[WIP] Fix problem in NestedColumnAliasing.scala , replaceWithAliases in connection with Generate plan node

[trohwer]

When one uses replaceWithChildren, one has to be careful with Generate plan nodes. Generate contains a list unrequiredChildIndex of unneeded child outputs in the Generate output. This data has to be adjusted accordingly. Otherwise an incorrect plan may be generated during optimisation. Here is an example (tested with Spark 3.5.3):

from pyspark.sql import SparkSession
session= SparkSession.builder.master("local").getOrCreate()
session.sql("""
select
named_struct(
'b', '',
'c', '',
'd', array(named_struct('f', '', 'g', '')),
'e', ''
) as a
""").write.mode("overwrite").parquet("tmp")
df= session.read.parquet("tmp")
df.createOrReplaceTempView("tmp")
sql="""
SELECT
a.b f1, a.c f2, x.f,
STACK(1, y) as (z)
FROM tmp
LATERAL VIEW POSEXPLODE_OUTER(a.d) as y, x
"""
session.sql(sql).explain()
#== Physical Plan == #*(1) !Project [_extract_b#21 AS f1#5, _extract_c#19 AS f2#6, _extract_f#20 AS f#12, z#13]
#+- *(1) Generate stack(1, y#8), [_extract_b#21, _extract_f#20], false, [z#13]
# +- *(1) Project [_extract_b#21, y#8, x#9 AS _extract_f#20]
# +- *(1) Generate posexplode(_extract_f#26), [_extract_b#21], true, [y#8, x#9]
# +- *(1) Project [a#3.b AS _extract_b#21, a#3.d.f AS _extract_f#26]
# +- *(1) ColumnarToRow
# +- FileScan parquet [a#3] Batched: true, DataFilters: [], Format: Parquet, Location: InMemoryFileIndex(1 paths)[file:/home/pa/test/spark-bug/tmp], PartitionFilters: [], PushedFilters: [], ReadSchema: struct<a:struct<b:string,d:array<struct<f:string>>>>
session.sql(sql).show()
# java.lang.IllegalStateException: Couldn't find _extract_c#54 in [_extract_b#56,_extract_f#55,z#36]

One can see, that the generated plan is invalid (extract_c#19 is missing in the in previous Project) and yields an error during execution. With this fix, the problem does not occur.

[github-actions]

We're closing this PR because it hasn't been updated in a while. This isn't a judgement on the merit of the PR in any way. It's just a way of keeping the PR queue manageable.
If you'd like to revive this PR, please reopen it and ask a committer to remove the Stale tag!