fix: don't leak joined branch's sort into implicit ORDER BY for take#6015
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lukapeschke wants to merge 1 commit into
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fix: don't leak joined branch's sort into implicit ORDER BY for take#6015lukapeschke wants to merge 1 commit into
lukapeschke wants to merge 1 commit into
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When a pipeline sorts both the left and the joined branch (both wrapped in CTEs by a preceding `group`) and is then truncated with `take`, prqlc synthesized the implicit ORDER BY for the LIMIT from the *joined* branch's sort column. That column is anchored to the joined branch's source table, which is no longer in scope once the branch is materialized as a CTE, producing invalid SQL (e.g. `ORDER BY bar.a` where `bar` lives inside a CTE). The `Flattener` folds a join's input (left) first, setting the running sort frame to the left's order, then folds the join's `with` sub-pipeline, which overwrote the frame with the right branch's sort. The join transform's own sort was cleared, but `self.sort` was left pointing at the joined branch, so downstream transforms (`take`) inherited the wrong column. Snapshot and restore the input's sort frame around folding a join/append kind, implementing the documented "a join retains the left side's order" semantic. The implicit ORDER BY now references the left CTE alias. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Jun 17, 2026
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When a pipeline sorts both the left and the joined branch (both wrapped in CTEs by a preceding
group) and is then truncated withtake, prqlc synthesized the implicit ORDER BY for the LIMIT from the joined branch's sort column. That column is anchored to the joined branch's source table, which is no longer in scope once the branch is materialized as a CTE, producing invalid SQL (e.g.ORDER BY bar.awherebarlives inside a CTE).The
Flattenerfolds a join's input (left) first, setting the running sort frame to the left's order, then folds the join'swithsub-pipeline, which overwrote the frame with the right branch's sort. The join transform's own sort was cleared, butself.sortwas left pointing at the joined branch, so downstream transforms (take) inherited the wrong column.Snapshot and restore the input's sort frame around folding a join/append kind, implementing the documented "a join retains the left side's order" semantic. The implicit ORDER BY now references the left CTE alias.