From 7648fad723ed78d59a7ad5aa4d0521381a98865b Mon Sep 17 00:00:00 2001
From: Vasiliy Mikhailov <vasiliy.mikhailov@gmail.com>
Date: Mon, 22 Jun 2026 10:27:16 +0300
Subject: [PATCH] Rethrow Error from @PostConstruct method instead of wrapping
 it in RuntimeException

PostConstructAdapterFactory rethrows a RuntimeException cause as-is but wraps
everything else. An Error thrown by the @PostConstruct method (AssertionError,
OutOfMemoryError, ...) is unchecked like RuntimeException and should propagate
as-is, not be smothered in a RuntimeException. Rethrow Error the same way.
Adds a regression test.
---
 .../PostConstructAdapterFactory.java          |  2 ++
 .../PostConstructAdapterFactoryTest.java      | 31 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/extras/src/main/java/com/google/gson/typeadapters/PostConstructAdapterFactory.java b/extras/src/main/java/com/google/gson/typeadapters/PostConstructAdapterFactory.java
index 924a9089ff..cc731085f5 100644
--- a/extras/src/main/java/com/google/gson/typeadapters/PostConstructAdapterFactory.java
+++ b/extras/src/main/java/com/google/gson/typeadapters/PostConstructAdapterFactory.java
@@ -65,6 +65,8 @@ public T read(JsonReader in) throws IOException {
         } catch (InvocationTargetException e) {
           if (e.getCause() instanceof RuntimeException) {
             throw (RuntimeException) e.getCause();
+          } else if (e.getCause() instanceof Error) {
+            throw (Error) e.getCause();
           }
           throw new RuntimeException(e.getCause());
         }
diff --git a/extras/src/test/java/com/google/gson/typeadapters/PostConstructAdapterFactoryTest.java b/extras/src/test/java/com/google/gson/typeadapters/PostConstructAdapterFactoryTest.java
index a46fa3089b..943bd11798 100644
--- a/extras/src/test/java/com/google/gson/typeadapters/PostConstructAdapterFactoryTest.java
+++ b/extras/src/test/java/com/google/gson/typeadapters/PostConstructAdapterFactoryTest.java
@@ -95,6 +95,37 @@ public boolean equals(Object o) {
     }
   }
 
+  @Test
+  public void testErrorFromPostConstructPropagatesAsError() {
+    Gson gson =
+        new GsonBuilder().registerTypeAdapterFactory(new PostConstructAdapterFactory()).create();
+
+    CustomTestError thrown =
+        assertThrows(
+            CustomTestError.class, () -> gson.fromJson("{\"value\": 1}", ErrorThrowingClass.class));
+
+    assertThat(thrown).hasMessageThat().isEqualTo("error from post-construct");
+  }
+
+  static class ErrorThrowingClass {
+    public int value;
+
+    @PostConstruct
+    private void init() {
+      throw new CustomTestError("error from post-construct");
+    }
+  }
+
+  // A dedicated Error subclass so the test does not rely on a JDK Error type (e.g. AssertionError,
+  // which Gson re-tags with a version prefix) and is not confused with a meaningful JVM error.
+  private static final class CustomTestError extends Error {
+    private static final long serialVersionUID = 1L;
+
+    CustomTestError(String message) {
+      super(message);
+    }
+  }
+
   @SuppressWarnings({"overrides", "EqualsHashCode"}) // for missing hashCode() override
   static class MultipleSandwiches {
     public List<Sandwich> sandwiches;