regexp_replace fails when pattern or replacement is a scalar NULL

[Blizzara]

Describe the bug

regexp_replace fails to produce correct number of rows if either pattern or replacement arg is a scalar NULL.

I think this is due to

datafusion/datafusion/functions/src/regex/regexpreplace.rs

Line 316 in 7a23ea9

let pattern = fetch_string_arg!(&args[1], "pattern", T, _regexp_replace_early_abort);

fetch_string_arg not passing the correct length to the _regexp_replace_early_abort function - when this specific arg is a scalar, its "array len" is just 1, and the abort function creates a 1-len array as the result.

To Reproduce

Normal case - values are valid scalars or array nulls:

> select regexp_replace(col, 'a', 'c') from (values ('a'), ('b')) as tbl(col);
+---------------------------------------------+
| regexp_replace(tbl.col,Utf8("a"),Utf8("c")) |
+---------------------------------------------+
| c                                           |
| b                                           |
+---------------------------------------------+
2 row(s) fetched. 
Elapsed 0.001 seconds.

> select regexp_replace(col, ncol, 'c') from (values ('a', NULL), ('b', NULL)) as tbl(col, ncol);
+--------------------------------------------+
| regexp_replace(tbl.col,tbl.ncol,Utf8("c")) |
+--------------------------------------------+
|                                            |
|                                            |
+--------------------------------------------+

Failing case - pattern or replacement is a scalar NULL:

> select regexp_replace(col, NULL, 'c') from (values ('a'), ('b')) as tbl(col);
Internal error: UDF returned a different number of rows than expected. Expected: 2, Got: 1.
This was likely caused by a bug in DataFusion's code and we would welcome that you file an bug report in our issue tracker

> select regexp_replace(col, 'a', NULL) from (values ('a'), ('b')) as tbl(col);
Internal error: UDF returned a different number of rows than expected. Expected: 2, Got: 1.
This was likely caused by a bug in DataFusion's code and we would welcome that you file an bug report in our issue tracker

Expected behavior

No response

Additional context

No response

[Weijun-H]

take