Refactor log() signature to use coercion API + fixes (#18519)

## Which issue does this PR close?

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Part of #14763 and #14760

## Rationale for this change

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in the issue then this section is not needed.
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Current `log()` signature has some drawbacks:


https://github.com/apache/datafusion/blob/a5eb9121ccf802dda547897155403b08a4fbf774/datafusion/functions/src/math/log.rs#L78-L105

- A bit nasty to look at: mixes numeric with exact float/int with exact
decimal (of exact precision and scale)
- Can't accommodate arbitrary decimals of any precision/scale (this is
true for other functions too)

Aim of this PR is to refactor it to use the coercion API, uplifting the
API where necessary to make this possible. This simplifies the signature
in code, whilst not losing flexibility.

Also other minor refactors are included to log.

## What changes are included in this PR?

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PR.
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New `TypeSignatureClass` variants: Float, Decimal & Numeric

Refactor `log()` signature to be more in line with it's supported
implementations.

Fix issue in `log()` where `ColumnarValue::Scalar`s were being lost as
`ColumnarValue::Array`s for the base.

Support null propagation in `simplify()` for `log()`.

~~Fix issue with `calculate_binary_math` where it wasn't casting
scalars.~~

## Are these changes tested?

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Added new tests.

- Tests for float16, decimal32, decimal64, decimals with different
scales/precisions
- Test for null propagation (ensure use array input to avoid function
inlining)

## Are there any user-facing changes?

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No.

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Author: Jefffrey

datafusion/common/src/scalar/mod.rs

@@ -1734,7 +1734,7 @@ impl ScalarValue {
                 ) {
                     return _internal_err!("Invalid precision and scale {err}");
                 }
-                if *scale <= 0 {
+                if *scale < 0 {
                     return _internal_err!("Negative scale is not supported");
                 }
                 match 10_i32.checked_pow((*scale + 1) as u32) {
@@ -1750,7 +1750,7 @@ impl ScalarValue {
                 ) {
                     return _internal_err!("Invalid precision and scale {err}");
                 }
-                if *scale <= 0 {
+                if *scale < 0 {
                     return _internal_err!("Negative scale is not supported");
                 }
                 match i64::from(10).checked_pow((*scale + 1) as u32) {
@@ -4407,6 +4407,7 @@ macro_rules! impl_scalar {
 
 impl_scalar!(f64, Float64);
 impl_scalar!(f32, Float32);
+impl_scalar!(f16, Float16);
 impl_scalar!(i8, Int8);
 impl_scalar!(i16, Int16);
 impl_scalar!(i32, Int32);
@@ -4563,6 +4564,7 @@ impl_try_from!(UInt8, u8);
 impl_try_from!(UInt16, u16);
 impl_try_from!(UInt32, u32);
 impl_try_from!(UInt64, u64);
+impl_try_from!(Float16, f16);
 impl_try_from!(Float32, f32);
 impl_try_from!(Float64, f64);
 impl_try_from!(Boolean, bool);

datafusion/common/src/types/native.rs

@@ -430,22 +430,7 @@ impl From<DataType> for NativeType {
 impl NativeType {
     #[inline]
     pub fn is_numeric(&self) -> bool {
-        use NativeType::*;
-        matches!(
-            self,
-            UInt8
-                | UInt16
-                | UInt32
-                | UInt64
-                | Int8
-                | Int16
-                | Int32
-                | Int64
-                | Float16
-                | Float32
-                | Float64
-                | Decimal(_, _)
-        )
+        self.is_integer() || self.is_float() || self.is_decimal()
     }
 
     #[inline]
@@ -491,4 +476,14 @@ impl NativeType {
     pub fn is_null(&self) -> bool {
         matches!(self, NativeType::Null)
     }
+
+    #[inline]
+    pub fn is_decimal(&self) -> bool {
+        matches!(self, Self::Decimal(_, _))
+    }
+
+    #[inline]
+    pub fn is_float(&self) -> bool {
+        matches!(self, Self::Float16 | Self::Float32 | Self::Float64)
+    }
 }

datafusion/expr-common/src/signature.rs

@@ -21,7 +21,7 @@ use std::fmt::Display;
 use std::hash::Hash;
 
 use crate::type_coercion::aggregates::NUMERICS;
-use arrow::datatypes::{DataType, IntervalUnit, TimeUnit};
+use arrow::datatypes::{DataType, Decimal128Type, DecimalType, IntervalUnit, TimeUnit};
 use datafusion_common::types::{LogicalType, LogicalTypeRef, NativeType};
 use datafusion_common::utils::ListCoercion;
 use datafusion_common::{internal_err, plan_err, Result};
@@ -333,9 +333,10 @@ pub enum TypeSignatureClass {
     Interval,
     Duration,
     Native(LogicalTypeRef),
-    // TODO:
-    // Numeric
     Integer,
+    Float,
+    Decimal,
+    Numeric,
     /// Encompasses both the native Binary as well as arbitrarily sized FixedSizeBinary types
     Binary,
 }
@@ -378,6 +379,13 @@ impl TypeSignatureClass {
             TypeSignatureClass::Binary => {
                 vec![DataType::Binary]
             }
+            TypeSignatureClass::Decimal => vec![Decimal128Type::DEFAULT_TYPE],
+            TypeSignatureClass::Float => vec![DataType::Float64],
+            TypeSignatureClass::Numeric => vec![
+                DataType::Float64,
+                DataType::Int64,
+                Decimal128Type::DEFAULT_TYPE,
+            ],
         }
     }
 
@@ -395,6 +403,9 @@ impl TypeSignatureClass {
             TypeSignatureClass::Duration if logical_type.is_duration() => true,
             TypeSignatureClass::Integer if logical_type.is_integer() => true,
             TypeSignatureClass::Binary if logical_type.is_binary() => true,
+            TypeSignatureClass::Decimal if logical_type.is_decimal() => true,
+            TypeSignatureClass::Float if logical_type.is_float() => true,
+            TypeSignatureClass::Numeric if logical_type.is_numeric() => true,
             _ => false,
         }
     }
@@ -428,6 +439,15 @@ impl TypeSignatureClass {
             TypeSignatureClass::Binary if native_type.is_binary() => {
                 Ok(origin_type.to_owned())
             }
+            TypeSignatureClass::Decimal if native_type.is_decimal() => {
+                Ok(origin_type.to_owned())
+            }
+            TypeSignatureClass::Float if native_type.is_float() => {
+                Ok(origin_type.to_owned())
+            }
+            TypeSignatureClass::Numeric if native_type.is_numeric() => {
+                Ok(origin_type.to_owned())
+            }
             _ if native_type.is_null() => Ok(origin_type.to_owned()),
             _ => internal_err!("May miss the matching logic in `matches_native_type`"),
         }