Django highlights incorrect lines for template errors

[michaelvantellingen@…]

This issue is bugging me for a while now and after searching for existing tickets (and finding none) i've decided to create a ticket for it.

Basically Django highlights the wrong lines when a template error occurs. Sometimes it even highlights a seemingly random line in the parent template (when an error occurs in the template which is included).

I'll attach a screenshot with an example.

[michaelvantellingen@…]

Example

[michaelvantellingen@…]

Pullrequest at ​https://github.com/django/django/pull/721

[Aymeric Augustin]

The patch looks quite good, but it needs a bit of polish.

First, I suggest to redo the PR against master.

You must support Python 2.6+ and 3.2+. Specifically, use the syntax except TemplateSyntaxError as e: to catch exceptions.

To test an exception, there's ​assertRaisesRegexp. Since it was renamed in Python 3, you must use this slightly contrived syntax:

from django.utils import six

with six.assertRaisesRegex(self, TemplateSyntaxError, ...):
    # raise exception here

Finally, make sure the code is clean — there a suprious print statement and a stray newline in a docstring.

Thanks!

[michaelvantellingen@…]

Thanks for the feedback! Here is a new PR against master. Tested it with python 2.6, 2.7 and 3.2:

​https://github.com/django/django/pull/723

[Aymeric Augustin <aymeric.augustin@…>]

In 138de533ff677b470a1e7b4b6ff084a5b7a7444b:

Fixed #19819 - Improved template filter errors handling.

Wrap the Parser.compile_filter method call with a try/except and call the
newly added Parser.compile_filter_error(). Overwrite this method in the
DebugParser to throw the correct error.

Since this error was otherwise catched by the compile_function try/except
block the debugger highlighted the wrong line.