#31097: StringAgg And ArrayAgg with filtering in subquery generates invalid
string_agg() SQL function call
-------------------------------------+-------------------------------------
Reporter: Laurent Tramoy | Owner: David
| Wobrock
Type: Bug | Status: assigned
Component: contrib.postgres | Version: 3.0
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by David Wobrock):
* status: new => assigned
* owner: (none) => David Wobrock
Comment:
Hi, I'm claiming the ticket if nobody bothers.
I already wrote a testcase that reproduced the bug and started to pin down
the source of the issue.
The first (very) technical info I found:
It seems to be linked to the logic of relabeling aliases of the the filter
clause in {{{django.db.models.sql.query.Query.change_aliases}}}, in the
{{{self.where.relabel_aliases(change_map)}}} logic.
The first node itself is a {{{WhereNode}}} containing {{{(AND: (NOT (AND:
<django.db.models.lookups.Exact object at 0x7f9ea9bfc9b0>)))}}}
When going down the filter tree, we first hit again a {{{WhereNode}}} with
the negation: {{{(NOT (AND: <django.db.models.lookups.Exact object at
0x7f9ea9bfc9b0>))}}} for our exclude clause.
Finally coming to the {{{Exact}}} object, we relabel the left hand-side of
the condition, being the {{{StringAgg}}}.
This calls the
{{{django.db.models.expressions.BaseExpression.relabeled_clone}}} where we
depend on the fields found by {{{self.get_source_expressions()}}}
Either, those source expressions are incomplete because of the way the
{{{OrderableAggMixin}}} plays with the {{{self.get_source_expressions()}}}
(not calling the super), or the {{{change_map}}} which is passed down is
missing some potential aliases.
I'll try to keep investigating and propose a patch in the coming weeks :)
--
Ticket URL: <https://code.djangoproject.com/ticket/31097#comment:3>
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