an issue in the chameleon repository, I don't believe this is an issue with Pyramid.

[digitalresistor]

https://github.com/malthe/chameleon/issues

[castilma]

I reported it there. malthe/chameleon#259

strangely the error message is better, when I install pyramid and chameleon from nix...