Merge pull request #7082 from minrk/warn-collision

Warn about .py/.json collisions in config

IPython/config/application.py

@@ -6,6 +6,7 b''
 
 from __future__ import print_function
 
+import json
 import logging
 import os
 import re
@@ -535,8 +536,17 b' class Application(SingletonConfigurable):'
     def load_config_file(self, filename, path=None):
         """Load config files by filename and path."""
         filename, ext = os.path.splitext(filename)
+        loaded = []
         for config in self._load_config_files(filename, path=path, log=self.log):
+            loaded.append(config)
             self.update_config(config)
+        if len(loaded) > 1:
+            collisions = loaded[0].collisions(loaded[1])
+            if collisions:
+                self.log.warn("Collisions detected in {0}.py and {0}.json config files."
+                              " {0}.json has higher priority: {1}".format(
+                              filename, json.dumps(collisions, indent=2),
+                ))
 
 
     def generate_config_file(self):

IPython/config/loader.py

@@ -193,7 +193,27 b' class Config(dict):'
                     to_update[k] = copy.deepcopy(v)
 
         self.update(to_update)
-
+    
+    def collisions(self, other):
+        """Check for collisions between two config objects.
+        
+        Returns a dict of the form {"Class": {"trait": "collision message"}}`,
+        indicating which values have been ignored.
+        
+        An empty dict indicates no collisions.
+        """
+        collisions = {}
+        for section in self:
+            if section not in other:
+                continue
+            mine = self[section]
+            theirs = other[section]
+            for key in mine:
+                if key in theirs and mine[key] != theirs[key]:
+                    collisions.setdefault(section, {})
+                    collisions[section][key] = "%r ignored, using %r" % (mine[key], theirs[key])
+        return collisions
+    
     def __contains__(self, key):
         # allow nested contains of the form `"Section.key" in config`
         if '.' in key:
@@ -565,7 +585,7 b' class KeyValueConfigLoader(CommandLineConfigLoader):'
 
 
     def _decode_argv(self, argv, enc=None):
-        """decode argv if bytes, using stin.encoding, falling back on default enc"""
+        """decode argv if bytes, using stdin.encoding, falling back on default enc"""
         uargv = []
         if enc is None:
             enc = DEFAULT_ENCODING

IPython/config/tests/test_loader.py

@@ -1,28 +1,12 b''
 # encoding: utf-8
-"""
-Tests for IPython.config.loader
-
-Authors:
-
-* Brian Granger
-* Fernando Perez (design help)
-"""
+"""Tests for IPython.config.loader"""
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008 The IPython Development Team
-#
-#  Distributed under the terms of the BSD License.  The full license is in
-#  the file COPYING, distributed as part of this software.
-#-----------------------------------------------------------------------------
-
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 
 import os
 import pickle
 import sys
-import json
 
 from tempfile import mkstemp
 from unittest import TestCase
@@ -43,10 +27,6 b' from IPython.config.loader import ('
     ConfigError,
 )
 
-#-----------------------------------------------------------------------------
-# Actual tests
-#-----------------------------------------------------------------------------
-
 
 pyfile = """
 c = get_config()
@@ -117,6 +97,34 b' class TestFileCL(TestCase):'
         cl = JSONFileConfigLoader(fname, log=log)
         config = cl.load_config()
         self._check_conf(config)
+    
+    def test_collision(self):
+        a = Config()
+        b = Config()
+        self.assertEqual(a.collisions(b), {})
+        a.A.trait1 = 1
+        b.A.trait2 = 2
+        self.assertEqual(a.collisions(b), {})
+        b.A.trait1 = 1
+        self.assertEqual(a.collisions(b), {})
+        b.A.trait1 = 0
+        self.assertEqual(a.collisions(b), {
+            'A': {
+                'trait1': "1 ignored, using 0",
+            }
+        })
+        self.assertEqual(b.collisions(a), {
+            'A': {
+                'trait1': "0 ignored, using 1",
+            }
+        })
+        a.A.trait2 = 3
+        self.assertEqual(b.collisions(a), {
+            'A': {
+                'trait1': "0 ignored, using 1",
+                'trait2': "2 ignored, using 3",
+            }
+        })
 
     def test_v2raise(self):
         fd, fname = mkstemp('.json')