From 100e9b757c30a3a97fb6b09351bfb56bbf27d1c9 Mon Sep 17 00:00:00 2001
From: sriram <sriramsundararajan83@gmail.com>
Date: Tue, 25 Nov 2025 22:35:13 +0530
Subject: [PATCH 1/2] deprecate AggregateUDF::is_nullable

---
 datafusion/expr/src/expr_schema.rs        |  5 +++--
 datafusion/expr/src/udaf.rs               | 11 ++++++++++-
 datafusion/physical-expr/src/aggregate.rs |  2 +-
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/datafusion/expr/src/expr_schema.rs b/datafusion/expr/src/expr_schema.rs
index 94f5b0480b65..725d7b0a3f8e 100644
--- a/datafusion/expr/src/expr_schema.rs
+++ b/datafusion/expr/src/expr_schema.rs
@@ -353,8 +353,9 @@ impl ExprSchemable for Expr {
                 let (_, nullable) = self.data_type_and_nullable(input_schema)?;
                 Ok(nullable)
             }
-            Expr::AggregateFunction(AggregateFunction { func, .. }) => {
-                Ok(func.is_nullable())
+            Expr::AggregateFunction(_) => {
+                let (_, nullable) = self.data_type_and_nullable(input_schema)?;
+                Ok(nullable)
             }
             Expr::WindowFunction(window_function) => self
                 .data_type_and_nullable_with_window_function(
diff --git a/datafusion/expr/src/udaf.rs b/datafusion/expr/src/udaf.rs
index e2ae697deedf..c756ee299832 100644
--- a/datafusion/expr/src/udaf.rs
+++ b/datafusion/expr/src/udaf.rs
@@ -209,6 +209,7 @@ impl AggregateUDF {
     }
 
     pub fn is_nullable(&self) -> bool {
+        #[allow(deprecated)]
         self.inner.is_nullable()
     }
 
@@ -532,6 +533,10 @@ pub trait AggregateUDFImpl: Debug + DynEq + DynHash + Send + Sync {
     /// For example, aggregate functions like `COUNT` always return a non null value
     /// but others like `MIN` will return `NULL` if there is nullable input.
     /// Note that if the function is declared as *not* nullable, make sure the [`AggregateUDFImpl::default_value`] is `non-null`
+    #[deprecated(
+        since = "51.0.0",
+        note = "Use `return_field` instead with return_field.is_nullable()."
+    )]
     fn is_nullable(&self) -> bool {
         true
     }
@@ -1100,7 +1105,10 @@ pub fn udaf_default_return_field<F: AggregateUDFImpl + ?Sized>(
     Ok(Arc::new(Field::new(
         func.name(),
         data_type,
-        func.is_nullable(),
+        #[allow(deprecated)]
+        {
+            func.is_nullable()
+        },
     )))
 }
 
@@ -1247,6 +1255,7 @@ impl AggregateUDFImpl for AliasedAggregateUDFImpl {
     }
 
     fn is_nullable(&self) -> bool {
+        #[allow(deprecated)]
         self.inner.is_nullable()
     }
 
diff --git a/datafusion/physical-expr/src/aggregate.rs b/datafusion/physical-expr/src/aggregate.rs
index ae5a4a855947..aee329ab4b43 100644
--- a/datafusion/physical-expr/src/aggregate.rs
+++ b/datafusion/physical-expr/src/aggregate.rs
@@ -222,7 +222,7 @@ impl AggregateExprBuilder {
         )?;
 
         let return_field = fun.return_field(&input_exprs_fields)?;
-        let is_nullable = fun.is_nullable();
+        let is_nullable = return_field.is_nullable();
         let name = match alias {
             None => {
                 return internal_err!(

From 2aeedc8bb127db758bb26b8afa393d5eb39dd93a Mon Sep 17 00:00:00 2001
From: sriram <sriramsundararajan83@gmail.com>
Date: Wed, 26 Nov 2025 22:36:42 +0530
Subject: [PATCH 2/2] add missed out [#expect(deprecated)] assertions

---
 datafusion/expr/src/udaf.rs    | 12 ++++++++----
 datafusion/ffi/src/udaf/mod.rs |  1 +
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/datafusion/expr/src/udaf.rs b/datafusion/expr/src/udaf.rs
index c756ee299832..91437d60a250 100644
--- a/datafusion/expr/src/udaf.rs
+++ b/datafusion/expr/src/udaf.rs
@@ -208,8 +208,12 @@ impl AggregateUDF {
         self.inner.window_function_display_name(params)
     }
 
+    #[deprecated(
+        since = "52.0.0",
+        note = "Use `return_field` instead with return_field.is_nullable()."
+    )]
     pub fn is_nullable(&self) -> bool {
-        #[allow(deprecated)]
+        #[expect(deprecated)]
         self.inner.is_nullable()
     }
 
@@ -534,7 +538,7 @@ pub trait AggregateUDFImpl: Debug + DynEq + DynHash + Send + Sync {
     /// but others like `MIN` will return `NULL` if there is nullable input.
     /// Note that if the function is declared as *not* nullable, make sure the [`AggregateUDFImpl::default_value`] is `non-null`
     #[deprecated(
-        since = "51.0.0",
+        since = "52.0.0",
         note = "Use `return_field` instead with return_field.is_nullable()."
     )]
     fn is_nullable(&self) -> bool {
@@ -1105,7 +1109,7 @@ pub fn udaf_default_return_field<F: AggregateUDFImpl + ?Sized>(
     Ok(Arc::new(Field::new(
         func.name(),
         data_type,
-        #[allow(deprecated)]
+        #[expect(deprecated)]
         {
             func.is_nullable()
         },
@@ -1255,7 +1259,7 @@ impl AggregateUDFImpl for AliasedAggregateUDFImpl {
     }
 
     fn is_nullable(&self) -> bool {
-        #[allow(deprecated)]
+        #[expect(deprecated)]
         self.inner.is_nullable()
     }
 
diff --git a/datafusion/ffi/src/udaf/mod.rs b/datafusion/ffi/src/udaf/mod.rs
index a416753c371b..d254561fba34 100644
--- a/datafusion/ffi/src/udaf/mod.rs
+++ b/datafusion/ffi/src/udaf/mod.rs
@@ -344,6 +344,7 @@ impl From<Arc<AggregateUDF>> for FFI_AggregateUDF {
     fn from(udaf: Arc<AggregateUDF>) -> Self {
         let name = udaf.name().into();
         let aliases = udaf.aliases().iter().map(|a| a.to_owned().into()).collect();
+        #[expect(deprecated)]
         let is_nullable = udaf.is_nullable();
         let volatility = udaf.signature().volatility.into();