From 14849dbd69a782cdfbac3f528e42bd3065310dc7 Mon Sep 17 00:00:00 2001
From: JParams <26733487+jparams@users.noreply.github.com>
Date: Fri, 13 Mar 2026 14:10:33 +0000
Subject: [PATCH] Fix generic type inference in NumberExpression sum()

---
 .../core/types/dsl/NumberExpression.java      | 36 ++++++++++++++++---
 .../core/types/dsl/NumberExpressionTest.java  | 24 +++++++++++++
 2 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/querydsl-core/src/main/java/com/querydsl/core/types/dsl/NumberExpression.java b/querydsl-core/src/main/java/com/querydsl/core/types/dsl/NumberExpression.java
index 022c0dc287..b8a570e031 100644
--- a/querydsl-core/src/main/java/com/querydsl/core/types/dsl/NumberExpression.java
+++ b/querydsl-core/src/main/java/com/querydsl/core/types/dsl/NumberExpression.java
@@ -16,6 +16,8 @@
 import com.querydsl.core.types.*;
 import com.querydsl.core.types.Ops.MathOps;
 import com.querydsl.core.util.MathUtils;
+import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;
 import org.jetbrains.annotations.Nullable;
@@ -747,6 +749,14 @@ public <N extends Number & Comparable<?>> NumberExpression<T> subtract(N right)
     return Expressions.numberOperation(getType(), Ops.SUB, mixin, ConstantImpl.create(right));
   }
 
+  @SuppressWarnings("unchecked")
+  private <P extends Number & Comparable<?>> NumberExpression<P> sum(Class<P> clazz) {
+    if (sum == null) {
+      sum = (NumberExpression<T>) Expressions.numberOperation(clazz, Ops.AggOps.SUM_AGG, mixin);
+    }
+    return (NumberExpression<P>) sum;
+  }
+
   /**
    * Create a {@code sum(this)} expression
    *
@@ -754,11 +764,29 @@ public <N extends Number & Comparable<?>> NumberExpression<T> subtract(N right)
    *
    * @return sum(this)
    */
+  @SuppressWarnings("unchecked")
   public NumberExpression<T> sum() {
-    if (sum == null) {
-      sum = Expressions.numberOperation(getType(), Ops.AggOps.SUM_AGG, mixin);
-    }
-    return sum;
+    return sum((Class<T>) getType());
+  }
+
+  /** {@link Float} {@link Double} are mapped to sumDouble. */
+  public NumberExpression<Double> sumDouble() {
+    return sum(Double.class);
+  }
+
+  /** {@link Byte} {@link Short} {@link Integer} {@link Long} are mapped to sumLong. */
+  public NumberExpression<Long> sumLong() {
+    return sum(Long.class);
+  }
+
+  /** {@link java.math.BigDecimal} are mapped to sumBigDecimal. */
+  public NumberExpression<BigDecimal> sumBigDecimal() {
+    return sum(BigDecimal.class);
+  }
+
+  /** {@link java.math.BigInteger} are mapped to sumBigInteger. */
+  public NumberExpression<BigInteger> sumBigInteger() {
+    return sum(BigInteger.class);
   }
 
   @Override
diff --git a/querydsl-core/src/test/java/com/querydsl/core/types/dsl/NumberExpressionTest.java b/querydsl-core/src/test/java/com/querydsl/core/types/dsl/NumberExpressionTest.java
index 3414f975f8..704207fbd6 100644
--- a/querydsl-core/src/test/java/com/querydsl/core/types/dsl/NumberExpressionTest.java
+++ b/querydsl-core/src/test/java/com/querydsl/core/types/dsl/NumberExpressionTest.java
@@ -15,6 +15,9 @@
 
 import static org.junit.Assert.assertEquals;
 
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
 import org.junit.Test;
 
 public class NumberExpressionTest {
@@ -30,4 +33,25 @@ public void between_start_given() {
   public void between_end_given() {
     assertEquals(intPath.loe(3L), intPath.between(null, 3L));
   }
+
+  @Test
+  public void sumBigDecimal_has_bigDecimal_type() {
+    assertEquals(BigDecimal.class, intPath.sumBigDecimal().getType());
+  }
+
+  @Test
+  public void sumBigInteger_has_bigInteger_type() {
+    assertEquals(BigInteger.class, intPath.sumBigInteger().getType());
+  }
+
+  @Test
+  public void sumDouble_has_double_type() {
+    assertEquals(Double.class, intPath.sumDouble().getType());
+  }
+
+  @Test
+  public void sumLong_has_long_type() {
+    assertEquals(Long.class, intPath.sumLong().getType());
+  }
+
 }