From 71bd8df49bd44d6d4630f9763364ce360cd9337b Mon Sep 17 00:00:00 2001
From: jdymitarai <o10040115@gmail.com>
Date: Fri, 11 Sep 2026 22:14:12 +0800
Subject: [PATCH] Throw JsonSyntaxException for null element in primitive array

---
 .../gson/internal/bind/ArrayTypeAdapter.java  |  8 +++
 .../com/google/gson/functional/ArrayTest.java | 53 +++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/gson/src/main/java/com/google/gson/internal/bind/ArrayTypeAdapter.java b/gson/src/main/java/com/google/gson/internal/bind/ArrayTypeAdapter.java
index 50efa418c0..664a767a1a 100644
--- a/gson/src/main/java/com/google/gson/internal/bind/ArrayTypeAdapter.java
+++ b/gson/src/main/java/com/google/gson/internal/bind/ArrayTypeAdapter.java
@@ -17,6 +17,7 @@
 package com.google.gson.internal.bind;
 
 import com.google.gson.Gson;
+import com.google.gson.JsonSyntaxException;
 import com.google.gson.TypeAdapter;
 import com.google.gson.TypeAdapterFactory;
 import com.google.gson.internal.GsonTypes;
@@ -73,6 +74,13 @@ public Object read(JsonReader in) throws IOException {
     in.beginArray();
     while (in.hasNext()) {
       E instance = componentTypeAdapter.read(in);
+      if (componentType.isPrimitive() && instance == null) {
+        throw new JsonSyntaxException(
+            "null is not a valid "
+                + componentType.getName()
+                + "[] element; at path "
+                + in.getPreviousPath());
+      }
       list.add(instance);
     }
     in.endArray();
diff --git a/gson/src/test/java/com/google/gson/functional/ArrayTest.java b/gson/src/test/java/com/google/gson/functional/ArrayTest.java
index b8a4e3a069..3939f2a52f 100644
--- a/gson/src/test/java/com/google/gson/functional/ArrayTest.java
+++ b/gson/src/test/java/com/google/gson/functional/ArrayTest.java
@@ -22,6 +22,7 @@
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
+import com.google.gson.JsonSyntaxException;
 import com.google.gson.common.TestTypes.BagOfPrimitives;
 import com.google.gson.common.TestTypes.ClassWithObjects;
 import com.google.gson.reflect.TypeToken;
@@ -101,6 +102,58 @@ public void testNullsInArrayDeserialization() {
     assertThat(target).asList().containsAnyIn(expected);
   }
 
+  @Test
+  public void testNullsInPrimitiveArrayDeserialization() {
+    var e = assertThrows(JsonSyntaxException.class, () -> gson.fromJson("[1,null,3]", int[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid int[] element; at path $[1]");
+
+    e =
+        assertThrows(
+            JsonSyntaxException.class, () -> gson.fromJson("[true,null,false]", boolean[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid boolean[] element; at path $[1]");
+
+    e =
+        assertThrows(
+            JsonSyntaxException.class, () -> gson.fromJson("[1.0,null,2.0]", double[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid double[] element; at path $[1]");
+
+    e = assertThrows(JsonSyntaxException.class, () -> gson.fromJson("[1,null,2]", long[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid long[] element; at path $[1]");
+
+    e =
+        assertThrows(
+            JsonSyntaxException.class, () -> gson.fromJson("['a',null,'b']", char[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid char[] element; at path $[1]");
+
+    e = assertThrows(JsonSyntaxException.class, () -> gson.fromJson("[1,null,2]", byte[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid byte[] element; at path $[1]");
+
+    e = assertThrows(JsonSyntaxException.class, () -> gson.fromJson("[1,null,2]", short[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid short[] element; at path $[1]");
+
+    e =
+        assertThrows(
+            JsonSyntaxException.class, () -> gson.fromJson("[1.0,null,2.0]", float[].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid float[] element; at path $[1]");
+
+    // Multidimensional array: null inner element
+    e =
+        assertThrows(
+            JsonSyntaxException.class, () -> gson.fromJson("[[1,null],[2,3]]", int[][].class));
+    assertThat(e).hasMessageThat().isEqualTo("null is not a valid int[] element; at path $[0][1]");
+  }
+
+  @Test
+  public void testNullsInBoxedAndMultidimensionalArray() {
+    Integer[] boxed = gson.fromJson("[1,null,3]", Integer[].class);
+    assertThat(boxed).asList().containsExactly(1, null, 3).inOrder();
+
+    int[][] multi = gson.fromJson("[[1,2],null]", int[][].class);
+    assertThat(multi).hasLength(2);
+    assertThat(multi[0]).isEqualTo(new int[] {1, 2});
+    assertThat(multi[1]).isNull();
+  }
+
   @Test
   public void testSingleNullInArraySerialization() {
     BagOfPrimitives[] array = new BagOfPrimitives[1];