There is an error, when a source file with backslash-r returns is interpreted by the Python error report page.

[petrvanblokland]

There is an error, when a source file with backslash-r returns is interpreted by the Python error report page.

Due to a hard split on backslah-n, the lineno is out of range.
Also it is not clear what the name of the file is where this goes wrong.
Adding source = source.replace('\r', '\n') solves the problem, but maybe not structural enough.

Kind regards,
Petr van Blokland
buro@…

 Traceback (most recent call last):

  File "/Library/Python/2.5/site-packages/django/core/servers/basehttp.py", line 279, in run
    self.result = application(self.environ, self.start_response)

  File "/Library/Python/2.5/site-packages/django/core/servers/basehttp.py", line 651, in __call__
    return self.application(environ, start_response)

  File "/Library/Python/2.5/site-packages/django/core/handlers/wsgi.py", line 241, in __call__
    response = self.get_response(request)

  File "/Library/Python/2.5/site-packages/django/core/handlers/base.py", line 137, in get_response
    return self.handle_uncaught_exception(request, resolver, exc_info)

  File "/Library/Python/2.5/site-packages/django/core/handlers/base.py", line 157, in handle_uncaught_exception
    return debug.technical_500_response(request, *exc_info)

  File "/Library/Python/2.5/site-packages/django/views/debug.py", line 58, in technical_500_response
    html = reporter.get_traceback_html()

  File "/Library/Python/2.5/site-packages/django/views/debug.py", line 109, in get_traceback_html
    frames = self.get_traceback_frames()

  File "/Library/Python/2.5/site-packages/django/views/debug.py", line 228, in get_traceback_frames
    pre_context_lineno, pre_context, context_line, post_context = self._get_lines_from_file(filename, lineno, 7, loader, module_name)

  File "/Library/Python/2.5/site-packages/django/views/debug.py", line 209, in _get_lines_from_file
    context_line = source[lineno].strip('\n')

IndexError: list index out of range

[Karen Tracey]

Fixed formatting. Please use WikiFormatting and the preview button before submitting.

[Natalia Bidart]

Hello!

I'm tying to reproduce this issue but I can't. Can you please add detailed instructions so we can reproduce?

I've confirmed that when opening a file with open(), python will correctly handle the different line terminators according to the platform, so after calling readlines() on a file descriptor returned with open() (using mode 'r'), the lines will only have the '\n' at the end, not the '\r\n'.

So maybe, this bug is caused by the call to 'loader.get_source' (django/views/debug.py(180)), but I can't confirm it without some more context.

[Russell Keith-Magee]

Closing invalid. Reporter hasn't responded to a request for more info. Please reopen if you can provide a test case as requested.

[fredrik.kers@…]

django.views.debug._get_lines_from_file uses readlines to split the lines of a file. This functions does not support the old Macintosh line break (\r) which is a valid line break in python code (​http://docs.python.org/reference/lexical_analysis.html#physical-lines). So when an exception occurs in a file with Macintosh line break, the get_lines_from_file method will get an exception on the line

context_line = source[lineno].strip('\n')

since the source list will only contain one line with alot of '\r'.

This can be fixed by replacing the line

source = f.readlines()

with

source = f.read().splitlines()

[Alex Gaynor]

Closing as needsinfo. In order to accept this bug we need to know how to actually reproduce it, not just a statement of what looks wrong in the code and what to change.

[fredrik.kers@…]

Patch and unittest added

[Aymeric Augustin]

The test case looks valid (even though the style could be improved).

utils.text.normalize_newlines might be handy here.

[Riccardo Attilio Galli]

Updated the patch and refactored the test code

[Steffen Zieger]

This patch is working for the current Django master

[Shai Berger <shai.berger@…>]

In ff881aef536640d712fd2bc53fa1ff98e300adad:

Fixed #13958 -- problem reporting exception from \r-line-ended file

Thanks petrvanblokland for reporting and saz for the patch