ZhangHuiGui opened a new issue, #40126:
URL: https://github.com/apache/arrow/issues/40126
### Describe the bug, including details regarding any error messages,
version, and platform.
## How to reproduce
Add two different precision and scale decimal arrays through expression.
```c
auto expr = arrow::compute::call("add", {arrow::compute::field_ref("l1"),
arrow::compute::field_ref("r1")});
auto s1 = arrow::schema({arrow::field("l1", arrow::decimal128(30, 3)),
arrow::field("r1", arrow::decimal128(20, 9))});
ASSERT_OK_AND_ASSIGN(expr, expr.Bind(*s1));
auto b = arrow::RecordBatchFromJSON(s1, R"([
["1.000", "-1.000000000"],
["-123456789012345678901234567.890", "12345678901.234567890"]
])");
ASSERT_OK_AND_ASSIGN(auto input, arrow::compute::MakeExecBatch(*s1, b));
ASSERT_OK_AND_ASSIGN(auto res_dat,
arrow::compute::ExecuteScalarExpression(expr,
input)); // crash
```
The test will crash at below function's `DCHECK_EQ`.
```c
Result<TypeHolder> ResolveDecimalAdditionOrSubtractionOutput(
KernelContext*, const std::vector<TypeHolder>& types) {
return ResolveDecimalBinaryOperationOutput(
types, [](int32_t p1, int32_t s1, int32_t p2, int32_t s2) {
DCHECK_EQ(s1, s2);
const int32_t scale = s1;
const int32_t precision = std::max(p1 - s1, p2 - s2) + scale + 1;
return std::make_pair(precision, scale);
});
}
The `CallFunction` is correct.
```
## Reason
The expression's bind function will skip `DispatchBest` in
`BindNonRecursive`. Because `DispatchExact` will return ok and skip the
`DispatchBest` which overrided by `ArithmeticFunction`.
```c
// First try and bind exactly
Result<const Kernel*> maybe_exact_match =
call.function->DispatchExact(types);
if (maybe_exact_match.ok()) {
call.kernel = *maybe_exact_match;
}
```
So the implicit cast in `ArithmeticFunction::DispatchBest` for decimal will
be skipped.
But the logic is correct in `CallFunction` which will call `DispatchBest`
first.
If we want to let user do cast by theirselves in expression call, we should
return an error if we checked current situation? Or return not-ok in
DispatchExact for decimal special case?
### Component(s)
C++
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