Fixed #19190 -- Refactored Query select clause attributes

The Query.select and Query.select_fields were collapsed into one list
because the attributes had to be always in sync. Now that they are in
one attribute it is impossible to edit them out of sync.

Similar collapse was done for Query.related_select_cols and
Query.related_select_fields.

5 files changed, 61 insertions, 65 deletions

diff --git a/django/contrib/gis/db/models/sql/compiler.py b/django/contrib/gis/db/models/sql/compiler.py
index cf6a8ad047..0dcf50d32a 100644
--- a/django/contrib/gis/db/models/sql/compiler.py
+++ b/django/contrib/gis/db/models/sql/compiler.py
@@ -39,7 +39,7 @@ class GeoSQLCompiler(compiler.SQLCompiler):
         if self.query.select:
             only_load = self.deferred_to_columns()
             # This loop customized for GeoQuery.
-            for col, field in zip(self.query.select, self.query.select_fields):
+            for col, field in self.query.select:
                 if isinstance(col, (list, tuple)):
                     alias, column = col
                     table = self.query.alias_map[alias].table_name
@@ -85,7 +85,7 @@ class GeoSQLCompiler(compiler.SQLCompiler):
         ])
 
         # This loop customized for GeoQuery.
-        for (table, col), field in zip(self.query.related_select_cols, self.query.related_select_fields):
+        for (table, col), field in self.query.related_select_cols:
             r = self.get_field_select(field, table, col)
             if with_aliases and col in col_aliases:
                 c_alias = 'Col%d' % len(col_aliases)
diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index b9095e503a..7461f5f31d 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -6,7 +6,7 @@ from django.db.backends.util import truncate_name
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.query_utils import select_related_descend
 from django.db.models.sql.constants import (SINGLE, MULTI, ORDER_DIR,
-        GET_ITERATOR_CHUNK_SIZE)
+        GET_ITERATOR_CHUNK_SIZE, SelectInfo)
 from django.db.models.sql.datastructures import EmptyResultSet
 from django.db.models.sql.expressions import SQLEvaluator
 from django.db.models.sql.query import get_order_dir, Query
@@ -188,7 +188,7 @@ class SQLCompiler(object):
             col_aliases = set()
         if self.query.select:
             only_load = self.deferred_to_columns()
-            for col in self.query.select:
+            for col, _ in self.query.select:
                 if isinstance(col, (list, tuple)):
                     alias, column = col
                     table = self.query.alias_map[alias].table_name
@@ -233,7 +233,7 @@ class SQLCompiler(object):
             for alias, aggregate in self.query.aggregate_select.items()
         ])
 
-        for table, col in self.query.related_select_cols:
+        for (table, col), _ in self.query.related_select_cols:
             r = '%s.%s' % (qn(table), qn(col))
             if with_aliases and col in col_aliases:
                 c_alias = 'Col%d' % len(col_aliases)
@@ -557,8 +557,9 @@ class SQLCompiler(object):
             for extra_select, extra_params in six.itervalues(self.query.extra_select):
                 extra_selects.append(extra_select)
                 params.extend(extra_params)
-            cols = (group_by + self.query.select +
-                self.query.related_select_cols + extra_selects)
+            select_cols = [s.col for s in self.query.select]
+            related_select_cols = [s.col for s in self.query.related_select_cols]
+            cols = (group_by + select_cols + related_select_cols + extra_selects)
             seen = set()
             for col in cols:
                 if col in seen:
@@ -589,7 +590,6 @@ class SQLCompiler(object):
             opts = self.query.get_meta()
             root_alias = self.query.get_initial_alias()
             self.query.related_select_cols = []
-            self.query.related_select_fields = []
         if not used:
             used = set()
         if dupe_set is None:
@@ -664,8 +664,8 @@ class SQLCompiler(object):
             used.add(alias)
             columns, aliases = self.get_default_columns(start_alias=alias,
                     opts=f.rel.to._meta, as_pairs=True)
-            self.query.related_select_cols.extend(columns)
-            self.query.related_select_fields.extend(f.rel.to._meta.fields)
+            self.query.related_select_cols.extend(
+                SelectInfo(col, field) for col, field in zip(columns, f.rel.to._meta.fields))
             if restricted:
                 next = requested.get(f.name, {})
             else:
@@ -734,8 +734,8 @@ class SQLCompiler(object):
                 used.add(alias)
                 columns, aliases = self.get_default_columns(start_alias=alias,
                     opts=model._meta, as_pairs=True, local_only=True)
-                self.query.related_select_cols.extend(columns)
-                self.query.related_select_fields.extend(model._meta.fields)
+                self.query.related_select_cols.extend(
+                    SelectInfo(col, field) for col, field in zip(columns, model._meta.fields))
 
                 next = requested.get(f.related_query_name(), {})
                 # Use True here because we are looking at the _reverse_ side of
@@ -772,7 +772,7 @@ class SQLCompiler(object):
                 if resolve_columns:
                     if fields is None:
                         # We only set this up here because
-                        # related_select_fields isn't populated until
+                        # related_select_cols isn't populated until
                         # execute_sql() has been called.
 
                         # We also include types of fields of related models that
@@ -782,11 +782,11 @@ class SQLCompiler(object):
 
                         # This code duplicates the logic for the order of fields
                         # found in get_columns(). It would be nice to clean this up.
-                        if self.query.select_fields:
-                            fields = self.query.select_fields
+                        if self.query.select:
+                            fields = [f.field for f in self.query.select]
                         else:
                             fields = self.query.model._meta.fields
-                        fields = fields + self.query.related_select_fields
+                        fields = fields + [f.field for f in self.query.related_select_cols]
 
                         # If the field was deferred, exclude it from being passed
                         # into `resolve_columns` because it wasn't selected.
diff --git a/django/db/models/sql/constants.py b/django/db/models/sql/constants.py
index f750310624..7e34047e1d 100644
--- a/django/db/models/sql/constants.py
+++ b/django/db/models/sql/constants.py
@@ -25,6 +25,9 @@ JoinInfo = namedtuple('JoinInfo',
                       'table_name rhs_alias join_type lhs_alias '
                       'lhs_join_col rhs_join_col nullable')
 
+# Pairs of column clauses to select, and (possibly None) field for the clause.
+SelectInfo = namedtuple('SelectInfo', 'col field')
+
 # How many results to expect from a cursor.execute call
 MULTI = 'multi'
 SINGLE = 'single'
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index cef01c48ab..de7e5904a3 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -20,7 +20,7 @@ from django.db.models.expressions import ExpressionNode
 from django.db.models.fields import FieldDoesNotExist
 from django.db.models.sql import aggregates as base_aggregates_module
 from django.db.models.sql.constants import (QUERY_TERMS, ORDER_DIR, SINGLE,
-        ORDER_PATTERN, JoinInfo)
+        ORDER_PATTERN, JoinInfo, SelectInfo)
 from django.db.models.sql.datastructures import EmptyResultSet, Empty, MultiJoin
 from django.db.models.sql.expressions import SQLEvaluator
 from django.db.models.sql.where import (WhereNode, Constraint, EverythingNode,
@@ -115,17 +115,20 @@ class Query(object):
         self.default_ordering = True
         self.standard_ordering = True
         self.ordering_aliases = []
-        self.related_select_fields = []
         self.dupe_avoidance = {}
         self.used_aliases = set()
         self.filter_is_sticky = False
         self.included_inherited_models = {}
 
-        # SQL-related attributes
+        # SQL-related attributes  
+        # Select and related select clauses as SelectInfo instances.
+        # The select is used for cases where we want to set up the select
+        # clause to contain other than default fields (values(), annotate(),
+        # subqueries...)
         self.select = []
-        # For each to-be-selected field in self.select there must be a
-        # corresponding entry in self.select - git seems to need this.
-        self.select_fields = []
+        # The related_select_cols is used for columns needed for
+        # select_related - this is populated in compile stage.
+        self.related_select_cols = []
         self.tables = []    # Aliases in the order they are created.
         self.where = where()
         self.where_class = where
@@ -138,7 +141,6 @@ class Query(object):
         self.select_for_update = False
         self.select_for_update_nowait = False
         self.select_related = False
-        self.related_select_cols = []
 
         # SQL aggregate-related attributes
         self.aggregates = SortedDict() # Maps alias -> SQL aggregate function
@@ -191,15 +193,14 @@ class Query(object):
         Pickling support.
         """
         obj_dict = self.__dict__.copy()
-        obj_dict['related_select_fields'] = []
         obj_dict['related_select_cols'] = []
 
         # Fields can't be pickled, so if a field list has been
         # specified, we pickle the list of field names instead.
         # None is also a possible value; that can pass as-is
-        obj_dict['select_fields'] = [
-            f is not None and f.name or None
-            for f in obj_dict['select_fields']
+        obj_dict['select'] = [
+            (s.col, s.field is not None and s.field.name or None)
+            for s in obj_dict['select']
         ]
         return obj_dict
 
@@ -209,9 +210,9 @@ class Query(object):
         """
         # Rebuild list of field instances
         opts = obj_dict['model']._meta
-        obj_dict['select_fields'] = [
-            name is not None and opts.get_field(name) or None
-            for name in obj_dict['select_fields']
+        obj_dict['select'] = [
+            SelectInfo(tpl[0], tpl[1] is not None and opts.get_field(tpl[1]) or None)
+            for tpl in obj_dict['select']
         ]
 
         self.__dict__.update(obj_dict)
@@ -256,10 +257,9 @@ class Query(object):
         obj.standard_ordering = self.standard_ordering
         obj.included_inherited_models = self.included_inherited_models.copy()
         obj.ordering_aliases = []
-        obj.select_fields = self.select_fields[:]
-        obj.related_select_fields = self.related_select_fields[:]
         obj.dupe_avoidance = self.dupe_avoidance.copy()
         obj.select = self.select[:]
+        obj.related_select_cols = []
         obj.tables = self.tables[:]
         obj.where = copy.deepcopy(self.where, memo=memo)
         obj.where_class = self.where_class
@@ -275,7 +275,6 @@ class Query(object):
         obj.select_for_update = self.select_for_update
         obj.select_for_update_nowait = self.select_for_update_nowait
         obj.select_related = self.select_related
-        obj.related_select_cols = []
         obj.aggregates = copy.deepcopy(self.aggregates, memo=memo)
         if self.aggregate_select_mask is None:
             obj.aggregate_select_mask = None
@@ -384,7 +383,6 @@ class Query(object):
         query.select_for_update = False
         query.select_related = False
         query.related_select_cols = []
-        query.related_select_fields = []
 
         result = query.get_compiler(using).execute_sql(SINGLE)
         if result is None:
@@ -527,14 +525,14 @@ class Query(object):
 
         # Selection columns and extra extensions are those provided by 'rhs'.
         self.select = []
-        for col in rhs.select:
+        for col, field in rhs.select:
             if isinstance(col, (list, tuple)):
-                self.select.append((change_map.get(col[0], col[0]), col[1]))
+                new_col = change_map.get(col[0], col[0]), col[1]
+                self.select.append(SelectInfo(new_col, field))
             else:
                 item = copy.deepcopy(col)
                 item.relabel_aliases(change_map)
-                self.select.append(item)
-        self.select_fields = rhs.select_fields[:]
+                self.select.append(SelectInfo(item, field))
 
         if connector == OR:
             # It would be nice to be able to handle this, but the queries don't
@@ -750,24 +748,23 @@ class Query(object):
         """
         assert set(change_map.keys()).intersection(set(change_map.values())) == set()
 
+        def relabel_column(col):
+            if isinstance(col, (list, tuple)):
+                old_alias = col[0]
+                return (change_map.get(old_alias, old_alias), col[1])
+            else:
+                col.relabel_aliases(change_map)
+                return col
         # 1. Update references in "select" (normal columns plus aliases),
         # "group by", "where" and "having".
         self.where.relabel_aliases(change_map)
         self.having.relabel_aliases(change_map)
-        for columns in [self.select, self.group_by or []]:
-            for pos, col in enumerate(columns):
-                if isinstance(col, (list, tuple)):
-                    old_alias = col[0]
-                    columns[pos] = (change_map.get(old_alias, old_alias), col[1])
-                else:
-                    col.relabel_aliases(change_map)
-        for mapping in [self.aggregates]:
-            for key, col in mapping.items():
-                if isinstance(col, (list, tuple)):
-                    old_alias = col[0]
-                    mapping[key] = (change_map.get(old_alias, old_alias), col[1])
-                else:
-                    col.relabel_aliases(change_map)
+        if self.group_by:
+            self.group_by = [relabel_column(col) for col in self.group_by]
+        self.select = [SelectInfo(relabel_column(s.col), s.field)
+                       for s in self.select]
+        self.aggregates = SortedDict(
+            (key, relabel_column(col)) for key, col in self.aggregates.items())
 
         # 2. Rename the alias in the internal table/alias datastructures.
         for k, aliases in self.join_map.items():
@@ -1570,7 +1567,7 @@ class Query(object):
         # since we are adding a IN <subquery> clause. This prevents the
         # database from tripping over IN (...,NULL,...) selects and returning
         # nothing
-        alias, col = query.select[0]
+        alias, col = query.select[0].col
         query.where.add((Constraint(alias, col, None), 'isnull', False), AND)
 
         self.add_filter(('%s__in' % prefix, query), negate=True, trim=True,
@@ -1629,7 +1626,6 @@ class Query(object):
         Removes all fields from SELECT clause.
         """
         self.select = []
-        self.select_fields = []
         self.default_cols = False
         self.select_related = False
         self.set_extra_mask(())
@@ -1642,7 +1638,6 @@ class Query(object):
         columns.
         """
         self.select = []
-        self.select_fields = []
 
     def add_distinct_fields(self, *field_names):
         """
@@ -1674,8 +1669,7 @@ class Query(object):
                         col = join.lhs_join_col
                         joins = joins[:-1]
                 self.promote_joins(joins[1:])
-                self.select.append((final_alias, col))
-                self.select_fields.append(field)
+                self.select.append(SelectInfo((final_alias, col), field))
         except MultiJoin:
             raise FieldError("Invalid field name: '%s'" % name)
         except FieldError:
@@ -1731,8 +1725,8 @@ class Query(object):
         """
         self.group_by = []
 
-        for sel in self.select:
-            self.group_by.append(sel)
+        for col, _ in self.select:
+            self.group_by.append(col)
 
     def add_count_column(self):
         """
@@ -1745,7 +1739,7 @@ class Query(object):
             else:
                 assert len(self.select) == 1, \
                         "Cannot add count col with multiple cols in 'select': %r" % self.select
-                count = self.aggregates_module.Count(self.select[0])
+                count = self.aggregates_module.Count(self.select[0].col)
         else:
             opts = self.model._meta
             if not self.select:
@@ -1757,7 +1751,7 @@ class Query(object):
                 assert len(self.select) == 1, \
                         "Cannot add count col with multiple cols in 'select'."
 
-                count = self.aggregates_module.Count(self.select[0], distinct=True)
+                count = self.aggregates_module.Count(self.select[0].col, distinct=True)
             # Distinct handling is done in Count(), so don't do it at this
             # level.
             self.distinct = False
@@ -1781,7 +1775,6 @@ class Query(object):
                 d = d.setdefault(part, {})
         self.select_related = field_dict
         self.related_select_cols = []
-        self.related_select_fields = []
 
     def add_extra(self, select, select_params, where, params, tables, order_by):
         """
@@ -1975,7 +1968,7 @@ class Query(object):
             self.unref_alias(select_alias)
             select_alias = join_info.rhs_alias
             select_col = join_info.rhs_join_col
-        self.select = [(select_alias, select_col)]
+        self.select = [SelectInfo((select_alias, select_col), None)]
         self.remove_inherited_models()
 
     def is_nullable(self, field):
diff --git a/django/db/models/sql/subqueries.py b/django/db/models/sql/subqueries.py
index 24ac957cbf..39d1ee0116 100644
--- a/django/db/models/sql/subqueries.py
+++ b/django/db/models/sql/subqueries.py
@@ -76,7 +76,7 @@ class DeleteQuery(Query):
                 return
             else:
                 innerq.clear_select_clause()
-                innerq.select, innerq.select_fields = [(self.get_initial_alias(), pk.column)], [None]
+                innerq.select = [SelectInfo((self.get_initial_alias(), pk.column), None)]
                 values = innerq
             where = self.where_class()
             where.add((Constraint(None, pk.column, pk), 'in', values), AND)
@@ -244,7 +244,7 @@ class DateQuery(Query):
         alias = result[3][-1]
         select = Date((alias, field.column), lookup_type)
         self.clear_select_clause()
-        self.select, self.select_fields = [select], [None]
+        self.select = [SelectInfo(select, None)]
         self.distinct = True
         self.order_by = order == 'ASC' and [1] or [-1]