Enhance regexp about reference before assignment #20

I stumbled upon an unusual NameError and thought I'd
wrote it down for later.

This test will most likely fail with other intepreters.

didyoumean/didyoumean_internal.py

@@ -521,7 +521,7 @@ def suggest_if_file_is_dir(value):
 
 
 NAMEERRORS = {
-    re.UNBOUNDERROR_RE: suggest_name_not_defined,
+    re.VARREFBEFOREASSIGN_RE: suggest_name_not_defined,
     re.NAMENOTDEFINED_RE: suggest_name_not_defined,
 }
 

didyoumean/didyoumean_re.py

@@ -3,8 +3,8 @@
 import re
 
 
-UNBOUNDERROR_RE = r"^local variable '(?P<name>\w+)' " \
-    r"referenced before assignment$"
+VARREFBEFOREASSIGN_RE = r"^(?:local|free) variable '(?P<name>\w+)' " \
+    r"referenced before assignment(?: in enclosing scope)?$"
 NAMENOTDEFINED_RE = r"^(?:global )?name '(?P<name>\w+)' is not defined$"
 ATTRIBUTEERROR_RE = r"^(?:class |type object )?'?([\w\.]+)'? " \
     r"(?:object |instance )?has no attribute '(\w+)'$"

didyoumean/didyoumean_re_tests.py

@@ -24,12 +24,16 @@ def re_matches(self, text, regexp, results):
         self.assertEqual(named_groups, match.groupdict())
 
     def test_unbound_assignment(self):
-        """Test UNBOUNDERROR_RE."""
-        # Python 2.6/2.7/3.2/3.3/3.4/3.5/PyPy/PyPy3
-        msg = "local variable 'some_var' referenced before assignment"
+        """Test VARREFBEFOREASSIGN_RE."""
+        msgs = [
+            # Python 2.6/2.7/3.2/3.3/3.4/3.5/PyPy/PyPy3
+            "local variable 'some_var' referenced before assignment",
+            "free variable 'some_var' referenced before assignment in enclosing scope",
+        ]
         groups = ('some_var',)
         named_groups = {'name': 'some_var'}
-        self.re_matches(msg, re.UNBOUNDERROR_RE, (groups, named_groups))
+        for msg in msgs:
+            self.re_matches(msg, re.VARREFBEFOREASSIGN_RE, (groups, named_groups))
 
     def test_name_not_defined(self):
         """Test NAMENOTDEFINED_RE."""

didyoumean/didyoumean_sugg_tests.py

@@ -137,9 +137,10 @@ def get_exception(code):
 
 # NameError for NameErrorTests
 NAMEERROR = (NameError, re.NAMENOTDEFINED_RE)
+NAMEERRORBEFOREREF = (NameError, re.VARREFBEFOREASSIGN_RE)
 UNKNOWN_NAMEERROR = (NameError, None)
 # UnboundLocalError for UnboundLocalErrorTests
-UNBOUNDLOCAL = (UnboundLocalError, re.UNBOUNDERROR_RE)
+UNBOUNDLOCAL = (UnboundLocalError, re.VARREFBEFOREASSIGN_RE)
 UNKNOWN_UNBOUNDLOCAL = (UnboundLocalError, None)
 # TypeError for TypeErrorTests
 NBARGERROR = (TypeError, re.NB_ARG_RE)
@@ -378,6 +379,11 @@ def test_no_sugg(self):
         """No suggestion."""
         self.throws('a = ldkjhfnvdlkjhvgfdhgf', NAMEERROR)
 
+    def test_free_var_before_assignment(self):
+        """No suggestion but different error message."""
+        code = 'def f():\n\tdef g():\n\t\treturn free_var\n\tg()\n\tfree_var = 0\nf()'
+        self.throws(code, NAMEERRORBEFOREREF)
+
     # For added/removed names, following functions with one name
     # per functions were added in the early stages of the project.
     # In the future, I'd like to have them replaced by something