Removed obsolete Query.tables attribute.

Obsolete since Query.alias_map became an OrderedDict (refs #26522).

3 files changed, 26 insertions, 23 deletions

diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index c2fa0bab29..b4b27a5b56 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -31,7 +31,7 @@ class SQLCompiler:
         self.ordering_parts = re.compile(r'(.*)\s(ASC|DESC)(.*)')
 
     def setup_query(self):
-        if all(self.query.alias_refcount[a] == 0 for a in self.query.tables):
+        if all(self.query.alias_refcount[a] == 0 for a in self.query.alias_map):
             self.query.get_initial_alias()
         self.select, self.klass_info, self.annotation_col_map = self.get_select()
         self.col_count = len(self.select)
@@ -141,7 +141,7 @@ class SQLCompiler:
                 # Is this a reference to query's base table primary key? If the
                 # expression isn't a Col-like, then skip the expression.
                 if (getattr(expr, 'target', None) == self.query.model._meta.pk and
-                        getattr(expr, 'alias', None) == self.query.tables[0]):
+                        getattr(expr, 'alias', None) == self.query.base_table):
                     pk = expr
                     break
             # If the main model's primary key is in the query, group by that
@@ -681,7 +681,7 @@ class SQLCompiler:
         """
         result = []
         params = []
-        for alias in self.query.tables:
+        for alias in self.query.alias_map:
             if not self.query.alias_refcount[alias]:
                 continue
             try:
@@ -1149,10 +1149,10 @@ class SQLDeleteCompiler(SQLCompiler):
         Create the SQL for this query. Return the SQL string and list of
         parameters.
         """
-        assert len([t for t in self.query.tables if self.query.alias_refcount[t] > 0]) == 1, \
+        assert len([t for t in self.query.alias_map if self.query.alias_refcount[t] > 0]) == 1, \
             "Can only delete from one table at a time."
         qn = self.quote_name_unless_alias
-        result = ['DELETE FROM %s' % qn(self.query.tables[0])]
+        result = ['DELETE FROM %s' % qn(self.query.base_table)]
         where, params = self.compile(self.query.where)
         if where:
             result.append('WHERE %s' % where)
@@ -1205,7 +1205,7 @@ class SQLUpdateCompiler(SQLCompiler):
                 update_params.append(val)
             else:
                 values.append('%s = NULL' % qn(name))
-        table = self.query.tables[0]
+        table = self.query.base_table
         result = [
             'UPDATE %s SET' % qn(table),
             ', '.join(values),
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index d3ab487ba7..b4a87938f7 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -30,6 +30,7 @@ from django.db.models.sql.where import (
     AND, OR, ExtraWhere, NothingNode, WhereNode,
 )
 from django.utils.encoding import force_text
+from django.utils.functional import cached_property
 from django.utils.tree import Node
 
 __all__ = ['Query', 'RawQuery']
@@ -144,7 +145,6 @@ class Query:
         # clause to contain other than default fields (values(), subqueries...)
         # Note that annotations go to annotations dictionary.
         self.select = ()
-        self.tables = ()  # Aliases in the order they are created.
         self.where = where()
         self.where_class = where
         # The group_by attribute can have one of the following forms:
@@ -217,6 +217,10 @@ class Query:
     def has_select_fields(self):
         return bool(self.select or self.annotation_select_mask or self.extra_select_mask)
 
+    @cached_property
+    def base_table(self):
+        return list(self.alias_map)[0] if self.alias_map else None
+
     def __str__(self):
         """
         Return the query as a string of SQL with the parameter values
@@ -274,7 +278,6 @@ class Query:
         obj.default_ordering = self.default_ordering
         obj.standard_ordering = self.standard_ordering
         obj.select = self.select
-        obj.tables = self.tables
         obj.where = self.where.clone()
         obj.where_class = self.where_class
         obj.group_by = self.group_by
@@ -431,7 +434,7 @@ class Query:
                     inner_query.group_by = (self.model._meta.pk.get_col(inner_query.get_initial_alias()),)
                 inner_query.default_cols = False
 
-            relabels = {t: 'subquery' for t in inner_query.tables}
+            relabels = {t: 'subquery' for t in inner_query.alias_map}
             relabels[None] = 'subquery'
             # Remove any aggregates marked for reduction from the subquery
             # and move them to the outer AggregateQuery.
@@ -539,7 +542,7 @@ class Query:
         # Note that we will be creating duplicate joins for non-m2m joins in
         # the AND case. The results will be correct but this creates too many
         # joins. This is something that could be fixed later on.
-        reuse = set() if conjunction else set(self.tables)
+        reuse = set() if conjunction else set(self.alias_map)
         # Base table must be present in the query - this is the same
         # table on both sides.
         self.get_initial_alias()
@@ -549,7 +552,8 @@ class Query:
         rhs_votes = set()
         # Now, add the joins from rhs query into the new query (skipping base
         # table).
-        for alias in rhs.tables[1:]:
+        rhs_tables = list(rhs.alias_map)[1:]
+        for alias in rhs_tables:
             join = rhs.alias_map[alias]
             # If the left side of the join was already relabeled, use the
             # updated alias.
@@ -714,7 +718,6 @@ class Query:
             alias = table_name
             self.table_map[alias] = [alias]
         self.alias_refcount[alias] = 1
-        self.tables += (alias,)
         return alias, True
 
     def ref_alias(self, alias):
@@ -864,12 +867,9 @@ class Query:
         self.subq_aliases = self.subq_aliases.union([self.alias_prefix])
         outer_query.subq_aliases = outer_query.subq_aliases.union(self.subq_aliases)
         change_map = OrderedDict()
-        tables = list(self.tables)
-        for pos, alias in enumerate(tables):
+        for pos, alias in enumerate(self.alias_map):
             new_alias = '%s%d' % (self.alias_prefix, pos)
             change_map[alias] = new_alias
-            tables[pos] = new_alias
-        self.tables = tuple(tables)
         self.change_aliases(change_map)
 
     def get_initial_alias(self):
@@ -877,8 +877,8 @@ class Query:
         Return the first alias for this query, after increasing its reference
         count.
         """
-        if self.tables:
-            alias = self.tables[0]
+        if self.alias_map:
+            alias = self.base_table
             self.ref_alias(alias)
         else:
             alias = self.join(BaseTable(self.get_meta().db_table, None))
@@ -1910,7 +1910,10 @@ class Query:
         # Trim and operate only on tables that were generated for
         # the lookup part of the query. That is, avoid trimming
         # joins generated for F() expressions.
-        lookup_tables = [t for t in self.tables if t in self._lookup_joins or t == self.tables[0]]
+        lookup_tables = [
+            t for t in self.alias_map
+            if t in self._lookup_joins or t == self.base_table
+        ]
         for trimmed_paths, path in enumerate(all_paths):
             if path.m2m:
                 break
@@ -1950,7 +1953,7 @@ class Query:
             select_alias = lookup_tables[trimmed_paths]
         # The found starting point is likely a Join instead of a BaseTable reference.
         # But the first entry in the query's FROM clause must not be a JOIN.
-        for table in self.tables:
+        for table in self.alias_map:
             if self.alias_refcount[table] > 0:
                 self.alias_map[table] = BaseTable(self.alias_map[table].table_name, table)
                 break
diff --git a/django/db/models/sql/subqueries.py b/django/db/models/sql/subqueries.py
index 53f975a1e9..0011a0dadd 100644
--- a/django/db/models/sql/subqueries.py
+++ b/django/db/models/sql/subqueries.py
@@ -19,7 +19,7 @@ class DeleteQuery(Query):
     compiler = 'SQLDeleteCompiler'
 
     def do_query(self, table, where, using):
-        self.tables = (table,)
+        self.alias_map = {table: self.alias_map[table]}
         self.where = where
         cursor = self.get_compiler(using).execute_sql(CURSOR)
         return cursor.rowcount if cursor else 0
@@ -52,8 +52,8 @@ class DeleteQuery(Query):
         innerq.get_initial_alias()
         # The same for our new query.
         self.get_initial_alias()
-        innerq_used_tables = tuple([t for t in innerq.tables if innerq.alias_refcount[t]])
-        if not innerq_used_tables or innerq_used_tables == self.tables:
+        innerq_used_tables = tuple([t for t in innerq.alias_map if innerq.alias_refcount[t]])
+        if not innerq_used_tables or innerq_used_tables == tuple(self.alias_map):
             # There is only the base table in use in the query.
             self.where = innerq.where
         else: