From 69968dec867053e38de0b91d76ac41d5a5735e36 Mon Sep 17 00:00:00 2001
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From: Vendula Poncova <vponcova@redhat.com>
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Date: Thu, 2 Aug 2018 15:31:56 +0800
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Subject: [PATCH 2/2] Support transformation between D-Bus errors and
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exceptions.
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Exceptions can be registered with decorators, raised in a remote
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method and recreated after return from the remote call.
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Upstream-Status: Cherry-pick [https://src.fedoraproject.org/cgit/rpms/python-pydbus.git/]
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Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
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---
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pydbus/error.py | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++
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pydbus/proxy_method.py | 18 ++++++++--
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pydbus/registration.py | 16 ++++++---
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3 files changed, 123 insertions(+), 8 deletions(-)
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create mode 100644 pydbus/error.py
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diff --git a/pydbus/error.py b/pydbus/error.py
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new file mode 100644
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index 0000000..aaa3510
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--- /dev/null
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+++ b/pydbus/error.py
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@@ -0,0 +1,97 @@
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+from gi.repository import GLib, Gio
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+
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+
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+def register_error(name, domain, code):
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+ """Register and map decorated exception class to a DBus error."""
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+ def decorated(cls):
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+ error_registration.register_error(cls, name, domain, code)
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+ return cls
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+
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+ return decorated
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+
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+
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+def map_error(error_name):
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+ """Map decorated exception class to a DBus error."""
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+ def decorated(cls):
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+ error_registration.map_error(cls, error_name)
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+ return cls
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+
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+ return decorated
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+
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+
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+def map_by_default(cls):
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+ """Map decorated exception class to all unknown DBus errors."""
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+ error_registration.map_by_default(cls)
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+ return cls
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+
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+
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+class ErrorRegistration(object):
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+ """Class for mapping exceptions to DBus errors."""
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+
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+ _default = None
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+ _map = dict()
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+ _reversed_map = dict()
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+
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+ def map_by_default(self, exception_cls):
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+ """Set the exception class as a default."""
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+ self._default = exception_cls
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+
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+ def map_error(self, exception_cls, name):
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+ """Map the exception class to a DBus name."""
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+ self._map[name] = exception_cls
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+ self._reversed_map[exception_cls] = name
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+
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+ def register_error(self, exception_cls, name, domain, code):
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+ """Map and register the exception class to a DBus name."""
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+ self.map_error(exception_cls, name)
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+ return Gio.DBusError.register_error(domain, code, name)
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+
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+ def is_registered_exception(self, obj):
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+ """Is the exception registered?"""
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+ return obj.__class__ in self._reversed_map
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+
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+ def get_dbus_name(self, obj):
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+ """Get the DBus name of the exception."""
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+ return self._reversed_map.get(obj.__class__)
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+
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+ def get_exception_class(self, name):
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+ """Get the exception class mapped to the DBus name."""
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+ return self._map.get(name, self._default)
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+
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+ def transform_message(self, name, message):
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+ """Transform the message of the exception."""
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+ prefix = "{}:{}: ".format("GDBus.Error", name)
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+
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+ if message.startswith(prefix):
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+ return message[len(prefix):]
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+
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+ return message
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+
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+ def transform_exception(self, e):
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+ """Transform the remote error to the exception."""
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+ if not isinstance(e, GLib.Error):
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+ return e
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+
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+ if not Gio.DBusError.is_remote_error(e):
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+ return e
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+
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+ # Get DBus name of the error.
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+ name = Gio.DBusError.get_remote_error(e)
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+ # Get the exception class.
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+ exception_cls = self.get_exception_class(name)
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+
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+ # Return the original exception.
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+ if not exception_cls:
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+ return e
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+
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+ # Return new exception.
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+ message = self.transform_message(name, e.message)
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+ exception = exception_cls(message)
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+ exception.dbus_name = name
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+ exception.dbus_domain = e.domain
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+ exception.dbus_code = e.code
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+ return exception
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+
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+
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+# Default error registration.
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+error_registration = ErrorRegistration()
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diff --git a/pydbus/proxy_method.py b/pydbus/proxy_method.py
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index 4ea4304..e9496f5 100644
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--- a/pydbus/proxy_method.py
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+++ b/pydbus/proxy_method.py
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@@ -2,6 +2,7 @@ from gi.repository import GLib
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from .generic import bound_method
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from .identifier import filter_identifier
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from .timeout import timeout_to_glib
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+from .error import error_registration
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try:
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from inspect import Signature, Parameter
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@@ -87,9 +88,20 @@ class ProxyMethod(object):
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call_args += (self._finish_async_call, (callback, callback_args))
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instance._bus.con.call(*call_args)
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return None
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+
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else:
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- ret = instance._bus.con.call_sync(*call_args)
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- return self._unpack_return(ret)
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+ result = None
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+ error = None
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+
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+ try:
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+ result = instance._bus.con.call_sync(*call_args)
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+ except Exception as e:
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+ error = error_registration.transform_exception(e)
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+
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+ if error:
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+ raise error
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+
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+ return self._unpack_return(result)
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def _unpack_return(self, values):
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ret = values.unpack()
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@@ -108,7 +120,7 @@ class ProxyMethod(object):
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ret = source.call_finish(result)
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return_args = self._unpack_return(ret)
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except Exception as err:
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- error = err
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+ error = error_registration.transform_exception(err)
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callback, callback_args = user_data
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callback(*callback_args, returned=return_args, error=error)
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diff --git a/pydbus/registration.py b/pydbus/registration.py
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index f531539..1d2cbcb 100644
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--- a/pydbus/registration.py
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+++ b/pydbus/registration.py
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@@ -5,6 +5,7 @@ from . import generic
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from .exitable import ExitableWithAliases
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from functools import partial
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from .method_call_context import MethodCallContext
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+from .error import error_registration
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import logging
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try:
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@@ -91,11 +92,16 @@ class ObjectWrapper(ExitableWithAliases("unwrap")):
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logger = logging.getLogger(__name__)
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logger.exception("Exception while handling %s.%s()", interface_name, method_name)
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- #TODO Think of a better way to translate Python exception types to DBus error types.
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- e_type = type(e).__name__
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- if not "." in e_type:
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- e_type = "unknown." + e_type
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- invocation.return_dbus_error(e_type, str(e))
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+ if error_registration.is_registered_exception(e):
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+ name = error_registration.get_dbus_name(e)
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+ invocation.return_dbus_error(name, str(e))
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+ else:
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+ logger.info("name is not registered")
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+ e_type = type(e).__name__
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+ if not "." in e_type:
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+ e_type = "unknown." + e_type
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+
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+ invocation.return_dbus_error(e_type, str(e))
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def Get(self, interface_name, property_name):
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type = self.readable_properties[interface_name + "." + property_name]
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--
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2.7.4
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