[FIX] base: unlink request.cr after rpc db drop

Start odoo on a specific database, e.g. 'db-example'. Drop it via JSON
or XML RPC. The database is successfully dropped but the RPC fails with
a traceback because it attempts to commit on a database that doesn't
exist anymore.

    import requests

    admin_passwd = ...
    requests.post(
        'http://127.0.0.1:8069/jsonrpc',
        json={'params': {
            'service': 'db',
            'method': 'drop',
            'args': [
                admin_passwd, 'db-example'
            ]
        }}
    )

Closes odoo#104527

closes odoo/odoo#105710

X-original-commit: b6e195ccb3a6c37b0d980af159e546bdc67b1e42
Signed-off-by: Julien Castiaux <juc@odoo.com>

addons/web/controllers/database.py

@@ -116,8 +116,6 @@ class Database(http.Controller):
             dispatch_rpc('db', 'change_admin_password', ["admin", master_pwd])
         try:
             dispatch_rpc('db', 'drop', [master_pwd, name])
-            if request.db == name:
-                request.env.cr._closed = True  # the underlying connection was closed
             if request.session.db == name:
                 request.session.logout()
             return request.redirect('/web/database/manager')

odoo/service/model.py

@@ -161,7 +161,7 @@ def retrying(func, env):
         env.registry.reset_changes()
         raise
 
-    if not env.cr._closed:
+    if not env.cr.closed:
         env.cr.commit()  # effectively commits and execute post-commits
     env.registry.signal_changes()
     return result

odoo/sql_db.py

@@ -391,7 +391,7 @@ class Cursor(BaseCursor):
             _logger.setLevel(level)
 
     def close(self):
-        if not self._closed:
+        if not self.closed:
             return self._close(False)
 
     def _close(self, leak=False):
@@ -463,7 +463,7 @@ class Cursor(BaseCursor):
 
     @property
     def closed(self):
-        return self._closed
+        return self._closed or self._cnx.closed
 
     def now(self):
         """ Return the transaction's timestamp ``NOW() AT TIME ZONE 'UTC'``. """