Fixed #23853 -- Added Join class to replace JoinInfo

Also removed Query.join_map. This structure was used to speed up join
reuse calculation. Initial benchmarking shows that this isn't actually
needed. If there are use cases where the removal has real-world
performance implications, it should be relatively straightforward to
reintroduce it as map {alias: [Join-like objects]}.

1 files changed, 4 insertions, 6 deletions

diff --git a/django/db/models/sql/constants.py b/django/db/models/sql/constants.py
index 49fdf114b3..e0e3f10100 100644
--- a/django/db/models/sql/constants.py
+++ b/django/db/models/sql/constants.py
@@ -21,12 +21,6 @@ GET_ITERATOR_CHUNK_SIZE = 100
 
 # Namedtuples for sql.* internal use.
 
-# Join lists (indexes into the tuples that are values in the alias_map
-# dictionary in the Query class).
-JoinInfo = namedtuple('JoinInfo',
-                      'table_name rhs_alias join_type lhs_alias '
-                      'join_cols nullable join_field')
-
 # Pairs of column clauses to select, and (possibly None) field for the clause.
 SelectInfo = namedtuple('SelectInfo', 'col field')
 
@@ -41,3 +35,7 @@ ORDER_DIR = {
     'ASC': ('ASC', 'DESC'),
     'DESC': ('DESC', 'ASC'),
 }
+
+# SQL join types.
+INNER = 'INNER JOIN'
+LOUTER = 'LEFT OUTER JOIN'