#12992: New template loaders lose debug information
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Reporter: kmtracey | Owner: nobody
Status: new | Milestone: 1.2
Component: Template system | Version: 1.1
Keywords: | Stage: Unreviewed
Has_patch: 0 |
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For a !TemplateSyntaxErorr, if you have the new-style template loaders in
`settings.py`:
{{{
#!python
TEMPLATE_LOADERS = (
'django.template.loaders.filesystem.Loader',
'django.template.loaders.app_directories.Loader',
# 'django.template.loaders.eggs.Loader',
)
}}}
The `Template error` section of the debug page doesn't report the name of
the template file where the problem occurred. Instead it reports `In
template <unknown source>, error at line <whatever>`. One problem is
the angle brackets aren't displayed properly but the real problem is that
the source file name is "unknown".
Problem is due to the new-style loader's returning already-compiled
templates (from
http://code.djangoproject.com/browser/django/trunk/django/template/loader.py#L36):
{{{
#!python
def __call__(self, template_name, template_dirs=None):
return self.load_template(template_name, template_dirs)
def load_template(self, template_name, template_dirs=None):
source, origin = self.load_template_source(template_name,
template_dirs)
template = get_template_from_string(source, name=template_name)
return template, origin
}}}
The old loaders return the `source, origin` as originally returned by
`load_template_source`, and the template source is compiled into a
`<django.template.Template>` when `get_template` finds what it got doesn't
have a `render` (from
http://code.djangoproject.com/browser/django/trunk/django/template/loader.py#L139):
{{{
#!python
def get_template(template_name):
"""
Returns a compiled Template object for the given template name,
handling template inheritance recursively.
"""
template, origin = find_template(template_name)
if not hasattr(template, 'render'):
# template needs to be compiled
template = get_template_from_string(template, origin,
template_name)
return template
}}}
That call to `get_template_from_string` includes the origin, which is what
is needed to report the file name on the debug page.
Note `origin` in this bit of code is different from the `origin` returned
by `load_template_source` above. That part of the `load_template_source`
return value is called `display_name` in other parts of the code and is
one of four args passed to `make_origin` to produce the `origin` passed in
to `get_template_from_string` in the working path. So we cannot simply
change the new-style loader code to pass the thing it calls `origin` to
`get_template_from_string`. Nor does attempting to call `make_origin` with
likely-seeming args in the new-style loader code work, possibly because I
don't really have a clue what those args are supposed to all be. What does
work is:
{{{
#!python
def __call__(self, template_name, template_dirs=None):
return self.load_template_source(template_name, template_dirs)
}}}
But I gather based on the doc here:
http://docs.djangoproject.com/en/dev/ref/templates/api/#using-an-
alternative-template-language that loaders are supposed to have a
`load_template` method that returns a pre-compiled template so it would
probably be better for someone with a clue in this area to figure out how
to get the origin information properly attached to the already-compiled
template returned by the new-style loaders.
--
Ticket URL: <http://code.djangoproject.com/ticket/12992>
Django <http://code.djangoproject.com/>
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