From e14e9982a56818f4ae919152de8acbef7ed8abba Mon Sep 17 00:00:00 2001
From: Chad Wilson <29788154+chadlwilson@users.noreply.github.com>
Date: Sat, 23 May 2026 14:54:15 +0800
Subject: [PATCH] test: add temporary workaround to ensure we can see
 backtraces

---
 .../java_throwable_backtrace_locations.rb         | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 integration/rails7_test/src/main/ruby/config/initializers/java_throwable_backtrace_locations.rb

diff --git a/integration/rails7_test/src/main/ruby/config/initializers/java_throwable_backtrace_locations.rb b/integration/rails7_test/src/main/ruby/config/initializers/java_throwable_backtrace_locations.rb
new file mode 100644
index 00000000..0b7b3894
--- /dev/null
+++ b/integration/rails7_test/src/main/ruby/config/initializers/java_throwable_backtrace_locations.rb
@@ -0,0 +1,15 @@
+if defined?(Java)
+  Java::JavaLang::Throwable.class_eval do
+    # Ruby's #backtrace_locations isn't defined on Java Throwables. Rails 7.2's
+    # ActionDispatch::ExceptionWrapper#build_backtrace assumes it exists, and the
+    # NoMethodError it raises masks the real underlying Java exception (see actionpack/lib/action_dispatch/middleware/exception_wrapper.rb:269)
+    # https://github.com/jruby/jruby/blob/2e078cd889f0a025ff607d9919f3dfdf9bf24390/core/src/main/java/org/jruby/javasupport/ext/JavaLang.java#L221
+    #
+    # This at least allows us to get the message, even though there is no backtrace.
+    def backtrace_locations
+      warn "unsupported backtrace_locations access for #{self.inspect}, dumping normal backtrace; and returning empty"
+      puts self.backtrace
+      return []
+    end
+  end
+end