Fix strpos invocation with dictionary and null (#12712)

In 1b3608d `strpos` signature was
modified to indicate it supports dictionary as input argument, but the
invoke method doesn't support them.

Author: findepi

datafusion/functions/src/unicode/strpos.rs

@@ -23,7 +23,8 @@ use arrow::datatypes::{ArrowNativeType, DataType, Int32Type, Int64Type};
 
 use crate::string::common::StringArrayType;
 use crate::utils::{make_scalar_function, utf8_to_int_type};
-use datafusion_common::{exec_err, plan_err, Result};
+use datafusion_common::{exec_err, Result};
+use datafusion_expr::TypeSignature::Exact;
 use datafusion_expr::{ColumnarValue, ScalarUDFImpl, Signature, Volatility};
 
 #[derive(Debug)]
@@ -40,8 +41,20 @@ impl Default for StrposFunc {
 
 impl StrposFunc {
     pub fn new() -> Self {
+        use DataType::*;
         Self {
-            signature: Signature::user_defined(Volatility::Immutable),
+            signature: Signature::one_of(
+                vec![
+                    Exact(vec![Utf8, Utf8]),
+                    Exact(vec![Utf8, LargeUtf8]),
+                    Exact(vec![LargeUtf8, Utf8]),
+                    Exact(vec![LargeUtf8, LargeUtf8]),
+                    Exact(vec![Utf8View, Utf8View]),
+                    Exact(vec![Utf8View, Utf8]),
+                    Exact(vec![Utf8View, LargeUtf8]),
+                ],
+                Volatility::Immutable,
+            ),
             aliases: vec![String::from("instr"), String::from("position")],
         }
     }
@@ -71,25 +84,6 @@ impl ScalarUDFImpl for StrposFunc {
     fn aliases(&self) -> &[String] {
         &self.aliases
     }
-
-    fn coerce_types(&self, arg_types: &[DataType]) -> Result<Vec<DataType>> {
-        match arg_types {
-            [first, second ] => {
-                match (first, second) {
-                    (DataType::LargeUtf8 | DataType::Utf8View | DataType::Utf8, DataType::LargeUtf8 | DataType::Utf8View | DataType::Utf8) => Ok(arg_types.to_vec()),
-                    (DataType::Null, DataType::Null)   => Ok(vec![DataType::Utf8, DataType::Utf8]),
-                    (DataType::Null, _)   => Ok(vec![DataType::Utf8, second.to_owned()]),
-                    (_, DataType::Null) => Ok(vec![first.to_owned(), DataType::Utf8]),
-                    (DataType::Dictionary(_, value_type), DataType::LargeUtf8 | DataType::Utf8View | DataType::Utf8)  => match **value_type {
-                        DataType::LargeUtf8 | DataType::Utf8View | DataType::Utf8 | DataType::Null | DataType::Binary => Ok(vec![*value_type.clone(), second.to_owned()]),
-                        _ => plan_err!("The STRPOS/INSTR/POSITION function can only accept strings, but got {:?}.", **value_type),
-                    },
-                    _ => plan_err!("The STRPOS/INSTR/POSITION function can only accept strings, but got {:?}.", arg_types)
-                }
-            },
-            _ => plan_err!("The STRPOS/INSTR/POSITION function can only accept strings, but got {:?}", arg_types)
-        }
-    }
 }
 
 fn strpos(args: &[ArrayRef]) -> Result<ArrayRef> {

datafusion/sqllogictest/test_files/functions.slt

@@ -553,6 +553,16 @@ SELECT strpos(arrow_cast('helloworld', 'Dictionary(Int32, Utf8)'), 'world')
 ----
 6
 
+query I
+SELECT strpos('helloworld', NULL)
+----
+NULL
+
+query I
+SELECT strpos(arrow_cast('helloworld', 'Dictionary(Int32, Utf8)'), NULL)
+----
+NULL
+
 statement ok
 CREATE TABLE products (
 product_id INT PRIMARY KEY,

datafusion/sqllogictest/test_files/scalar.slt

@@ -1907,8 +1907,10 @@ select position('' in '')
 1
 
 
-query error POSITION function can only accept strings
+query I
 select position(1 in 1)
+----
+1
 
 
 query I