added LockmodeArgspr/42

1 files changed, 21 insertions, 9 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index ec22e8633..089769975 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -1015,20 +1015,32 @@ class PGCompiler(compiler.SQLCompiler):
 
     def for_update_clause(self, select):
 
-        if select.for_update == 'read':
+        tmp = ' FOR UPDATE'
+
+        # backwards compatibility
+        if isinstance(select.for_update, bool):
+            return tmp
+        elif isinstance(select.for_update, str):
+            if select.for_update == 'nowait':
+                return tmp + ' NOWAIT'
+            elif select.for_update == 'read':
+                return ' FOR SHARE'
+            elif select.for_update == 'read_nowait':
+                return ' FOR SHARE NOWAIT'
+
+        if select.for_update.mode == 'read':
             return ' FOR SHARE'
-        elif select.for_update == 'read_nowait':
+        elif select.for_update.mode == 'read_nowait':
             return ' FOR SHARE NOWAIT'
 
-        tmp = ' FOR UPDATE'
-        if isinstance(select.for_update_of, list):
-            tmp += ' OF ' + ', '.join([of[0] for of in select.for_update_of])
-        elif isinstance(select.for_update_of, tuple):
-            tmp += ' OF ' + select.for_update_of[0]
+        if isinstance(select.for_update.of, list):
+            tmp += ' OF ' + ', '.join([of[0] for of in select.for_update.of])
+        elif isinstance(select.for_update.of, tuple):
+            tmp += ' OF ' + select.for_update.of[0]
 
-        if select.for_update == 'nowait':
+        if select.for_update.mode == 'update_nowait':
             return tmp + ' NOWAIT'
-        elif select.for_update:
+        elif select.for_update.mode == 'update':
             return tmp
         else:
             return super(PGCompiler, self).for_update_clause(select)