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Refs #32940 -- Removed unnecessary branch in Node.add().
The "data in self.children" branch was causing data.__eq__ to be called for each entries in "self.children" which resulted in a huge slowdown during queryset construction. It's purpose was to prevent queries of the form Model.objects.filter(foo='bar').filter(foo='bar') from resulting in WHERE foo='bar' AND foo='bar' but it's not covered by the suite and has arguable performance benefits since it's not very common and SQL engines are usually very good at folding/optimizing these. See also #32632 for prior discussion around comparing data to the Node's children. Co-authored-by: Nick Pope <nick@nickpope.me.uk>
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@ -88,31 +88,28 @@ class Node:
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Return a node which can be used in place of data regardless if the
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node other got squashed or not.
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"""
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if self.connector == conn_type and data in self.children:
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return data
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if self.connector == conn_type:
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# We can reuse self.children to append or squash the node other.
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if (isinstance(data, Node) and not data.negated and
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(data.connector == conn_type or len(data) == 1)):
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# We can squash the other node's children directly into this
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# node. We are just doing (AB)(CD) == (ABCD) here, with the
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# addition that if the length of the other node is 1 the
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# connector doesn't matter. However, for the len(self) == 1
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# case we don't want to do the squashing, as it would alter
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# self.connector.
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self.children.extend(data.children)
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return self
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else:
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# We could use perhaps additional logic here to see if some
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# children could be used for pushdown here.
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self.children.append(data)
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return data
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else:
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obj = self._new_instance(self.children, self.connector,
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self.negated)
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if self.connector != conn_type:
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obj = self._new_instance(self.children, self.connector, self.negated)
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self.connector = conn_type
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self.children = [obj, data]
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return data
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elif (
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isinstance(data, Node) and
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not data.negated and
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(data.connector == conn_type or len(data) == 1)
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):
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# We can squash the other node's children directly into this node.
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# We are just doing (AB)(CD) == (ABCD) here, with the addition that
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# if the length of the other node is 1 the connector doesn't
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# matter. However, for the len(self) == 1 case we don't want to do
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# the squashing, as it would alter self.connector.
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self.children.extend(data.children)
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return self
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else:
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# We could use perhaps additional logic here to see if some
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# children could be used for pushdown here.
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self.children.append(data)
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return data
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def negate(self):
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"""Negate the sense of the root connector."""
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