(arrow-rs) branch main updated: Fix casting floats to Decimal64 (#8363)

[alamb]

This is an automated email from the ASF dual-hosted git repository.

alamb pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow-rs.git


The following commit(s) were added to refs/heads/main by this push:
     new 769643206f Fix casting floats to Decimal64 (#8363)
769643206f is described below

commit 769643206fa230a41d60cf3a9044a073b91f431e
Author: Adam Gutglick <a...@spiraldb.com>
AuthorDate: Tue Sep 16 19:39:42 2025 +0100

    Fix casting floats to Decimal64 (#8363)
    
    # Which issue does this PR close?
    Closes #8362
    
    
    # Rationale for this change
    Fixes casting codepaths that currently fail.
    
    # What changes are included in this PR?
    
    
    # Are these changes tested?
    
    yes
    
    If tests are not included in your PR, please explain why (for example,
    are they covered by existing tests)?
    
    # Are there any user-facing changes?
    
    Code should now behave as expected
    
    ---------
    
    Co-authored-by: Andrew Lamb <and...@nerdnetworks.org>
---
 arrow-cast/src/cast/decimal.rs |  4 +++-
 arrow-cast/src/cast/mod.rs     | 29 +++++++++++++++++++++++++++++
 parquet-testing                |  2 +-
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/arrow-cast/src/cast/decimal.rs b/arrow-cast/src/cast/decimal.rs
index 00bfc57e12..095e312748 100644
--- a/arrow-cast/src/cast/decimal.rs
+++ b/arrow-cast/src/cast/decimal.rs
@@ -81,7 +81,9 @@ impl DecimalCast for i64 {
     }
 
     fn from_f64(n: f64) -> Option<Self> {
-        n.to_i64()
+        // Call implementation explicitly otherwise this resolves to `to_i64`
+        // in arrow-buffer that behaves differently.
+        num::traits::ToPrimitive::to_i64(&n)
     }
 }
 
diff --git a/arrow-cast/src/cast/mod.rs b/arrow-cast/src/cast/mod.rs
index 117ad10b11..fc241bea48 100644
--- a/arrow-cast/src/cast/mod.rs
+++ b/arrow-cast/src/cast/mod.rs
@@ -3101,6 +3101,35 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_cast_floating_to_decimals() {
+        for output_type in [
+            DataType::Decimal32(9, 3),
+            DataType::Decimal64(9, 3),
+            DataType::Decimal128(9, 3),
+            DataType::Decimal256(9, 3),
+        ] {
+            let input_type = DataType::Float64;
+            assert!(can_cast_types(&input_type, &output_type));
+
+            let array = vec![Some(1.1_f64)];
+            let array = PrimitiveArray::<Float64Type>::from_iter(array);
+            let result = cast_with_options(
+                &array,
+                &output_type,
+                &CastOptions {
+                    safe: false,
+                    format_options: FormatOptions::default(),
+                },
+            );
+            assert!(
+                result.is_ok(),
+                "Failed to cast to {output_type} with: {}",
+                result.unwrap_err()
+            );
+        }
+    }
+
     #[test]
     fn test_cast_decimal128_to_decimal128_overflow() {
         let input_type = DataType::Decimal128(38, 3);
diff --git a/parquet-testing b/parquet-testing
index 5cbfc43d48..a3d96a65e1 160000
--- a/parquet-testing
+++ b/parquet-testing
@@ -1 +1 @@
-Subproject commit 5cbfc43d488c9c8404a1a7088cca400ae095b831
+Subproject commit a3d96a65e11e2bbca7d22a894e8313ede90a33a3