Enable user defined display_name for ScalarUDF

[yyy1000]

Which issue does this PR close?

Closes #10376 .

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[jayzhan211]

Do you mind adding display_name for get_field that shows what I expect in the example given in #10376?

[yyy1000]

Do you mind adding display_name for get_field that shows what I expect in the example given in #10376?

Cool, will do that.

[yyy1000]

It's good now. @jayzhan211 You can review it when you are available. :)
In this example

datafusion/datafusion/core/tests/user_defined/user_defined_aggregates.rs

Lines 165 to 176 in 96487ea

	async fn test_udaf_returning_struct_subquery() {
	let TestContext { ctx, test_state: _ } = TestContext::new();
	let sql = "select sq.first['value'], sq.first['time'] from (SELECT first(value, time) as first from t) as sq";
	let expected = [
	"+-----------------+----------------------------+",
	"| sq.first[value] | sq.first[time] |",
	"+-----------------+----------------------------+",
	"| 2.0 | 1970-01-01T00:00:00.000002 |",
	"+-----------------+----------------------------+",
	];
	assert_batches_eq!(expected, &execute(&ctx, sql).await.unwrap());
	}

, after apply_function_rewrites, the logical plan would not create an alias because the display_name of get_field is the same as sq.first[value]

In this PR:
"| initial_logical_plan | Projection: (sq.first)[value], (sq.first)[time] |",
"| | SubqueryAlias: sq |",
"| | Projection: first(t.value,t.time) AS first |",
"| | Aggregate: groupBy=[[]], aggr=[[first(t.value, t.time)]] |",
"| | TableScan: t |",
"| logical_plan after apply_function_rewrites | Projection: get_field(sq.first, Utf8("value")), get_field(sq.first, Utf8("time")) |",
"| | SubqueryAlias: sq |",
"| | Projection: first(t.value,t.time) AS first |",
"| | Aggregate: groupBy=[[]], aggr=[[first(t.value, t.time)]] |",
"| | TableScan: t |",

Before this PR:
"| initial_logical_plan | Projection: (sq.first)[value], (sq.first)[time] |",
"| | SubqueryAlias: sq |",
"| | Projection: first(t.value,t.time) AS first |",
"| | Aggregate: groupBy=[[]], aggr=[[first(t.value, t.time)]] |",
"| | TableScan: t |",
"| logical_plan after apply_function_rewrites | Projection: get_field(sq.first, Utf8("value")) AS sq.first[value], get_field(sq.first, Utf8("time")) AS sq.first[time] |",
"| | SubqueryAlias: sq |",
"| | Projection: first(t.value,t.time) AS first |",
"| | Aggregate: groupBy=[[]], aggr=[[first(t.value, t.time)]] |",
"| | TableScan: t |",
"| logical_plan after inline_table_scan | SAME TEXT AS ABOVE

[jayzhan211]

cli in this PR

DataFusion CLI v38.0.0
> select struct('a');
+-------------------+
| struct(Utf8("a")) |
+-------------------+
| {c0: a}           |
+-------------------+
1 row(s) fetched. 
Elapsed 0.023 seconds.

> select get_field(struct('a'), 'c0');
+-----------------------+
| struct(Utf8("a"))[c0] |
+-----------------------+
| a                     |
+-----------------------+
1 row(s) fetched. 
Elapsed 0.007 seconds.

main branch:

DataFusion CLI v38.0.0
> select struct('a');
+-------------------+
| struct(Utf8("a")) |
+-------------------+
| {c0: a}           |
+-------------------+
1 row(s) fetched. 
Elapsed 0.014 seconds.

> select get_field(struct('a'), 'c0');
+-----------------------------------------+
| get_field(struct(Utf8("a")),Utf8("c0")) |
+-----------------------------------------+
| a                                       |
+-----------------------------------------+
1 row(s) fetched. 
Elapsed 0.004 seconds.

[yyy1000]

Yeah, this example has better view. 🙌

[jayzhan211]

👍

[alamb]

Thanks @yyy1000 and @jayzhan211