Merge pull request #2806 from jorgecarleitao/issue22826

Fixed #22826 -- Improved internal usage of Query.setup_joins.

django/db/models/sql/compiler.py

@@ -96,7 +96,7 @@ class SQLCompiler(object):
         # However we do not want to get rid of stuff done in pre_sql_setup(),
         # as the pre_sql_setup will modify query state in a way that forbids
         # another run of it.
-        self.refcounts_before = self.query.alias_refcount.copy()
+        refcounts_before = self.query.alias_refcount.copy()
         out_cols, s_params = self.get_columns(with_col_aliases)
         ordering, o_params, ordering_group_by = self.get_ordering()
 
@@ -169,7 +169,7 @@ class SQLCompiler(object):
             result.append(self.connection.ops.for_update_sql(nowait=nowait))
 
         # Finally do cleanup - get rid of the joins we created above.
-        self.query.reset_refcounts(self.refcounts_before)
+        self.query.reset_refcounts(refcounts_before)
 
         return ' '.join(result), tuple(params)
 
@@ -546,7 +546,7 @@ class SQLCompiler(object):
                 result.append('%s%s%s' % (connector, qn(name), alias_str))
             first = False
         for t in self.query.extra_tables:
-            alias, unused = self.query.table_alias(t)
+            alias, _ = self.query.table_alias(t)
             # Only add the alias if it's not already present (the table_alias()
             # calls increments the refcount, so an alias refcount of one means
             # this is the only reference.

django/db/models/sql/expressions.py

@@ -57,9 +57,9 @@ class SQLEvaluator(object):
             self.cols.append((node, query.aggregate_select[node.name]))
         else:
             try:
-                field, sources, opts, join_list, path = query.setup_joins(
-                    field_list, query.get_meta(),
-                    query.get_initial_alias(), self.reuse)
+                _, sources, _, join_list, path = query.setup_joins(
+                    field_list, query.get_meta(), query.get_initial_alias(),
+                    can_reuse=self.reuse)
                 self._used_joins = join_list
                 targets, _, join_list = query.trim_joins(sources, join_list, path)
                 if self.reuse is not None:

django/db/models/sql/query.py

@@ -664,16 +664,16 @@ class Query(object):
         If 'create' is true, a new alias is always created. Otherwise, the
         most recently created alias for the table (if one exists) is reused.
         """
-        current = self.table_map.get(table_name)
-        if not create and current:
-            alias = current[0]
+        alias_list = self.table_map.get(table_name)
+        if not create and alias_list:
+            alias = alias_list[0]
             self.alias_refcount[alias] += 1
             return alias, False
 
         # Create a new alias for this table.
-        if current:
+        if alias_list:
             alias = '%s%d' % (self.alias_prefix, len(self.alias_map) + 1)
-            current.append(alias)
+            alias_list.append(alias)
         else:
             # The first occurrence of a table uses the table name directly.
             alias = table_name
@@ -900,7 +900,7 @@ class Query(object):
             return alias
 
         # No reuse is possible, so we need a new alias.
-        alias, _ = self.table_alias(table, True)
+        alias, _ = self.table_alias(table, create=True)
         if not lhs:
             # Not all tables need to be joined to anything. No join type
             # means the later columns are ignored.
@@ -1008,7 +1008,7 @@ class Query(object):
 
             # Join promotion note - we must not remove any rows here, so use
             # outer join if there isn't any existing join.
-            field, sources, opts, join_list, path = self.setup_joins(
+            _, sources, opts, join_list, path = self.setup_joins(
                 field_list, opts, self.get_initial_alias())
 
             # Process the join chain to see if it can be trimmed
@@ -1158,7 +1158,7 @@ class Query(object):
 
         try:
             field, sources, opts, join_list, path = self.setup_joins(
-                parts, opts, alias, can_reuse, allow_many)
+                parts, opts, alias, can_reuse=can_reuse, allow_many=allow_many)
             # split_exclude() needs to know which joins were generated for the
             # lookup parts
             self._lookup_joins = join_list
@@ -1605,9 +1605,8 @@ class Query(object):
             for name in field_names:
                 # Join promotion note - we must not remove any rows here, so
                 # if there is no existing joins, use outer join.
-                field, targets, u2, joins, path = self.setup_joins(
-                    name.split(LOOKUP_SEP), opts, alias, can_reuse=None,
-                    allow_many=allow_m2m)
+                _, targets, _, joins, path = self.setup_joins(
+                    name.split(LOOKUP_SEP), opts, alias, allow_many=allow_m2m)
                 targets, final_alias, joins = self.trim_joins(targets, joins, path)
                 for target in targets:
                     self.select.append(SelectInfo((final_alias, target.column), target))

django/db/models/sql/subqueries.py

@@ -215,7 +215,7 @@ class DateQuery(Query):
         Converts the query into an extraction query.
         """
         try:
-            result = self.setup_joins(
+            field, _, _, joins, _ = self.setup_joins(
                 field_name.split(LOOKUP_SEP),
                 self.get_meta(),
                 self.get_initial_alias(),
@@ -224,9 +224,8 @@ class DateQuery(Query):
             raise FieldDoesNotExist("%s has no field named '%s'" % (
                 self.get_meta().object_name, field_name
             ))
-        field = result[0]
         self._check_field(field)                # overridden in DateTimeQuery
-        alias = result[3][-1]
+        alias = joins[-1]
         select = self._get_select((alias, field.column), lookup_type)
         self.clear_select_clause()
         self.select = [SelectInfo(select, None)]