Promote a couple of warnings to errors.

These warnings were promoted since they could uncover
potential bugs in the code and since most people are using `pylint -E` anyway,
it's good to have them as errors. These warnings are: assignment-from-none,
unbalanced-tuple-unpacking, unpacking-non-sequence, non-iterator-returned.
Closes issue #388.

7 files changed, 26 insertions, 19 deletions

diff --git a/ChangeLog b/ChangeLog
index 6909dda..cfc015d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,10 @@ ChangeLog for Pylint
       exception handler which handles an exception type that was handled
       before. Closes issue #485.
 
+    * A couple of warnings got promoted to errors, since they could uncover
+      potential bugs in the code. These warnings are: assignment-from-none,
+      unbalanced-tuple-unpacking, unpacking-non-sequence, non-iterator-returned.
+      Closes issue #388.
 
 2015-03-14 -- 1.4.3
 
diff --git a/pylint/checkers/classes.py b/pylint/checkers/classes.py
index 87e3bcf..fe6d26d 100644
--- a/pylint/checkers/classes.py
+++ b/pylint/checkers/classes.py
@@ -210,10 +210,11 @@ MSGS = {
               'non-parent-init-called',
               'Used when an __init__ method is called on a class which is not '
               'in the direct ancestors for the analysed class.'),
-    'W0234': ('__iter__ returns non-iterator',
+    'E0234': ('__iter__ returns non-iterator',
               'non-iterator-returned',
               'Used when an __iter__ method returns something which is not an '
-               'iterable (i.e. has no `%s` method)' % NEXT_METHOD),
+              'iterable (i.e. has no `%s` method)' % NEXT_METHOD,
+              {'old_names': [('W0234', 'non-iterator-returned')]}),
     'E0235': ('__exit__ must accept 3 arguments: type, value, traceback',
               'bad-context-manager',
               'Used when the __exit__ special method, belonging to a '
diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index 9f074ae..71cb673 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -42,11 +42,6 @@ MSGS = {
               'assignment-from-no-return',
               'Used when an assignment is done on a function call but the \
               inferred function doesn\'t return anything.'),
-    'W1111': ('Assigning to function call which only returns None',
-              'assignment-from-none',
-              'Used when an assignment is done on a function call but the \
-              inferred function returns nothing but None.'),
-
     'E1120': ('No value for argument %s in %s call',
               'no-value-for-parameter',
               'Used when a function call passes too few arguments.'),
@@ -77,6 +72,11 @@ MSGS = {
               'invalid-slice-index',
               'Used when a slice index is not an integer, None, or an object \
                with an __index__ method.'),
+    'E1128': ('Assigning to function call which only returns None',
+              'assignment-from-none',
+              'Used when an assignment is done on a function call but the '
+              'inferred function returns nothing but None.',
+              {'old_names': [('W1111', 'assignment-from-none')]}),
     }
 
 # builtin sequence types in Python 2 and 3.
diff --git a/pylint/checkers/variables.py b/pylint/checkers/variables.py
index 8f6f957..1841846 100644
--- a/pylint/checkers/variables.py
+++ b/pylint/checkers/variables.py
@@ -255,16 +255,18 @@ MSGS = {
               a list comprehension or a generator expression) is used outside \
               the loop.'),
 
-    'W0632': ('Possible unbalanced tuple unpacking with '
+    'E0632': ('Possible unbalanced tuple unpacking with '
               'sequence%s: '
               'left side has %d label(s), right side has %d value(s)',
               'unbalanced-tuple-unpacking',
-              'Used when there is an unbalanced tuple unpacking in assignment'),
+              'Used when there is an unbalanced tuple unpacking in assignment',
+              {'old_names': [('W0632', 'unbalanced-tuple-unpacking')]}),
 
-    'W0633': ('Attempting to unpack a non-sequence%s',
+    'E0633': ('Attempting to unpack a non-sequence%s',
               'unpacking-non-sequence',
               'Used when something which is not '
-              'a sequence is used in an unpack assignment'),
+              'a sequence is used in an unpack assignment',
+              {'old_names': [('W0633', 'unpacking-non-sequence')]}),
 
     'W0640': ('Cell variable %s defined in loop',
               'cell-var-from-loop',
diff --git a/pylint/test/messages/func_non_iterator_returned_py30.txt b/pylint/test/messages/func_non_iterator_returned_py30.txt
index b41b14b..c956ae7 100644
--- a/pylint/test/messages/func_non_iterator_returned_py30.txt
+++ b/pylint/test/messages/func_non_iterator_returned_py30.txt
@@ -1,3 +1,3 @@
-W: 39:FirstBadIterator.__iter__: __iter__ returns non-iterator
-W: 45:SecondBadIterator.__iter__: __iter__ returns non-iterator
-W: 51:ThirdBadIterator.__iter__: __iter__ returns non-iterator
\ No newline at end of file
+E: 39:FirstBadIterator.__iter__: __iter__ returns non-iterator
+E: 45:SecondBadIterator.__iter__: __iter__ returns non-iterator
+E: 51:ThirdBadIterator.__iter__: __iter__ returns non-iterator
\ No newline at end of file
diff --git a/pylint/test/messages/func_non_iterator_returned_py_30.txt b/pylint/test/messages/func_non_iterator_returned_py_30.txt
index b41b14b..c956ae7 100644
--- a/pylint/test/messages/func_non_iterator_returned_py_30.txt
+++ b/pylint/test/messages/func_non_iterator_returned_py_30.txt
@@ -1,3 +1,3 @@
-W: 39:FirstBadIterator.__iter__: __iter__ returns non-iterator
-W: 45:SecondBadIterator.__iter__: __iter__ returns non-iterator
-W: 51:ThirdBadIterator.__iter__: __iter__ returns non-iterator
\ No newline at end of file
+E: 39:FirstBadIterator.__iter__: __iter__ returns non-iterator
+E: 45:SecondBadIterator.__iter__: __iter__ returns non-iterator
+E: 51:ThirdBadIterator.__iter__: __iter__ returns non-iterator
\ No newline at end of file
diff --git a/pylint/test/messages/func_typecheck_callfunc_assigment.txt b/pylint/test/messages/func_typecheck_callfunc_assigment.txt
index 1d84510..e1d0564 100644
--- a/pylint/test/messages/func_typecheck_callfunc_assigment.txt
+++ b/pylint/test/messages/func_typecheck_callfunc_assigment.txt
@@ -1,3 +1,3 @@
 E: 20: Assigning to function call which doesn't return
-W: 28: Assigning to function call which only returns None
-W: 35: Assigning to function call which only returns None
+E: 28: Assigning to function call which only returns None
+E: 35: Assigning to function call which only returns None