To avoid an unfortunately common user-error, rename QuerySet.as_sql().

This was never a public API method, so this is backwards compatible, unless
you're poking at the internals. Refs #10352.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9928 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/__init__.py

@@ -193,12 +193,15 @@ class Field(object):
 
     def get_db_prep_lookup(self, lookup_type, value):
         "Returns field's value prepared for database lookup."
-        if hasattr(value, 'as_sql'):
+        if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):
             # If the value has a relabel_aliases method, it will need to
             # be invoked before the final SQL is evaluated
             if hasattr(value, 'relabel_aliases'):
                 return value
-            sql, params = value.as_sql()
+            try:
+                sql, params = value.as_sql()
+            except AttributeError:
+                sql, params = value._as_sql()
             return QueryWrapper(('(%s)' % sql), params)
 
         if lookup_type in ('regex', 'iregex', 'month', 'day', 'week_day', 'search'):

django/db/models/fields/related.py

@@ -140,12 +140,15 @@ class RelatedField(object):
                     v = v[0]
             return v
 
-        if hasattr(value, 'as_sql'):
+        if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):
             # If the value has a relabel_aliases method, it will need to
             # be invoked before the final SQL is evaluated
             if hasattr(value, 'relabel_aliases'):
                 return value
-            sql, params = value.as_sql()
+            try:
+                sql, params = value.as_sql()
+            except AttributeError:
+                sql, params = value._as_sql()
             return QueryWrapper(('(%s)' % sql), params)
 
         # FIXME: lt and gt are explicitally allowed to make

django/db/models/query.py

@@ -703,12 +703,9 @@ class QuerySet(object):
             self.query.add_fields(field_names, False)
             self.query.set_group_by()
 
-    def as_sql(self):
+    def _as_sql(self):
         """
         Returns the internal query's SQL and parameters (as a tuple).
-
-        This is a private (internal) method. The name is chosen to provide
-        uniformity with other interfaces (in particular, the Query class).
         """
         obj = self.values("pk")
         return obj.query.as_nested_sql()
@@ -812,7 +809,7 @@ class ValuesQuerySet(QuerySet):
 
         super(ValuesQuerySet, self)._setup_aggregate_query(aggregates)
 
-    def as_sql(self):
+    def _as_sql(self):
         """
         For ValueQuerySet (and subclasses like ValuesListQuerySet), they can
         only be used as nested queries if they're already set up to select only