EnricoMi opened a new pull request, #38676:
URL: https://github.com/apache/spark/pull/38676
### What changes were proposed in this pull request?
Rule `PushDownLeftSemiAntiJoin` should not push an anti-join below an
`Aggregate` when the translated (cf. `aliasMap`) join conditions become
ambiguous w.r.t. to both join sides.
### Why are the changes needed?
The following example fails with `distinct()`, and succeeds without
`distinct()`, but both queries are identical.
```scala
val ids = Seq(1, 2, 3).toDF("id").distinct()
val result = ids.withColumn("id", $"id" + 1).join(ids, "id",
"left_anti").collect()
assert(result.length == 1)
```
With `distinct()`, rule `PushDownLeftSemiAntiJoin` creates a join condition
`(id#750 + 1) = id#750`, which can never be true. This effectively removes the
anti-join.
### Does this PR introduce _any_ user-facing change?
It fixes correctness.
### How was this patch tested?
Unit test.
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