[refactor] change default dict params

As raised by kali, they can bring some bugs and avoiding it is pretty
easy.

-- Resolves: #8957

3 files changed, 12 insertions, 8 deletions

diff --git a/src/leap/soledad/common/couch/support.py b/src/leap/soledad/common/couch/support.py
index bfc4fef6..98000dc9 100644
--- a/src/leap/soledad/common/couch/support.py
+++ b/src/leap/soledad/common/couch/support.py
@@ -49,13 +49,14 @@ class MultipartWriter(object):
         self._boundary = boundary
         self._build_headers('related', headers)
 
-    def add(self, mimetype, content, headers={}):
+    def add(self, mimetype, content, headers=None):
         """
         Add a part to the multipart stream.
         """
         self.fileobj.write('--')
         self.fileobj.write(self._boundary)
         self.fileobj.write(self.CRLF)
+        headers = headers or {}
         headers['Content-Type'] = mimetype
         self._write_headers(headers)
         if content:
diff --git a/src/leap/soledad/common/l2db/errors.py b/src/leap/soledad/common/l2db/errors.py
index b502fc2d..d42860fe 100644
--- a/src/leap/soledad/common/l2db/errors.py
+++ b/src/leap/soledad/common/l2db/errors.py
@@ -143,10 +143,10 @@ class HTTPError(U1DBError):
 
     wire_description = None
 
-    def __init__(self, status, message=None, headers={}):
+    def __init__(self, status, message=None, headers=None):
         self.status = status
         self.message = message
-        self.headers = headers
+        self.headers = headers or {}
 
     def __str__(self):
         if not self.message:
@@ -160,8 +160,8 @@ class Unavailable(HTTPError):
 
     wire_description = "unavailable"
 
-    def __init__(self, message=None, headers={}):
-        super(Unavailable, self).__init__(503, message, headers)
+    def __init__(self, message=None, headers=None):
+        super(Unavailable, self).__init__(503, message, headers or {})
 
     def __str__(self):
         if not self.message:
diff --git a/src/leap/soledad/common/l2db/remote/http_app.py b/src/leap/soledad/common/l2db/remote/http_app.py
index a4eddb36..2ec8ac1f 100644
--- a/src/leap/soledad/common/l2db/remote/http_app.py
+++ b/src/leap/soledad/common/l2db/remote/http_app.py
@@ -453,11 +453,12 @@ class HTTPResponder(object):
         self.content_type = 'application/json'
         self.content = []
 
-    def start_response(self, status, obj_dic=None, headers={}):
+    def start_response(self, status, obj_dic=None, headers=None):
         """start sending response with optional first json object."""
         if self._started:
             return
         self._started = True
+        headers = headers or {}
         status_text = httplib.responses[status]
         self._write = self._start_response(
             '%d %s' % (status, status_text),
@@ -473,13 +474,15 @@ class HTTPResponder(object):
         """finish sending response."""
         self.sent_response = True
 
-    def send_response_json(self, status=200, headers={}, **kwargs):
+    def send_response_json(self, status=200, headers=None, **kwargs):
         """send and finish response with json object body from keyword args."""
         content = json.dumps(kwargs) + "\r\n"
+        headers = headers or {}
         self.send_response_content(content, headers=headers, status=status)
 
-    def send_response_content(self, content, status=200, headers={}):
+    def send_response_content(self, content, status=200, headers=None):
         """send and finish response with content"""
+        headers = headers or {}
         headers['content-length'] = str(len(content))
         self.start_response(status, headers=headers)
         if self._stream_state == 1: