fix: flatten nested Error objects in details to prevent stack overflow

lib/bolt/error.rb

@@ -10,7 +10,7 @@ def initialize(msg, kind, details = nil, issue_code = nil)
       super(msg)
       @kind = kind
       @issue_code = issue_code
-      @details = details || {}
+      @details = flatten_errors(details || {})
       @error_code ||= 1
     end
 
@@ -38,6 +38,26 @@ def to_puppet_error
       Puppet::DataTypes::Error.from_asserted_hash(to_h)
     end
 
+    private
+
+    # Recursively convert nested Error objects to plain hashes at
+    # construction time, preventing infinite recursion in Puppet's
+    # type inference and JSON serialization (see #3373).
+    def flatten_errors(obj)
+      case obj
+      when Bolt::Error
+        obj.to_h
+      when Hash
+        obj.transform_values { |v| flatten_errors(v) }
+      when Array
+        obj.map { |v| flatten_errors(v) }
+      else
+        obj
+      end
+    end
+
+    public
+
     def self.unknown_task(task)
       command = Bolt::Util.powershell? ? "Get-BoltTask" : "bolt task show"
       new(

spec/unit/error_spec.rb

@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'bolt/error'
+
+describe Bolt::Error do
+  describe '#to_h' do
+    it 'returns a hash with kind, msg, and details' do
+      error = Bolt::Error.new('test message', 'bolt/test-error', { 'key' => 'value' })
+      h = error.to_h
+      expect(h['kind']).to eq('bolt/test-error')
+      expect(h['msg']).to eq('test message')
+      expect(h['details']).to eq({ 'key' => 'value' })
+    end
+
+    it 'includes issue_code when present' do
+      error = Bolt::Error.new('msg', 'bolt/test', {}, 'ISSUE_1')
+      expect(error.to_h['issue_code']).to eq('ISSUE_1')
+    end
+  end
+
+  describe '#to_json' do
+    it 'returns valid JSON' do
+      error = Bolt::Error.new('msg', 'bolt/test', { 'a' => 1 })
+      parsed = JSON.parse(error.to_json)
+      expect(parsed['kind']).to eq('bolt/test')
+      expect(parsed['msg']).to eq('msg')
+    end
+  end
+
+  describe 'nested Error objects in details' do
+    it 'flattens a nested Bolt::Error to a hash' do
+      inner = Bolt::Error.new('inner message', 'bolt/inner-error', { 'inner_key' => 'inner_value' })
+      outer = Bolt::Error.new('outer message', 'bolt/outer-error', { 'error' => inner })
+
+      expect(outer.details['error']).to be_a(Hash)
+      expect(outer.details['error']['kind']).to eq('bolt/inner-error')
+      expect(outer.details['error']['msg']).to eq('inner message')
+      expect(outer.details['error']['details']).to eq({ 'inner_key' => 'inner_value' })
+    end
+
+    it 'flattens deeply nested Bolt::Error objects' do
+      innermost = Bolt::Error.new('deep', 'bolt/deep', {})
+      middle = Bolt::Error.new('mid', 'bolt/mid', { 'cause' => innermost })
+      outer = Bolt::Error.new('top', 'bolt/top', { 'wrapped' => middle })
+
+      expect(outer.details['wrapped']).to be_a(Hash)
+      expect(outer.details['wrapped']['details']['cause']).to be_a(Hash)
+      expect(outer.details['wrapped']['details']['cause']['msg']).to eq('deep')
+    end
+
+    it 'flattens Bolt::Error inside an array in details' do
+      inner = Bolt::Error.new('arr error', 'bolt/arr', {})
+      outer = Bolt::Error.new('top', 'bolt/top', { 'errors' => [inner] })
+
+      expect(outer.details['errors']).to be_an(Array)
+      expect(outer.details['errors'][0]).to be_a(Hash)
+      expect(outer.details['errors'][0]['msg']).to eq('arr error')
+    end
+
+    it 'serializes to JSON without infinite recursion' do
+      inner = Bolt::Error.new('inner', 'bolt/inner', { 'x' => 1 })
+      outer = Bolt::Error.new('outer', 'bolt/outer', { 'error' => inner })
+
+      json = nil
+      expect { json = outer.to_json }.not_to raise_error
+      parsed = JSON.parse(json)
+      expect(parsed['details']['error']['kind']).to eq('bolt/inner')
+    end
+  end
+end