jruby · headius · Jan 30, 2026 · Jan 30, 2026 · Jan 30, 2026
diff --git a/core/src/main/java/org/jruby/RubyModule.java b/core/src/main/java/org/jruby/RubyModule.java
@@ -1938,9 +1938,7 @@ public final void addMethodInternal(ThreadContext context, String name, DynamicM
             putMethod(context, name, method);
         }
 
-        synchronized (getRuntime().getHierarchyLock()) {
-            invalidateCacheDescendants(context);
-        }
+        invalidateMethodCache(context);
     }
 
     public void removeMethod(ThreadContext context, String id) {
@@ -2376,6 +2374,17 @@ public void invalidateCacheDescendants(ThreadContext context) {
         methodInvalidator.invalidateAll(invalidators);
     }
 
+    /**
+     * Invalidate the method cache of this class and all descendants under lock.
+     *
+     * @param context
+     */
+    public void invalidateMethodCache(ThreadContext context) {
+        synchronized (getRuntime().getHierarchyLock()) {
+            invalidateCacheDescendants(context);
+        }
+    }
+
     public static class InvalidatorList<T> extends ArrayList<T> implements RubyClass.BiConsumerIgnoresSecond<RubyClass> {
         public InvalidatorList(int size) {
             super(size);

diff --git a/core/src/main/java/org/jruby/anno/AnnotationBinder.java b/core/src/main/java/org/jruby/anno/AnnotationBinder.java
@@ -242,6 +242,15 @@ public void processType(TypeElement cd) {
             out.print(classAndSubs.stream().map(s -> quote(s)).collect(Collectors.joining(", ")));
             mappings.forEach((javaName, rubyName) -> out.print(", " + quote(javaName) + ", " + quote(rubyName) + ""));
             out.println(");");
+
+            // invalidateMethodCache if not booting core
+            out.println("        if (!core) {");
+            out.println("            cls.invalidateMethodCache(context);");
+            if (hasMeta || hasModule) {
+                out.println("            singletonClass.invalidateMethodCache(context);");
+            }
+            out.println("        }");
+
             out.println("    }");
 
             // write out a static initializer for frame names, so it only fires once

diff --git a/core/src/test/java/org/jruby/test/TestRubyModule.java b/core/src/test/java/org/jruby/test/TestRubyModule.java
@@ -0,0 +1,46 @@
+package org.jruby.test;
+
+import org.jruby.Ruby;
+import org.jruby.api.Create;
+import org.jruby.exceptions.NoMethodError;
+import org.jruby.ext.bigdecimal.BigDecimalLibrary;
+import org.jruby.ext.bigdecimal.RubyBigDecimal;
+
+public class TestRubyModule extends junit.framework.TestCase {
+
+    Ruby runtime;
+
+    public TestRubyModule(String testName) {
+        super(testName);
+    }
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        runtime = Ruby.newInstance();
+
+    }
+
+    @Override
+    protected void tearDown() throws Exception {
+        super.tearDown();
+        runtime.tearDown();
+    }
+
+    public void testKernelBigDecimalMethodMissingCache() throws Throwable {
+        var context = runtime.getCurrentContext();
+
+        try {
+            runtime.getObject().callMethod("BigDecimal", Create.newString(context, "1.0"));
+        } catch (NoMethodError nme) {
+            assertTrue(nme.getMessage().contains("BigDecimal"));
+        }
+
+        new BigDecimalLibrary().load(runtime, false);
+
+        var result = runtime.getObject().callMethod("BigDecimal", Create.newString(context, "1.0"));
+
+        assertTrue(result instanceof RubyBigDecimal);
+        assertEquals(1.0, result.convertToFloat().getValue());
+    }
+}