From e93aad6043f870d04648e7e0af983248ec60c9ef Mon Sep 17 00:00:00 2001
From: Ian Cordasco <graffatcolmingov@gmail.com>
Date: Fri, 29 Jul 2016 17:18:47 -0500
Subject: [PATCH] Open our output file in append mode always

This avoid overwriting portions of our log output when using Flake8
in verbose mode.

Closes #193
---
 docs/source/release-notes/3.0.3.rst | 10 ++++++++--
 src/flake8/formatting/base.py       |  2 +-
 tests/unit/test_base_formatter.py   |  2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/docs/source/release-notes/3.0.3.rst b/docs/source/release-notes/3.0.3.rst
index 17a13b1..92252ac 100644
--- a/docs/source/release-notes/3.0.3.rst
+++ b/docs/source/release-notes/3.0.3.rst
@@ -16,12 +16,18 @@
   not updated for the current version of flake8. This is nicer than raising a
   `PicklingError` about failing to pickle a module (See also `GitLab#164`_)
 
+- Always open our output file in append mode so we do not overwrite log
+  messages. (See also `GitLab#193`_)
+
+
 .. links
+.. _GitLab#164:
+    https://gitlab.com/pycqa/flake8/issues/164
 .. _GitLab#178:
     https://gitlab.com/pycqa/flake8/issues/178
+.. _GitLab#193:
+    https://gitlab.com/pycqa/flake8/issues/193
 .. _GitLab#195:
     https://gitlab.com/pycqa/flake8/issues/195
 .. _this Python bug report:
     https://bugs.python.org/issue27649
-.. _GitLab#164:
-    https://gitlab.com/pycqa/flake8/issues/164
diff --git a/src/flake8/formatting/base.py b/src/flake8/formatting/base.py
index 336bf50..97c60e1 100644
--- a/src/flake8/formatting/base.py
+++ b/src/flake8/formatting/base.py
@@ -50,7 +50,7 @@ class BaseFormatter(object):
         This defaults to initializing :attr:`output_fd` if :attr:`filename`
         """
         if self.filename:
-            self.output_fd = open(self.filename, 'w')
+            self.output_fd = open(self.filename, 'a')
 
     def handle(self, error):
         """Handle an error reported by Flake8.
diff --git a/tests/unit/test_base_formatter.py b/tests/unit/test_base_formatter.py
index ae5c12a..8a99fa6 100644
--- a/tests/unit/test_base_formatter.py
+++ b/tests/unit/test_base_formatter.py
@@ -25,7 +25,7 @@ def test_start(filename):
     if filename is None:
         assert mock_open.called is False
     else:
-        mock_open.assert_called_once_with(filename, 'w')
+        mock_open.assert_called_once_with(filename, 'a')
 
 
 def test_stop():