Fixes #23643 -- Added chained exception details to debug view.

        return lower_bound, pre_context, context_line, post_context

    def get_traceback_frames(self):

        def explicit_or_implicit_cause(exc_value):

            explicit = getattr(exc_value, '__cause__', None)

            implicit = getattr(exc_value, '__context__', None)

            return explicit or implicit

        # Get the exception and all its causes

        exceptions = []

        exc_value = self.exc_value

        while exc_value:

            exceptions.append(exc_value)

            exc_value = explicit_or_implicit_cause(exc_value)

        frames = []

        tb = self.tb

        # No exceptions were supplied to ExceptionReporter

        if not exceptions:

            return frames

        # In case there's just one exception (always in Python 2,

        # sometimes in Python 3), take the traceback from self.tb (Python 2

        # doesn't have a __traceback__ attribute on Exception)

        exc_value = exceptions.pop()

        tb = self.tb if not exceptions else exc_value.__traceback__

        while tb is not None:

            # Support for __traceback_hide__ which is used by a few libraries

            # to hide internal frames.

            )

            if pre_context_lineno is not None:

                frames.append({

                    'exc_cause': explicit_or_implicit_cause(exc_value),

                    'exc_cause_explicit': getattr(exc_value, '__cause__', True),

                    'tb': tb,

                    'type': 'django' if module_name.startswith('django.') else 'user',

                    'filename': filename,

                    'post_context': post_context,

                    'pre_context_lineno': pre_context_lineno + 1,

                })

            # If the traceback for current exception is consumed, try the

            # other exception.

            if not tb.tb_next and exceptions:

                exc_value = exceptions.pop()

                tb = exc_value.__traceback__

            else:

                tb = tb.tb_next

        return frames

  <div id="browserTraceback">

    <ul class="traceback">

      {% for frame in frames %}

        {% ifchanged frame.exc_cause %}{% if frame.exc_cause %}

          <li><h3>

          {% if frame.exc_cause_explicit %}

            The above exception ({{ frame.exc_cause }}) was the direct cause of the following exception:

          {% else %}

            During handling of the above exception ({{ frame.exc_cause }}), another exception occurred:

          {% endif %}

        </h3></li>

        {% endif %}{% endifchanged %}

        <li class="frame {{ frame.type }}">

          <code>{{ frame.filename|escape }}</code> in <code>{{ frame.function|escape }}</code>

   {{ source_line.0 }} : {{ source_line.1 }}

   {% endifequal %}{% endfor %}{% endif %}{% if frames %}

Traceback:

{% for frame in frames %}File "{{ frame.filename }}" in {{ frame.function }}

{% for frame in frames %}

{% ifchanged frame.exc_cause %}

  {% if frame.exc_cause %}

    {% if frame.exc_cause_explicit %}

      The above exception ({{ frame.exc_cause }}) was the direct cause of the following exception:

    {% else %}

      During handling of the above exception ({{ frame.exc_cause }}), another exception occurred:

    {% endif %}

  {% endif %}

{% endifchanged %}

File "{{ frame.filename }}" in {{ frame.function }}

{% if frame.context_line %}  {{ frame.lineno }}. {{ frame.context_line }}{% endif %}

{% endfor %}

{% if exception_type %}Exception Type: {{ exception_type }}{% if request %} at {{ request.path_info }}{% endif %}

  ``status_code`` outside of the constructor will also modify the value of

  ``reason_phrase``.

* The debug view now shows details of chained exceptions on Python 3.

Tests

^^^^^

install-script = scripts/rpm-install.sh

[flake8]

exclude = build,.git,./django/utils/lru_cache.py,./django/utils/six.py,./django/conf/app_template/*,./django/dispatch/weakref_backports.py,./tests/.env,./xmlrunner

exclude = build,.git,./django/utils/lru_cache.py,./django/utils/six.py,./django/conf/app_template/*,./django/dispatch/weakref_backports.py,./tests/.env,./xmlrunner,tests/view_tests/tests/py3_test_debug.py

ignore = E123,E128,E402,E501,W503,E731,W601

max-line-length = 119

"""

Since this file contains Python 3 specific syntax, it's named without a test_

prefix so the test runner won't try to import it. Instead, the test class is

imported in test_debug.py, but only on Python 3.

This filename is also in setup.cfg flake8 exclude since the Python 2 syntax

error (raise ... from ...) can't be silenced using NOQA.

"""

import sys

from django.test import RequestFactory, TestCase

from django.views.debug import ExceptionReporter

class Py3ExceptionReporterTests(TestCase):

    rf = RequestFactory()

    def test_reporting_of_nested_exceptions(self):

        request = self.rf.get('/test_view/')

        try:

            try:

                raise AttributeError('Top level')

            except AttributeError as explicit:

                try:

                    raise ValueError('Second exception') from explicit

                except ValueError:

                    raise IndexError('Final exception')

        except Exception:

            # Custom exception handler, just pass it into ExceptionReporter

            exc_type, exc_value, tb = sys.exc_info()

        explicit_exc = 'The above exception ({0}) was the direct cause of the following exception:'

        implicit_exc = 'During handling of the above exception ({0}), another exception occurred:'

        reporter = ExceptionReporter(request, exc_type, exc_value, tb)

        html = reporter.get_traceback_html()

        self.assertIn(explicit_exc.format("Top level"), html)

        self.assertIn(implicit_exc.format("Second exception"), html)

        text = reporter.get_traceback_text()

        self.assertIn(explicit_exc.format("Top level"), text)

        self.assertIn(implicit_exc.format("Second exception"), text)

    sensitive_kwargs_function_caller, sensitive_method_view, sensitive_view,

)

if six.PY3:

    from .py3_test_debug import Py3ExceptionReporterTests  # NOQA

class CallableSettingWrapperTests(TestCase):

    """ Unittests for CallableSettingWrapper