troubleshooting: raise on failing pids

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    kubernetes_template_rendering (0.2.1.pre.dc.2)
+    kubernetes_template_rendering (0.2.1.pre.dc.3)
       activesupport
       invoca-utils
       jsonnet

lib/kubernetes_template_rendering/template_directory_renderer.rb

@@ -40,7 +40,7 @@ def render(args)
             else
               # this is the child
               render_set(args, resource_set)
-              Kernel.exit!(3) # skip at_exit handlers since parent will run those
+              Kernel.exit!(0) # skip at_exit handlers since parent will run those
             end
           else
             render_set(args, resource_set)
@@ -72,7 +72,8 @@ def wait_if_max_forked(child_pids)
         rescue SystemCallError # this will happen if they all exited before we called waitpid
         end
         child_pids.delete_if do |pid|
-          Process.waitpid(pid, Process::WNOHANG)
+          [_, exit_status] = Process.waitpid2(pid, Process::WNOHANG)
+          exit_status.success? or raise "Child process #{pid} failed"
         rescue Errno::ECHILD # No child processes
           true
         end

lib/kubernetes_template_rendering/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module KubernetesTemplateRendering
-  VERSION = "0.2.1.pre.dc.2"
+  VERSION = "0.2.1.pre.dc.3"
 end