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Simplified Query.build_lookup()
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@ -1109,29 +1109,49 @@ class Query(object):
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self.check_query_object_type(v, opts)
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def build_lookup(self, lookups, lhs, rhs):
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"""
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Tries to extract transforms and lookup from given lhs.
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The lhs value is something that works like SQLExpression.
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The rhs value is what the lookup is going to compare against.
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The lookups is a list of names to extract using get_lookup()
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and get_transform().
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"""
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lookups = lookups[:]
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bilaterals = []
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while lookups:
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lookup = lookups[0]
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name = lookups[0]
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# If there is just one part left, try first get_lookup() so
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# that if the lhs supports both transform and lookup for the
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# name, then lookup will be picked.
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if len(lookups) == 1:
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final_lookup = lhs.get_lookup(lookup)
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if final_lookup:
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return final_lookup(lhs, rhs, bilaterals)
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# We didn't find a lookup, so we are going to try get_transform
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# + get_lookup('exact').
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lookups.append('exact')
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next = lhs.get_transform(lookup)
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if next:
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lhs = next(lhs, lookups)
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if getattr(next, 'bilateral', False):
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bilaterals.append((next, lookups))
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else:
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raise FieldError(
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"Unsupported lookup '%s' for %s or join on the field not "
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"permitted." %
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(lookup, lhs.output_field.__class__.__name__))
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final_lookup = lhs.get_lookup(name)
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if not final_lookup:
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# We didn't find a lookup. We are going to interpret
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# the name as transform, and do an Exact lookup against
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# it.
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lhs = self.try_transform(lhs, name, lookups, bilaterals)
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final_lookup = lhs.get_lookup('exact')
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return final_lookup(lhs, rhs, bilaterals)
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lhs = self.try_transform(lhs, name, lookups, bilaterals)
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lookups = lookups[1:]
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def try_transform(self, lhs, name, rest_of_lookups, bilaterals):
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"""
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Helper method for build_lookup. Tries to fetch and initialize
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a transform for name parameter from lhs.
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"""
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next = lhs.get_transform(name)
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if next:
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if getattr(next, 'bilateral', False):
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bilaterals.append((next, rest_of_lookups))
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return next(lhs, rest_of_lookups)
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else:
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raise FieldError(
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"Unsupported lookup '%s' for %s or join on the field not "
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"permitted." %
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(name, lhs.output_field.__class__.__name__))
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def build_filter(self, filter_expr, branch_negated=False, current_negated=False,
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can_reuse=None, connector=AND):
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"""
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