Don't report variable errors silenced by django. Fixes #1276

src/ptvsd/_vendored/pydevd/pydevd_plugins/django_debug.py

@@ -358,6 +358,17 @@ def _is_django_variable_does_not_exist_exception_break_context(frame):
         name = None
     return name in ('_resolve_lookup', 'find_template')
 
+
+def _is_ignoring_failures(frame):
+    while frame is not None:
+        if frame.f_code.co_name == 'resolve':
+            ignore_failures = frame.f_locals.get('ignore_failures')
+            if ignore_failures:
+                return True
+        frame = frame.f_back
+
+    return False
+
 #=======================================================================================================================
 # Django Step Commands
 #=======================================================================================================================
@@ -520,15 +531,16 @@ def exception_break(plugin, main_debugger, pydb_frame, frame, args, arg):
 
             elif exception.__name__ == 'VariableDoesNotExist':
                 if _is_django_variable_does_not_exist_exception_break_context(frame):
-                    render_frame = _find_django_render_frame(frame)
-                    if render_frame:
-                        suspend_frame = suspend_django(
-                            main_debugger, thread, DjangoTemplateFrame(render_frame), CMD_ADD_EXCEPTION_BREAK)
-                        if suspend_frame:
-                            add_exception_to_frame(suspend_frame, (exception, value, trace))
-                            thread.additional_info.pydev_message = 'VariableDoesNotExist'
-                            suspend_frame.f_back = frame
-                            frame = suspend_frame
-                            return True, frame
+                    if not getattr(exception, 'silent_variable_failure', False) and not _is_ignoring_failures(frame):
+                        render_frame = _find_django_render_frame(frame)
+                        if render_frame:
+                            suspend_frame = suspend_django(
+                                main_debugger, thread, DjangoTemplateFrame(render_frame), CMD_ADD_EXCEPTION_BREAK)
+                            if suspend_frame:
+                                add_exception_to_frame(suspend_frame, (exception, value, trace))
+                                thread.additional_info.pydev_message = 'VariableDoesNotExist'
+                                suspend_frame.f_back = frame
+                                frame = suspend_frame
+                                return True, frame
 
     return None

src/ptvsd/_vendored/pydevd/tests_python/my_django_proj_17/my_app/templates/my_app/no_var_error.html

@@ -0,0 +1,5 @@
+{% if pat.name %}
+    pat.name={{ pat.name }}
+{% else %}
+    no_pat_name
+{% endif %}

src/ptvsd/_vendored/pydevd/tests_python/my_django_proj_17/my_app/urls.py

@@ -8,4 +8,5 @@
     url(r'^template_error$', views.template_error, name='template_error'),
     url(r'^template_error2$', views.template_error2, name='template_error2'),
     url(r'^inherits$', views.inherits, name='inherits'),
+    url(r'^no_var_error$', views.no_var_error, name='no_var_error'),
 ]

src/ptvsd/_vendored/pydevd/tests_python/my_django_proj_17/my_app/views.py

@@ -65,3 +65,9 @@ def template_error2(request):
     context = {}
     ret = render(request, 'my_app/template_error2.html', context)
     return ret
+
+
+def no_var_error(request):
+    context = {}
+    ret = render(request, 'my_app/no_var_error.html', context)
+    return ret

src/ptvsd/_vendored/pydevd/tests_python/my_django_proj_21/my_app/templates/my_app/no_var_error.html

@@ -0,0 +1,5 @@
+{% if pat.name %}
+    pat.name={{ pat.name }}
+{% else %}
+    no_pat_name
+{% endif %}

src/ptvsd/_vendored/pydevd/tests_python/my_django_proj_21/my_app/urls.py

@@ -8,4 +8,5 @@
     url(r'^template_error2$', views.template_error2, name='template_error2'),
     url(r'^template_error$', views.template_error, name='template_error'),
     url(r'^inherits$', views.inherits, name='inherits'),
+    url(r'^no_var_error$', views.no_var_error, name='no_var_error'),
 ]

src/ptvsd/_vendored/pydevd/tests_python/my_django_proj_21/my_app/views.py

@@ -72,3 +72,9 @@ def inherits(request):
     context = {}
     ret = render(request, 'my_app/inherits.html', context)
     return ret
+
+
+def no_var_error(request):
+    context = {}
+    ret = render(request, 'my_app/no_var_error.html', context)
+    return ret

src/ptvsd/_vendored/pydevd/tests_python/test_debugger.py

@@ -963,6 +963,26 @@ def test_case_django_template_inherits_no_exception(case_setup_django):
         writer.finished_ok = True
 
 
+@pytest.mark.skipif(not TEST_DJANGO, reason='No django available')
+def test_case_django_no_var_error(case_setup_django):
+    with case_setup_django.test_file(EXPECTED_RETURNCODE='any') as writer:
+
+        # Check that it doesn't have issues with inherits + django exception breakpoints.
+        writer.write_add_exception_breakpoint_django()
+
+        writer.write_make_initial_run()
+
+        t = writer.create_request_thread('my_app/no_var_error')
+        time.sleep(5)  # Give django some time to get to startup before requesting the page
+        t.start()
+        contents = t.wait_for_contents()
+
+        contents = contents.replace(' ', '').replace('\r', '').replace('\n', '')
+        assert contents == '''no_pat_name'''
+
+        writer.finished_ok = True
+
+
 @pytest.mark.skipif(not TEST_DJANGO, reason='No django available')
 @pytest.mark.parametrize("jmc", [False, True])
 def test_case_django_no_attribute_exception_breakpoint(case_setup_django, jmc):