From 0da823908515ab90de1c188ba01f99873fc8b1aa Mon Sep 17 00:00:00 2001
From: Michael Grosser <michael@grosser.it>
Date: Wed, 1 Apr 2026 18:27:25 -0700
Subject: [PATCH] dump undumpable exceptions without cause if that fixes the
 issue

---
 lib/parallel.rb                               | 11 ++++++++++
 .../parallel_break_with_undumpable_cause.rb   | 20 +++++++++++++++++++
 spec/parallel_spec.rb                         |  5 +++++
 3 files changed, 36 insertions(+)
 create mode 100644 spec/cases/parallel_break_with_undumpable_cause.rb

diff --git a/lib/parallel.rb b/lib/parallel.rb
index d0c3f37..6c79b04 100644
--- a/lib/parallel.rb
+++ b/lib/parallel.rb
@@ -15,6 +15,17 @@ def initialize(value = nil)
       super()
       @value = value
     end
+
+    # marshal_dump that is used for ruby exceptions
+    # avoid dumping the cause since nobody needs that and it can include undumpable exceptions
+    def _dump(_depth)
+      Marshal.dump(@value)
+    end
+
+    # marshal_load that is used for ruby exceptions
+    def self._load(data)
+      new(Marshal.load(data))
+    end
   end
 
   class Kill < Break
diff --git a/spec/cases/parallel_break_with_undumpable_cause.rb b/spec/cases/parallel_break_with_undumpable_cause.rb
new file mode 100644
index 0000000..e91f521
--- /dev/null
+++ b/spec/cases/parallel_break_with_undumpable_cause.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+require './spec/cases/helper'
+
+class UndumpableCauseError < StandardError
+  def initialize
+    super("bad")
+    @binding = binding # can't be dumped when it is the cause
+  end
+end
+
+begin
+  x = Parallel.in_processes(2) do
+    raise UndumpableCauseError
+  rescue StandardError
+    raise Parallel::Break, "hello"
+  end
+  puts "Result: #{x}"
+rescue StandardError => e
+  puts "Error: #{e.class}: #{e.message}"
+end
diff --git a/spec/parallel_spec.rb b/spec/parallel_spec.rb
index 8fe1b0a..445264d 100644
--- a/spec/parallel_spec.rb
+++ b/spec/parallel_spec.rb
@@ -180,6 +180,11 @@ def cpus
       out.should == "NOTHING WAS RAISED"
     end
 
+    it "can handle Break with an undumpable cause" do
+      out = ruby("spec/cases/parallel_break_with_undumpable_cause.rb").strip
+      out.should == "Result: hello"
+    end
+
     it 'can handle to high fork rate' do
       next if RbConfig::CONFIG["target_os"].include?("darwin1") # kills macs for some reason
       ruby("spec/cases/parallel_high_fork_rate.rb").should == 'OK'