### What changes were proposed in this pull request?
To fix lambda variable name issues in nested DataFrame functions, this PR modifies code to use a global counter for `LambdaVariables` names created by higher order functions.
This is the rework of #31887. Closes#31887.
### Why are the changes needed?
This moves away from the current hard-coded variable names which break on nested function calls. There is currently a bug where nested transforms in particular fail (the inner variable shadows the outer variable)
For this query:
```
val df = Seq(
(Seq(1,2,3), Seq("a", "b", "c"))
).toDF("numbers", "letters")
df.select(
f.flatten(
f.transform(
$"numbers",
(number: Column) => { f.transform(
$"letters",
(letter: Column) => { f.struct(
number.as("number"),
letter.as("letter")
) }
) }
)
).as("zipped")
).show(10, false)
```
This is the current (incorrect) output:
```
+------------------------------------------------------------------------+
|zipped |
+------------------------------------------------------------------------+
|[{a, a}, {b, b}, {c, c}, {a, a}, {b, b}, {c, c}, {a, a}, {b, b}, {c, c}]|
+------------------------------------------------------------------------+
```
And this is the correct output after fix:
```
+------------------------------------------------------------------------+
|zipped |
+------------------------------------------------------------------------+
|[{1, a}, {1, b}, {1, c}, {2, a}, {2, b}, {2, c}, {3, a}, {3, b}, {3, c}]|
+------------------------------------------------------------------------+
```
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Added the new test in `DataFrameFunctionsSuite`.
Closes#32424 from maropu/pr31887.
Lead-authored-by: dsolow <dsolow@sayari.com>
Co-authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Co-authored-by: dmsolow <dsolow@sayarianalytics.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
f550e03b96