[GitHub] [arrow-rs] crepererum commented on a diff in pull request #2902: add `Array::as_any_arc`

[GitBox <gi...@apache.org>]

crepererum commented on code in PR #2902:
URL: https://github.com/apache/arrow-rs/pull/2902#discussion_r1003454609


##########
arrow-array/src/array/mod.rs:
##########
@@ -88,6 +88,31 @@ pub trait Array: std::fmt::Debug + Send + Sync {
     /// ```
     fn as_any(&self) -> &dyn Any;
 
+    /// Returns the array as [`Any`](std::any::Any) wrapped into an [`Arc`] so that it can be
+    /// downcasted to a specific implementation without the need for an unsized reference. This is helpful if you want
+    /// to return a concrete array type.
+    /// 
+    /// Note that this conversion may not be possible for all types due to the `'static` constraint.
+    ///
+    /// # Example:
+    ///
+    /// ```
+    /// # use std::sync::Arc;
+    /// # use arrow_array::{Int32Array, RecordBatch};
+    /// # use arrow_schema::{Schema, Field, DataType, ArrowError};
+    ///
+    /// let id = Int32Array::from(vec![1, 2, 3, 4, 5]);
+    /// let batch = RecordBatch::try_new(
+    ///     Arc::new(Schema::new(vec![Field::new("id", DataType::Int32, false)])),
+    ///     vec![Arc::new(id)]
+    /// ).unwrap();
+    ///
+    /// let int32array = Arc::downcast::<Int32Array>(
+    ///     Arc::clone(batch.column(0)).as_any_arc().expect("Failed to create static Arc")
+    /// ).expect("Failed to downcast");

Review Comment:
   Adding a helpers sounds great.
   
   Regarding privacy: do we consider `Array` to be a sealed trait (because this would be the implication)? Currently users can implement their own `Array` types if they want.



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